MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Dental Materials' source. Tue, 07 Feb 2012 10:08:05 +0100 http://www.medworm.com/index.php?rid=5595308&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009286%2Fabstract%3Frss%3Dyes Abstract: Objectives: To compare the viscoelastic behavior (creep) of dental resin-composites under both static and cyclic loading in compression.Methods: Ten cylindrical specimens (4mm×6mm), divided into two subgroups (n=5) were prepared from each of four commercial resin-composites, using a divisible stainless steel mold. They were thoroughly cured from all sides. Groups 1 and 2 were loaded statically and dynamically respectively after 1d of fabrication and dry storage. Group 1 was loaded with a constant static load of 35MPa and it was applied for 2h followed by 2h of strain recovery to obtain the static creep (%) and permanent set (%) respectively. To Group 2 a cyclic load between 1MPa and 50MPa was applied at a frequency of 0.25Hz for 30min to obtain the “dynamic” creep strain (%)... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595308 Mon, 16 Jan 2012 18:18:02 +0100 5595308 http://www.medworm.com/index.php?rid=5595307&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009055%2Fabstract%3Frss%3Dyes In this study, three bi-layered ceramic models with different geometries are considered: (i) a simple bi-layered plate, (ii) a simple bi-layer triangle, and (iii) an axisymmetric bi-layered crown.Results: The layer thickness and convective heat transfer coefficient (or cooling rate) seem to be more sensitive for the porcelain fused on zirconia substrate models.Significance: The resultant sensitivities indicate a critical importance of the heat transfer coefficient and thickness ratio of core to veneer on the temperature distributions and residual stresses in each model. The findings provide a quantitative basis for assessing the effects of fabrication uncertainties and optimizing the design of ceramic prostheses. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595307 Mon, 16 Jan 2012 18:18:02 +0100 5595307 http://www.medworm.com/index.php?rid=5595306&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008888%2Fabstract%3Frss%3Dyes Abstract: Objectives: Four commercial glass-ionomer cements have been studied for their ability to take up fluoride from aqueous solution following variable maturation times in the dry at 37°C.Methods: Sets of five specimens of four different materials were cured for times of 10min, 24h and 1 month, then transferred to a neutral solution of NaF at approximately 1000ppm in fluoride. Fluoride concentration was then measured at regular time intervals up to 1 month using a fluoride ion selective electrode.Results: Specimens cured for 1 month showed little or no uptake over 24h, specimens cured for 24h showed fluctuating uptake over time, and specimens cured for 10min showed the greatest fluoride uptake. For the latter specimens, simple kinetic models were found to apply in two cases (pseudo-f... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595306 Mon, 16 Jan 2012 18:18:02 +0100 5595306 http://www.medworm.com/index.php?rid=5595305&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008670%2Fabstract%3Frss%3Dyes The objective of this study was to synthesize low viscosity ionic dimethacrylate monomers (IDMAs) that contain quaternary ammoniums groups (antimicrobial functionalities) and are compatible with existing dental dimethacrylate-based monomers. Such monomers have the potential to copolymerize with other methacrylate monomers and produce antibacterial polymers.Methods: Two monomers (IDMA-1 and IDMA-2) were synthesized using the Menschutkin reaction and incorporated at 0–30% (by mass) into a 1:1 (by mass) bisphenol A glycerolate dimethacrylate (BisGMA):triethylene glycol dimethacrylate (TEGDMA) resin. Resin viscosity was quantified using rheology, and polymer degree of conversion (DC) and surface charge density were measured using Fourier transform infrared spectroscopy (FTIR) and fluorescein... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595305 Mon, 16 Jan 2012 18:18:02 +0100 5595305 http://www.medworm.com/index.php?rid=5595304&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008682%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to develop a new method to measure the polymerization shrinkage of light cured composites and to evaluate the overall utility and significance of the technique.Methods: An optical instrument to measure the linear polymerization shrinkage of composites without directly contacting the specimen was developed using a particle tracking method with computer vision. The measurement system consisted of a CCD color video camera, a lens, an image storage device, and image processing and analysis software. The shrinkage kinetics of a commercial silorane-based composite (P90) and two conventional methacrylate-based composites (Z250 and a flowable Z350) were investigated and compared with the data measured using the “bonded disc method”.Results: The l... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595304 Mon, 16 Jan 2012 18:18:02 +0100 5595304 http://www.medworm.com/index.php?rid=5595303&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008694%2Fabstract%3Frss%3Dyes Abstract: Objectives: The purposes of this study were: (1) to determine the light transmission characteristics (straight-line and diffusion transmission) of bulk-filled and layered resin composites, and (2) to evaluate the effect of layering filling on translucency and color appearance of resin composites.Methods: Three light-cured resin composites (EsteliteΣ, Tokuyama Dental; Beautifil II, Shofu and Clearfil Majesty, Kuraray Medical) in A2 and OA2 shades were used in this study. 2mm-thick resin composite discs were prepared by two methods; bulk filling technique (2mm filling at one time), layering technique (two layers each 1mm thickness). The transmitted light intensity of each resin composite disc was measured using a goniophotometer, and diffusion factor (DF), an indicator for diffuse... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595303 Mon, 16 Jan 2012 18:18:02 +0100 5595303 http://www.medworm.com/index.php?rid=5595302&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008700%2Fabstract%3Frss%3Dyes Abstract: Objectives: We investigated the elastic properties of one dental restoration resin composite of common use, Venus Diamond, at submicrometer spatial resolution.Methods: We performed both nanoindentation experiments with atomic force microscopy, and microindentation experiments with a traditional indenter setup. We also used scanning electron microscopy and energy dispersive X-rays spectroscopy to better understand the correlation between properties and microscopic structure and composition.Results: With atomic force microscopy we obtained quantitative evaluation of the elastic modulus (10.8±4.3GPa), in agreement with the microindentation value (reduced modulus of 12.7±2.0GPa), and by microindentation we also obtained an hardness value (460±109MPa) compatible in turn with the no... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595302 Mon, 16 Jan 2012 18:18:02 +0100 5595302 http://www.medworm.com/index.php?rid=5595301&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008724%2Fabstract%3Frss%3Dyes This study characterized the feldspathic ceramic surfaces after various silanization protocols.Methods: Ceramic bars (2mm×4mm×10mm) (N=18) of feldpathic ceramic (VM7, VITA Zahnfabrik) were manufactured and finished. Before silane application, the specimens were ultrasonically cleaned in distilled water for 10min. The ceramic specimens were randomly divided into nine groups (N=2 per group) and were treated with different silane protocols. MPS silane (ESPE-Sil, 3M ESPE) was applied to all specimens and left to react at 20°C for 2min (G20). After drying, the specimens were subjected to heat treatment in an oven at 38°C (G38), 79°C (G79) or 100°C (G100) for 1min. Half of the specimens of each group were rinsed with water at 80°C for 15s (G20B, G38B, G79B, G100B). The control group (GC) ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595301 Mon, 16 Jan 2012 18:18:02 +0100 5595301 http://www.medworm.com/index.php?rid=5595300&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009390%2Fabstract%3Frss%3Dyes This study shows that MNA-loaded electrospun fiber mats represent an interesting class of resorbable drug delivery systems. Sustained drug release properties and cytocompatibility suggest their potential clinical applicability for the treatment of periodontal diseases. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595300 Mon, 16 Jan 2012 18:18:02 +0100 5595300 http://www.medworm.com/index.php?rid=5595299&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009225%2Fabstract%3Frss%3Dyes Abstract: Objective: Dentin hypersensitivity (DH) is a commonly occurring dental condition, and bioactive glasses (BG) are used in dentifrice formulations for treating DH by forming a surface layer of hydroxycarbonate apatite (HCA) on the tooth, thereby occluding exposed dentinal tubules. Fluoride-containing BG, however, form fluorapatite, which is more stable toward acid attack, and provide a more sustainable option for treating DH.Methods: Melt-derived multi-component BG (SiO2–P2O5–CaO–CaF2–SrO–SrF2–ZnO–Na2O–K2O) with increasing CaF2+SrF2 content (0–32.7mol%) were prepared. Apatite formation, occlusion of dentinal tubules in dentin discs and ion release in Tris buffer were characterized in vitro over up to 7 days using X-ray diffraction, infrared spectroscopy, scanning ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595299 Mon, 16 Jan 2012 18:18:02 +0100 5595299 http://www.medworm.com/index.php?rid=5595298&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009018%2Fabstract%3Frss%3Dyes The objective of this study is to investigate the influence of veneer thickness on the stress profile in zirconia- and metal-based structures.Methods: The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The stress profile was measured in bilayered disc samples of 20mm diameter, with a 1mm thick zirconia or metal framework. Different veneering ceramic thicknesses were performed: 1mm, 1.5mm, 2mm, 2.5mm and 3mm.Results: All samples exhibited the same type of stress vs. depth profile, starting with compressive at the ceramic surface, decreasing with depth up to 0.5–1.0mm from the surface, and then becoming compressive again near the framework, except for the 1.5mm-veneered zirconia samples which exhibited interior tensile stresses. S... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595298 Mon, 16 Jan 2012 18:18:02 +0100 5595298 http://www.medworm.com/index.php?rid=5595297&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009006%2Fabstract%3Frss%3Dyes Abstract: Objectives: Dimer acid based metacrylates and TCD-urethane are promoted as new monomers of nano-hybrid resin based composites as alternatives for the conventional BisGMA. Investigations of this study focused on the mechanical and the storage behavior of nano-hybrid resin based composites (RBCs) composed of these new types of monomers in comparison to RBCs using BisGMA.Methods: Flexural strength and modulus were determined in a three-point-bending test. Additionally, the modulus of elasticity was measured on microscopic scale (Emicro) using an automatic microhardness indenter. Tests were performed on samples after 24h storage in distilled water, as well as after thermocycling and storing the materials for four weeks in either distilled water, artificial saliva or ethanol.Results: ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595297 Mon, 16 Jan 2012 18:18:02 +0100 5595297 http://www.medworm.com/index.php?rid=5595296&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008906%2Fabstract%3Frss%3Dyes Abstract: Objectives: Inlay-retained fixed partial dentures are conservative prosthetic restorations. Their failure resistance is influenced by the stress distribution that depends on the material properties as well as the loading conditions. Finite element analysis provides the ability to estimate the loading capacity by simulating the stress distribution in all-ceramic dental restorations. The null-hypothesis of this study was that tooth mobility or tooth bearing condition significantly influences the stress distribution and therefore the failure resistance of all-ceramic inlay-retained fixed dental prostheses. Therefore, the stress distribution under different loading and bearing conditions of the teeth was analyzed using the finite element method.Methods: Three different bearing condit... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595296 Mon, 16 Jan 2012 18:18:02 +0100 5595296 http://www.medworm.com/index.php?rid=5595295&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008967%2Fabstract%3Frss%3Dyes Abstract: Objectives: The study evaluates properties of an experimental dental composite consisting of a porous thermally sintered nano-silica as filler. The properties are compared with those of an experimental composite containing micro fillers and a commercially available nano-composite, Filtek Supreme® Translucent. Different models are used to predict the elastic modulus and strength of the composites.Methods: Nano-silica with primary particles of 12nm was thermally sintered to form nanoporous filer particles. The experimental composites were prepared by incorporating 70wt.% of the fillers into a mixture of Bis-GMA and TEGDMA as matrix phase. Having added photoinitiator system the composites were inserted into the test molds and light-cured. The microfiller containing composites were ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595295 Mon, 16 Jan 2012 18:18:02 +0100 5595295 http://www.medworm.com/index.php?rid=5595294&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008645%2Fabstract%3Frss%3Dyes Abstract: Objectives: The C-Factor has been used widely to rationalize the changes in shrinkage stress occurring at the tooth/resin-composite interfaces. Experimentally, such stresses have been measured in a uniaxial direction between opposed parallel walls. The situation of adjoining cavity walls has been neglected. The aim was to investigate the hypothesis that: within stylized model rectangular cavities of constant volume and wall thickness, the interfacial shrinkage-stress at the adjoining cavity walls increases steadily as the C-Factor increases.Methods: Eight 3D-FEM restored Class I ‘rectangular cavity’ models were created by MSC.PATRAN/MSC.Marc, r2-2005 and subjected to 1% of shrinkage, while maintaining constant both the volume (20mm3) and the wall thickness (2mm), but varying ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595294 Mon, 16 Jan 2012 18:18:02 +0100 5595294 http://www.medworm.com/index.php?rid=5595293&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008384%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the effects of silica (SiO2) (0.5wt%) and zinc oxide (ZnO) (0.25wt%) dopants on the mechanical and biological properties of tricalcium phosphate (TCP) scaffolds with three dimensionally (3D) interconnected pores.Methods: Scaffolds were created with a commercial 3D printer. Post sintering phase analysis was determined by X-ray diffraction. Surface morphology of the scaffolds was examined by field emission scanning electron microscopy (FESEM). Mechanical strength was evaluated with a screw driven universal testing machine. MTT assay was used for cellular proliferation characteristics and cellular morphology was examined by FESEM.Results: Addition of dopants into TCP increased the average density of pure TCP from 90.8±0.8% to 94.1±1.6% and retarded the β t... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595293 Mon, 16 Jan 2012 18:18:02 +0100 5595293 http://www.medworm.com/index.php?rid=5595292&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564112000036%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5595292 Mon, 16 Jan 2012 18:18:02 +0100 5595292 http://www.medworm.com/index.php?rid=5535708&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100858X%2Fabstract%3Frss%3Dyes Abstract: “Nothing worthwhile is ever without complications.”Nora RobertsThe recent increase in reports from clinical studies of ceramic chipping has raised the question of which criteria should constitute success or failure of total-ceramic prostheses. Terminologies such as minor chipping , partial chipping, technical complications , and biological complications have crept into the dental terminology and they have complicated our classification of success and failure of these crown and bridge restorations. Some journals have permitted the reporting of fractures as “complications” and they are not necessarily classified as failures in the study. One study has attempted to classify chipping fractures according to their severity and subsequent treatment . This is a promising approach... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535708 Sat, 24 Dec 2011 03:52:17 +0100 5535708 http://www.medworm.com/index.php?rid=5535707&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008311%2Fabstract%3Frss%3Dyes Abstract: Resin composites have become the first choice for direct posterior restorations and are increasingly popular among clinicians and patients. Meanwhile, a number of clinical reports in the literature have discussed the durability of these restorations over long periods. In this review, we have searched the dental literature looking for clinical trials investigating posterior composite restorations over periods of at least 5 years of follow-up published between 1996 and 2011. The search resulted in 34 selected studies. 90% of the clinical studies indicated that annual failure rates between 1% and 3% can be achieved with Class I and II posterior composite restorations depending on several factors such as tooth type and location, operator, and socioeconomic, demographic, and behaviora... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535707 Sat, 24 Dec 2011 03:52:16 +0100 5535707 http://www.medworm.com/index.php?rid=5535706&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008396%2Fabstract%3Frss%3Dyes This article critically analyzes how the effectiveness of adhesive systems is currently measured, to identify gaps in knowledge where new research could be encouraged. The morphological and chemical analysis of bonded interfaces of resin composite restorations in teeth that had been in clinical service for many years, but were extracted for periodontal reasons, could be a useful tool to observe the ultrastructural characteristics of restorations that are regarded as clinically acceptable. This could help determine how much degradation is acceptable for clinical success. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535706 Sat, 24 Dec 2011 03:52:16 +0100 5535706 http://www.medworm.com/index.php?rid=5535705&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100827X%2Fabstract%3Frss%3Dyes Abstract: Objective: Review correlations of in vivo clinical performance with in vitro laboratory tests of restorative dental materials involving polymer-based matrices. Identify those factors interfering with the process.Materials and methods: An evidence-based dentistry approach was used to identify clinical trials, critical reviews, and meta-analyses involving correlations. Factors impacting meaningful correlations were reviewed. The limited bona fide correlations were reviewed.Results: In vitro tests include physical, chemical, mechanical, and biological properties. Clinical research measurements routinely include 10–15 categories of clinical observations of performance such as color match, caries resistance, marginal integrity, surface texture, and others, but do not correspond well... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535705 Sat, 24 Dec 2011 03:52:16 +0100 5535705 http://www.medworm.com/index.php?rid=5535704&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008281%2Fabstract%3Frss%3Dyes Conclusions: Our community can do a much better job of designing in vitro tests that more closely simulate clinical conditions, especially when contact is involved. Journals are encouraged to thoughtfully consider a ban on publishing papers using bond tests and load-to-failure methods that are seriously flawed and have no clinical relevance. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535704 Sat, 24 Dec 2011 03:52:16 +0100 5535704 http://www.medworm.com/index.php?rid=5535703&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008293%2Fabstract%3Frss%3Dyes Abstract: Objectives: Methods used to measure and predict clinical biological responses to dental materials remain controversial, confusing, and to some extent, unsuccessful. The current paper reviews significant issues surrounding how we assess the biological safety of materials, with a historical summary and critical look at the biocompatibility literature. The review frames these issues from a U.S. perspective to some degree, but emphasizes their global nature and universal importance.Methods: The PubMed database and information from the U.S. Food and Drug Administration, International Standards Organization, and American National Standards Institute were searched for prominent literature addressing the definition of biocompatibility, types of biological tests employed, regulatory and s... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535703 Sat, 24 Dec 2011 03:52:16 +0100 5535703 http://www.medworm.com/index.php?rid=5535702&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008335%2Fabstract%3Frss%3Dyes Abstract: Objectives: This overview is intended to highlight connections between monomer structure and the development of highly crosslinked photopolymer networks including the conversion dependent properties of shrinkage, modulus and stress.Methods: A review is provided that combines the polymer science and dental materials literature along with examples of relevant experimental results, which include measurements of reaction kinetics, photorheology as well as polymerization shrinkage and stress.Results: While new monomers are continually under development for dental materials applications, mixtures of dimethacrylate monomers persist as the most common form of dental resins used on composite restorative materials. Monomer viscosity and reaction potential is derived from molecular structur... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535702 Sat, 24 Dec 2011 03:52:16 +0100 5535702 http://www.medworm.com/index.php?rid=5535701&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008955%2Fabstract%3Frss%3Dyes Abstract: Objectives: Major changes are taking place in dental laboratories as a result of new digital technologies. Our aim is to provide an overview of these changes. In this article the reader will be introduced to the range of layered fabrication technologies and suggestions are made how these might be used in dentistry.Methods: Key publications in English from the past two decades are surveyed.Results: The first digital revolution took place many years ago now with the production of dental restorations such as veneers, inlays, crowns and bridges using dental CAD–CAM systems and new improved systems appear on the market with great rapidity. The reducing cost of processing power will ensure that these developments will continue as exemplified by the recent introduction of a new range ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535701 Sat, 24 Dec 2011 03:52:16 +0100 5535701 http://www.medworm.com/index.php?rid=5535700&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008980%2Fabstract%3Frss%3Dyes The warm and beautiful Costa do Sauipe, in the north of Brazil, set up a great scenario to celebrate the 70th anniversary of the Academy of Dental Materials. The Academy was founded and held its first meeting in 1941. It started as a group of dental professionals who were interested in the development and application of plastic materials to dentistry, and it was called The American Academy for Plastics Research in Dentistry. In 1983, the Academy was reorganized, broadened its scope and, under the leadership of Dr. Evan H. Greener, has become The Academy of Dental Materials (ADM). The Academy journal, Dental Materials, started two years later, in 1985. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535700 Sat, 24 Dec 2011 03:52:16 +0100 5535700 http://www.medworm.com/index.php?rid=5535699&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111009109%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5535699 Sat, 24 Dec 2011 03:52:16 +0100 5535699 http://www.medworm.com/index.php?rid=5378775&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006257%2Fabstract%3Frss%3Dyes Abstract: Objectives: To analyze marginal integrity of resin composites dental restorations using optical coherence tomography (OCT).Methods: Thirty extracted human premolars had occlusal cavities prepared and were randomly divided according to the restorative systems evaluated: Filtek P90™/P90 Adhesive System™, Filtek Z350™, and Filtek Z250™/Single Bond™ (3M/ESPE). The teeth were then stored in the dark for 24h in 0.9% saline solution. Restorations were finished and polished and stored again for 24h before thermocycling (500 cycles, 5–55°C). A commercially available OCT system was used (SR-OCT: OCP930SR/Thorlabs) with 930nm central wavelength. Cross-sectional images were obtained every 250μm and evaluated using Image J. A-scans were analyzed using the Origin 8.0 program, aft... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378775 Sat, 05 Nov 2011 23:51:26 +0100 5378775 http://www.medworm.com/index.php?rid=5378774&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008591%2Fabstract%3Frss%3Dyes Abstract: Objectives: To develop an enhanced, reproducible and discriminatory biocompatibility testing model for non-precious dental casting alloys, prepared to a clinically relevant surface finishing condition, using TR146 oral keratinocyte cells.Methods: Comparative biocompatibility was determined following direct and indirect exposure of TR146 cells to two nickel–chromium (Ni–Cr) and a cobalt–chromium (Co–Cr) alloy-discs. The surface roughness of the discs was determined using a contact stylus profilometer and the elemental ion release by inductively coupled plasma mass spectrometry (ICP-MS). Subsequent biocompatibility analysis included cell morphology, cell density measurements with Trypan blue exclusion assay, inflammatory cytokine expression with ELISAs, cellular metabolic a... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378774 Sat, 05 Nov 2011 23:51:26 +0100 5378774 http://www.medworm.com/index.php?rid=5378773&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008372%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim was to evaluate the stress distribution, comparing an anterior sound tooth with post-endodontic restored teeth under mechanical loading.Methods: A three-dimensional finite element analysis was performed based on micro-CT scan images of a maxillary canine. Twelve models with different crown properties and post-configurations were simulated. The model of the maxillary sound canine was also created and investigated. A load of 50N was applied at a 63° angle with respect to the longitudinal axis of the tooth on the palatal surface of the crown. Principal stresses were registered. Numerical FEA results were statistically analyzed to show the influence of post shape and crown materials.Results: All analyzed models (M1–M12) exhibited a high stress gradient, due to ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378773 Sat, 05 Nov 2011 23:51:26 +0100 5378773 http://www.medworm.com/index.php?rid=5378772&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008323%2Fabstract%3Frss%3Dyes This study implements an experimental method to map the phase transformation, after applying local compressive load until fracture. Such fractures resemble clinically observed chipping failure. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378772 Sat, 05 Nov 2011 23:51:26 +0100 5378772 http://www.medworm.com/index.php?rid=5378771&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008347%2Fabstract%3Frss%3Dyes Abstract: Objectives: CAD/CAM-technologies aim for a standardized, accurate production of dental restorations out of high strength materials (zirconia). The three-dimensional internal fit of CAD/CAM-manufactured zirconia copings was evaluated in vitro to verify the realizability of this aim.Methods: The analysis was based on ceramic master dies of prepared teeth and corresponding virtual CAD surfaces. Five copings per die were manufactured with two different CAD/CAM-technologies: milling and grinding. The internal fit was determined by a three-dimensional replica technique by optical digitization and computer-assisted analysis.Results: Mean internal gaps were 134/84μm (SD 78/28) for molar and 93/69μm (SD 56/35) for premolar copings (milling/grinding) using a digitizable silicone for the ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378771 Sat, 05 Nov 2011 23:51:25 +0100 5378771 http://www.medworm.com/index.php?rid=5378770&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008359%2Fabstract%3Frss%3Dyes This study was therefore intended to clarify the extent to which specimen stiffness affects maximum contact force at different impact velocities. Possible differences between the forces in the eight test chambers were also of interest.Methods: From each of five dental materials differing in Young's modulus, eight cylindrical disks were manufactured and embedded in specimen holders. Alumina spheres were used as antagonists. During chewing simulations with different impact velocities and dental materials, vertical acceleration was recorded and contact forces were estimated on the basis of these measurements.Results: Specimen stiffness and impact velocity had a substantial effect on maximum contact force. The force overshoot relative to the static load ranged from 4% for small specimen stiffn... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378770 Sat, 05 Nov 2011 23:51:25 +0100 5378770 http://www.medworm.com/index.php?rid=5378769&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008360%2Fabstract%3Frss%3Dyes Abstract: Objective: To evaluate the effect of the specimen design on the flexural strength (σf) and failure mode of ceramic structures, testing the hypothesis that the ceramic material under tension controls the mechanical performance of the structure.Methods: Three ceramics used as framework materials for fixed partial dentures (YZ – Vita In-Ceram YZ; IZ – Vita In-Ceram Zirconia; AL – Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs (n=10): monolithic, two layers (porcelain-framework) and three layers (TRI) (porcelain-framework-porcelain). Specimens were tested for three-point flexural strength at 1MPa/s in 37°C artificial saliva. For bi-layered design, the specimens were tested in both condit... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378769 Sat, 05 Nov 2011 23:51:25 +0100 5378769 http://www.medworm.com/index.php?rid=5378768&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100830X%2Fabstract%3Frss%3Dyes Abstract: Objectives: Surface conditions are of interest in all-ceramic restorations since they can control both bonding and strength. Tensile testing methods are commonly used to evaluate surface conditions of ceramics. This work evaluated tensile properties of a feldspathic ceramic as-finished, sandblasted and etched under three stressing conditions: (1) biaxial flexure; (2) monotonic mastication loading, dry; and, (3) cyclic mastication loading, wet.Materials and methods: Feldspathic CAD/CAM blocks were sliced into Tabs 1mm thick, n=135 specimens were divided into 3 groups assigned to as-finished (600 grit SiC; control), sandblasted, and etched. Of the 45 specimens per group, 35 specimens were used for bonded tests and 10 specimens for biaxial flexure testing. Pin-on-three ball biaxial ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378768 Sat, 05 Nov 2011 23:51:25 +0100 5378768 http://www.medworm.com/index.php?rid=5378767&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008189%2Fabstract%3Frss%3Dyes Conclusions: Cantilever bending can be used as an alternative method for bond strength measurement. The ratio of bending to tensile strength is around 1.5. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378767 Sat, 05 Nov 2011 23:51:25 +0100 5378767 http://www.medworm.com/index.php?rid=5378766&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006269%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of the present study was to compare, in situ, the initial dental plaque formation on a recently developed silorane-based composite resin, Filtek Silorane, and on a widely used methacrylate-based composite resin, Synergy D6, and to relate possible differences to surface free energy, hydrophobicity and type of organic matrix.Methods: Discs of Filtek Silorane and Synergy D6 were prepared and polished equally in order to attain the same surface roughness. Water, formamide and 1-bromonaphthalene contact angles were determined and the surface free energy and the hydrophobicity of the materials calculated. Two discs of each material were mounted in individual oral splints and exposed to the oral cavity of 20 participants for 4h. After this period the microbial adhesi... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378766 Sat, 05 Nov 2011 23:51:25 +0100 5378766 http://www.medworm.com/index.php?rid=5378765&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006270%2Fabstract%3Frss%3Dyes Abstract: Objective: To improve its mechanical performance, structural optimization had been used in a previous study to obtain an alternative design for a 3-unit inlay-retained fiber-reinforced composite (FRC) dental bridge. In that study, an optimized layout of the FRC substructure had been proposed to minimize stresses in the veneering composite and interfacial stresses between the composite and substructure. The current work aimed to validate in vitro the improved fracture resistance of the optimized design.Methods: All samples for the 3-unit inlay-retained FRC dental bridge were made with glass-fibers (FibreKor) as the substructure, surrounded by a veneering composite (GC Gradia). Two different FRC substructure designs were prepared: a conventional (n=20) and an optimized design (n=21... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378765 Sat, 05 Nov 2011 23:51:25 +0100 5378765 http://www.medworm.com/index.php?rid=5378764&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008578%2Fabstract%3Frss%3Dyes Abstract: Objectives: The purpose of this study was to characterize the surface morphology and the elastic properties of four dental restorative flowable composites currently on the market (Venus Diamond Flow, Vertise Flow, Filtex Supreme XT Flow, Surefil SDR Flow). Additionally, one adhesive system (Adhese One F) and one non-flowable composite (Venus Diamond) have also been characterized as the control materials.Methods: Surface morphology was studied by both scanning electron and atomic force microscopy, and the elastic modulus and the hardness measured by instrumented indentation. Grain analysis was performed on the microscopic images, and statistical analysis was carried out on the results of the nanoindentation measurements.Results: It was observed that Vertise, Filtek XT and Surefil ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378764 Sat, 05 Nov 2011 23:51:25 +0100 5378764 http://www.medworm.com/index.php?rid=5378763&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002272%2Fabstract%3Frss%3Dyes This study evaluated the effect of different chemical surface treatments on the surface characteristics of commercially pure titanium (cp Ti) and the adhesion of the porcelain–titanium system by means of strain energy release rate (G-value, J/m2). Surface roughness and morphology of treated cp Ti were additionally evaluated.Methods: Two hundred and thirty specimens of machined cp Ti plates grade II were prepared. The specimens were divided into ten groups in each test according to the surface treatment used; Gr 1 (control; machined), Gr 2 (sandblasted), Gr 3 (CH2Cl2 for 5min), Gr 4 (CH2Cl2 for 10min), Gr 5 (10% H2O2 for 5min), Gr 6 (10% H2O2 for 10min), Gr 7 (30% H2O2 for 5min), Gr 8 (30% H2O2 for 10min), Gr 9 (9% HF for 5min) and Gr 10 (9% HF for 10min). Titanium–porcelain (Vita Titan... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378763 Sat, 05 Nov 2011 23:51:24 +0100 5378763 http://www.medworm.com/index.php?rid=5378762&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002314%2Fabstract%3Frss%3Dyes Conclusions: Pressed ceramics compatible with zirconia tested in this study were of two types; leucite containing and non-leucite containing essentially glass ceramics. Leucite containing pressable ceramics appears to have better adhesion to zirconia. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378762 Sat, 05 Nov 2011 23:51:24 +0100 5378762 http://www.medworm.com/index.php?rid=5378761&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100621X%2Fabstract%3Frss%3Dyes This article also provides a list of the variables that should be reported in bond strength studies, regardless of testing methods, to be used by authors conducting future studies, as well as journal reviewers and editors. The goal is to provide guidance and a rationale for what should be included in a study so that reporting might be more standardized and to enhance the possibility that more meaningful comparisons and conclusions may be drawn across studies. The table lists detailed descriptions covering all aspects of testing procedures, including variables related to tooth substrate, restorative material, specimen preparation, pre-testing conditions, testing methods, data reporting and analysis. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378761 Sat, 05 Nov 2011 23:51:24 +0100 5378761 http://www.medworm.com/index.php?rid=5378760&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008748%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5378760 Sat, 05 Nov 2011 23:51:24 +0100 5378760 http://www.medworm.com/index.php?rid=5295058&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001837%2Fabstract%3Frss%3Dyes In this study, we attempted to fabricate a composite material that has mechanical properties similar to biocortical bone and high bioaffinity by compounding hydroxyapatite (HAp) with the base material zirconia (ZrO2), which possesses high mechanical properties and low toxicity toward living organisms.Methods: After mixing the raw material powders at several different ZrO2/HAp mixing ratios, the material was compressed in a metal mold (8mm in diameter) at 5MPa. Subsequently, it was sintered for 5h at 1500°C to obtain the ZrO2/HAp composite. The mechanical property and biocompatibility of materials were investigated. Furthermore, osteoconductivity of materials was investigated by animal studies.Results: A composite material with a minute porous structure was successfully created using ZrO2/... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295058 Sat, 08 Oct 2011 12:43:47 +0100 5295058 http://www.medworm.com/index.php?rid=5295057&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006282%2Fabstract%3Frss%3Dyes The objectives of this study are to investigate the properties of high aspect-ratio hydroxyapatite (HAP) nanofibers and the reinforcing effect of such fibers on bisphenol A glycidyl methacrylate (BisGMA)/triethylene glycol dimethacrylate (TEGDMA) dental resins (without silica microparticle filler) and dental composites (with silica microparticle filler) with various mass fractions (loading rates).Methods: HAP nanofibers were synthesized using a wet-chemical method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and thermal gravimetric analysis (TGA). Biaxial flexural strength (BFS) of the HAP nanofibers reinforced dental resins without any microsized filler and dental composites with silica microparticle filler was tested and analysis of variance (ANOVA) w... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295057 Sat, 08 Oct 2011 12:43:47 +0100 5295057 http://www.medworm.com/index.php?rid=5295056&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006245%2Fabstract%3Frss%3Dyes Abstract: Objectives: The application of an electric field has been shown to positively influence the bonding of dentin bonding systems (DBS) by improving adhesive impregnation into dentin. However, the mechanism responsible for this phenomenon has not been completely elucidated. The aim of this study was to clarify the effects of pH, matrix ionic strength, and applied voltage on the migration of commonly used DBS monomers in a model matrix (agarose gel).Methods: Some common monomers examined were bis-GMA (2,2-bis[4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane); HEMA (2-hydroxyethyl methacrylate); 2-MP (bis[2-(methacryloyloxy) ethyl] phosphate); TCDM [di(hydroxyethyl methacrylate) ester of 5-(2,5,-dioxo tetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic acid]; and TEGDMA... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295056 Sat, 08 Oct 2011 12:43:47 +0100 5295056 http://www.medworm.com/index.php?rid=5295055&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006233%2Fabstract%3Frss%3Dyes Abstract: Objectives: To optimize the compressive fracture strength (σ) and elastic modulus (E) of a glass-ionomer (GI) restorative using poly(acrylic) acid (PAA) weight average molecular weight (Mw) mixtures.Methods: 174 PAA solutions were prepared (four control PAA Mws at three PAA concentrations (25, 35 and 45%) (n=12) and six Mw mixtures (Groups A–F at nine blend ratios and three PAA concentrations (n=162))). The viscosity (η) of each PAA solution was determined using a digital viscometer. The PAA solutions were hand-mixed with a commercial GI restorative powder (Ionofil Molar; Voco, Cuxhaven, Germany) and σ and E were determined using cylindrical (6mm height, 4mm diameter) specimens (n=20) at 24h. Data were analyzed using analyses of variance (ANOVA) (three-, two- and one-way) an... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295055 Sat, 08 Oct 2011 12:43:47 +0100 5295055 http://www.medworm.com/index.php?rid=5295054&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111006221%2Fabstract%3Frss%3Dyes Abstract: Objectives: To investigate the influence of the energy dose on the hardness, polymerization depth, and internal adaptation of silorane and methacrylate-based posterior composites in Class II restorations with different bonding approaches.Materials and methods: Class II preparations were made on the mesial and distal surfaces of extracted third molars and randomly distributed into 6 groups (n=20), according to the restorative systems [methacrylate-based composite: Filtek P60+Adper Single Bond 2 (etch-and-rinse adhesive) – P60/SB; Filtek P60+Adper Easy One (self-etching adhesive) – P60/EO; silorane-based composite: Filtek P90+P90 System Adhesive – P90 (self-etching adhesive)] and the energy dose (20 and 40J/cm2). Resin composites were applied in two increments, individually p... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295054 Sat, 08 Oct 2011 12:43:47 +0100 5295054 http://www.medworm.com/index.php?rid=5295053&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100234X%2Fabstract%3Frss%3Dyes The objectives of the study were to optimize the microstructure of a fine-grained leucite glass-ceramic in order to increase its flexural strength and reliability as measured by its Weibull modulus.Methods: Glass was prepared by a melt-derived method and ground into a powder (M1A). The glass crystallization kinetics were investigated using high temperature XRD and DSC. A series of two-step heat treatments with different nucleation/crystal growth temperatures and holds were carried out to establish the optimized crystallization heat treatment. Glass-ceramics were characterized using XRD, SEM and dilatometry. The glass-ceramic heat treated at the optimized crystallization parameters (M1Aopt) was both sintered (SM1Aopt) and heat extruded (EM1Aopt) into discs and tested using the biaxial flexu... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295053 Sat, 08 Oct 2011 12:43:46 +0100 5295053 http://www.medworm.com/index.php?rid=5295052&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002338%2Fabstract%3Frss%3Dyes Abstract: Objective: The purpose of this work was the study of the effect of the amount of a urethane dimethacrylate silane (UDMS) coupling agent on physical properties of dental light-cured resin nanocomposites based on Bis-GMA/TEGDMA (50/50wt/wt) matrix and Aerosil OX50 as filler.Methods: Silica nanoparticles (Aerosil OX 50) used as filler were silanized with 5 different amounts of UDMS 1.0, 2.5, 5.0, 7.5 and 10wt% relative to silica. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA). Then the silanized nanoparticles (60wt%) were mixed with a Bis-GMA/TEGDMA (50/50wt/wt) matrix. Degree of conversion of light cured composites was determined by FT-IR analysis. The static flexural strength and flexural modulus were measured using ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295052 Sat, 08 Oct 2011 12:43:46 +0100 5295052 http://www.medworm.com/index.php?rid=5295051&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002326%2Fabstract%3Frss%3Dyes This study evaluated the effect of post-polymerization heat-treatments on degree of conversion (DC), residual methyl methacrylate concentration (MMAr) and in vitro cytotoxicity of autopolymerizing acrylic repair resin.Methods: A total of 336 specimens were prepared by bench- and hydroflask-curing and subjected to post-polymerization heat-treatments: a) water immersion at 60°C for 30min, b) microwaving at 500W for 3min, c) combined use of water immersion and microwaving d) no treatment (as control). Specimens were eluted in cell culture medium for 1, 2, 5 and 7 days. DC and MMAr in eluates were measured by FTIR spectrometry and HPLC, respectively. In vitro cytotoxicity of eluates on L-929 fibroblasts was determined by XTT assay. Data were statistically analyzed with Dunn's multiple compari... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295051 Sat, 08 Oct 2011 12:43:46 +0100 5295051 http://www.medworm.com/index.php?rid=5295050&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002302%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the influence of occlusal geometry of all-ceramic pre-molars, namely cusp angle and associated notch radius, on the scatter of load to failure tests.Methods: Forty-five all-ceramic upper pre-molar crowns with three zirconia core thicknesses (0.4, 0.6 and 0.8mm) were broken on dental implant abutments oriented in three angulations (0°, 15°, and 30°). The crowns were loaded using a 4mm diameter steel cylindrical bar placed along the midline fissure at a crosshead speed of 1mmmin−1. The scatter of the failure load was evaluated using Weibull analysis. The cusp angle of each crown was critically evaluated to determine the cusp angle and effective radius of the fissure notch root. The relationship between failure load and cusp angle was compared with that ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295050 Sat, 08 Oct 2011 12:43:46 +0100 5295050 http://www.medworm.com/index.php?rid=5295049&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002296%2Fabstract%3Frss%3Dyes Abstract: Objectives: To measure the marginal and internal fit of three-unit fixed partial dentures (FPDs) using the micro-CT technique, testing the null hypothesis that there is no difference in the adaptation between the ceramic systems studied.Methods: Stainless steel models of prepared abutments were fabricated to design the FPDs. Ten FPDs were produced from each framework ceramic (YZ – Vita In-Ceram YZ and IZ – Vita In-Ceram Zirconia) using CEREC inLab according to the manufacturer instructions. All FPDs were veneered using the recommended porcelain. Each FPD was seated on the original model and scanned using micro-CT. Files were processed using NRecon and CTAn software. Adobe Photoshop and Image J software were used to analyze the cross-sections images. Five measuring locations w... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295049 Sat, 08 Oct 2011 12:43:46 +0100 5295049 http://www.medworm.com/index.php?rid=5295048&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002284%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to evaluate the fracture toughness and surface residual stresses present in various pressable ceramics to zirconia resulting from cooling induced temperature gradients.Materials and methods: Indentation fracture toughness was used to evaluate the residual stress present in various pressable ceramics (Noritake CZR Press, Vita PM9, Wieland PressXzr and IPS e.max ZirPress) to zirconia when subjected to different cooling regimen. The cooling responses of two ceramics were evaluated by thermocouples embedded in the surface of the porcelains and at the porcelain–zirconia interface.Results: The effective Kc results obtained by indentation tests confirmed the presence of surface residual compressive stress for all-ceramic systems subjected to diffe... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295048 Sat, 08 Oct 2011 12:43:45 +0100 5295048 http://www.medworm.com/index.php?rid=5295047&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002260%2Fabstract%3Frss%3Dyes Conclusion: Slow cooling during the final veneering of dental restorations with zirconia frameworks reduces the temperature gradients and residual stresses within the porcelain layer, which represent one possible cause for chipping. An anatomical designed framework did not show the same reduction extent. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295047 Sat, 08 Oct 2011 12:43:45 +0100 5295047 http://www.medworm.com/index.php?rid=5295046&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002090%2Fabstract%3Frss%3Dyes Abstract: Objectives: To provide a brief summary of the background theory of interfacial fracture mechanics and develop an analytical framework that identifies the critical factors for the analysis of the initiation and propagation of adhesion failure in composite restorations.Methods: A conceptual framework utilizing interfacial fracture mechanics and Toya's solution for a partially delaminated circular inclusion in an elastic matrix, which can be applied (with caution) to approximate polymer curing induced cracking about composite resins for class 1 cavity restorations.Results: The findings indicate that: (1) most traditional shear tests are not appropriate for the analysis of the interfacial failure initiation; (2) material properties of the restorative and tooth material have a strong ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295046 Sat, 08 Oct 2011 12:43:45 +0100 5295046 http://www.medworm.com/index.php?rid=5295045&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001850%2Fabstract%3Frss%3Dyes The objective of this study was to investigate the influence of the chemical structure of methacrylate monomers used in dentin adhesives on degree of conversion (DC), water sorption, and dynamic mechanical properties.Materials and methods: Experimental adhesives containing 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane (BisGMA), 2-hydroxyethyl methacrylate (HEMA), and co-monomer, 30/45/25 (w/w) were photo-polymerized. Ethyleneglycol dimethacrylate (EGDM), diethyleneglycol dimethacrylate (DEGDM), triethyleneglycol dimethacrylate (TEGDMA), 1,3-glycerol dimethacrylate (GDM), and glycerol trimethacrylate (GTM) were used as a co-monomer. The adhesives were characterized with regard to DC, water sorption, and dynamic mechanical analysis and compared to control adhesive [HEMA/BisGMA,... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295045 Sat, 08 Oct 2011 12:43:45 +0100 5295045 http://www.medworm.com/index.php?rid=5295044&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001849%2Fabstract%3Frss%3Dyes Abstract: Objectives: The effect of visible light passing through a resin composite with different particle sizes of spherical silica filler on the curing depth and Knoop hardness of the resin composite was examined. The null hypotheses tested were that the particle size of silica filler has no effect on (1) the transmitted amount of visible light passing through the resin composite, (2) the curing depth of the resin composite, and (3) the ratio of the Knoop hardness of the hardened resin composite.Methods: A series of different experimental resin composite pastes with different particle sizes of silica filler were prepared. The amount of visible light passing through each of the experimental resin pastes during the hardening process was determined. The curing depth and Knoop hardness of t... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295044 Sat, 08 Oct 2011 12:43:45 +0100 5295044 http://www.medworm.com/index.php?rid=5295043&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001825%2Fabstract%3Frss%3Dyes Abstract: Objectives: Light-cured composites undergo shrinkage during polymerization. The aim of this study was to evaluate regional shrinkage within a light-cured composite during polymerization by microcomputed tomography and mechanical properties by nanoindentation in bonded or non-bonded class-I cavity.Methods: Zirconium oxide spherical fillers (30μm diameter) were added as markers to a composite resin, filled into a box-shaped class I cavity with or without a bonding agent. The marker fillers were traced in 3D scans obtained by micro-CT before and after polymerization using a software (TRI/3D-BON). The average hardness of the resin composites determined by nanoindentation at each 250μm depth was plotted against depth.Results: In the bonded cavity, the filler particles at the top reg... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295043 Sat, 08 Oct 2011 12:43:45 +0100 5295043 http://www.medworm.com/index.php?rid=5295042&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001813%2Fabstract%3Frss%3Dyes Conclusions: The ion-leachable experimental composites remineralized the human apatite-depleted dentin. Ion release promotes the formation of a bone-like carbonated-apatite on demineralized dentin within 7days of immersion in DPBS.The use of bioactive “smart” composites containing reactive calcium-silicate Portland-derived mineral powder as tailored filler may be an innovative method for the biomimetic remineralization of apatite-depleted dentin surfaces and to prevent the demineralization of hypomineralized/carious dentin, with potentially great advantage in clinical applications. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295042 Sat, 08 Oct 2011 12:43:44 +0100 5295042 http://www.medworm.com/index.php?rid=5295041&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111008487%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5295041 Sat, 08 Oct 2011 12:43:44 +0100 5295041 http://www.medworm.com/index.php?rid=5247926&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001771%2Fabstract%3Frss%3Dyes Abstract: Objective: To assess by means of “thin-slice” push-out test, light and scanning electron microscopy, the interfacial strength and sealing ability of new self-adhesive resin cements when used to lute fiber posts into endodontically treated teeth.Methods: RelyX Unicem 2 Automix (3M ESPE, RUA), Maxcem Elite (Kerr, ME) and seT (SDI, S) were utilized in combination with RelyX Fiber Posts (3M ESPE). In each group 5 posted roots were used for push-out testing and 5 were processed for observations of interfacial morphology and nanoleakage under light microscope and scanning electron microscope. Five to six slices were obtained from each posted root. The statistical significance of the influence on post push-out strength of luting agent, dowel space level, and between-factor interacti... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247926 Sat, 24 Sep 2011 03:38:29 +0100 5247926 http://www.medworm.com/index.php?rid=5247925&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001801%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to test whether the load bearing capacity of anterior zirconia crowns veneered with overpressed or layered, is similar and to evaluate the failure types.Methods: Standardized zirconia frameworks were fabricated and randomly divided into 8 groups (N=120, n=15 per test group). Four groups were veneered with one of the layered veneering porcelains: Zirox, GC Initial ZR, VITA VM9 or IPS e.max Ceram and the other four groups were veneered with overpressed veneering porcelains: PressX Zr, GC Initial LF, VITA PM9 or IPS e.max ZirPress. The crowns were cemented on their corresponding CoCr abutment and the specimens were loaded at an angle of 45° in a Universal Testing Machine to determine the fracture load. Data were analyzed using one-way and two-w... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247925 Sat, 24 Sep 2011 03:38:29 +0100 5247925 http://www.medworm.com/index.php?rid=5247924&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001795%2Fabstract%3Frss%3Dyes Abstract: Objective: To assess the influence of laser-textured surfaces on the adhesion of composite to dentin after being rotary prepared.Methods: Thirty healthy teeth were kept in 0.1% thymol solution prior to being ground down to dentin to create a 4×4mm2 flat surface. Teeth were divided into 3 groups (n=10). Groups 1 and 2 utilized the prototype Erbium doped, Yttrium–Aluminum–Garnet Er:YAG laser by Dental Photonics, Inc. A single pulse was delivered to each spot to create an equally spaced square 4×4mm2 matrix of micro craters. All craters had 100μm diameter/45μm depth; two different spacing patterns were prepared in Groups 1 and 2. In Group 1, distance between crater centers was 50μm; Group 2 had 100μm. In Group 3 (control), 10 samples were prepared without laser texturing. ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247924 Sat, 24 Sep 2011 03:38:29 +0100 5247924 http://www.medworm.com/index.php?rid=5247923&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001783%2Fabstract%3Frss%3Dyes Conclusions: Within the limitations of this study it can be concluded that EQUIA can be used as a permanent restoration material for any sized Class I and in smaller Class II cavities. However, results of ongoing prospective studies shall provide a more exact indication definition in Class II situations.Significance: Modern glass ionomer systems may not only serve as long-term temporaries, but also as permanent restorations in posterior teeth. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247923 Sat, 24 Sep 2011 03:38:28 +0100 5247923 http://www.medworm.com/index.php?rid=5247922&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100176X%2Fabstract%3Frss%3Dyes Abstract: Objective: To evaluate the influence of different surface treatments on the microtensile bond strength of resin cement to zirconia ceramic.Materials and methods: Twelve cylinder-shaped (∅ 12×5.25mm high) blocks of a commercial zirconium-oxide ceramic (Cercon® Zirconia, DENTSPLY) were randomly divided into 4 groups (n=3), based on the surface treatment to be performed: (1) airborne particle abrasion with 125μm Al2O3 particles (S); (2) selective infiltration etching (SIE); (3) experimental hot etching solution applied for 30min (ST) and (4) no treatment (C). Paradigm MZ100 blocks (3M ESPE) were cut into twelve cylinders of 4mm in thickness. Composite cylinders were bonded to conditioned ceramics using a resin cement (Calibra®, DENTSPLY), in combination with the proprietary ad... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247922 Sat, 24 Sep 2011 03:38:28 +0100 5247922 http://www.medworm.com/index.php?rid=5247921&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001758%2Fabstract%3Frss%3Dyes Abstract: Objectives: The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste.Methods: Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic so... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247921 Sat, 24 Sep 2011 03:38:28 +0100 5247921 http://www.medworm.com/index.php?rid=5247920&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001746%2Fabstract%3Frss%3Dyes Abstract: Objective: Test the hypothesis that glass-bonding of free-form veneer and core ceramic layers can produce robust interfaces, chemically durable and esthetic in appearance and, above all, resistant to delamination.Methods: Layers of independently produced porcelains (NobelRondo™ Press porcelain, Nobel BioCare AB and Sagkura Interaction porcelain, Elephant Dental) and matching alumina or zirconia core ceramics (Procera alumina, Nobel BioCare AB, BioZyram yttria stabilized tetragonal zirconia polycrystal, Cyrtina Dental) were joined with designed glasses, tailored to match thermal expansion coefficients of the components and free of toxic elements. Scanning electron microprobe analysis was used to characterize the chemistry of the joined interfaces, specifically to confirm interdi... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247920 Sat, 24 Sep 2011 03:38:28 +0100 5247920 http://www.medworm.com/index.php?rid=5247919&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001734%2Fabstract%3Frss%3Dyes Abstract: Objectives: This work is concerned with the study of the sorption and desorption process of water, ethanol or ethanol/water solution 50% (v/v) or 75% (v/v) by the dental resins prepared by light curing of Bis-GMA, Bis-EMA, UDMA, TEGDMA or D3MA.Methods: A thin resin disc is placed in a bath of time to obtain the sorption curve mt=f(t). Then the liquid is desorbed until a constant mass for the disc is reached and the desorption curve is recorded. These experimental curves help in the determination of the sorbed/desorbed liquid amount at equilibrium, the percentage of the extracted mass of unreacted monomer known as “solubility”, and the sorption/desorption diffusion coefficient which expresses correspondingly the rate of the liquid sorption/desorption.Results: The highest liqui... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247919 Sat, 24 Sep 2011 03:38:28 +0100 5247919 http://www.medworm.com/index.php?rid=5247918&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001722%2Fabstract%3Frss%3Dyes Abstract: Objectives: Polyacid-modified composite resins (compomers) are restorative dental materials that exhibit certain features of traditional dental composites and glass-ionomer cements. The aim of this paper was to develop experimental compomers with enhanced properties, based on adhesive monomers vinyl phosphonic acid and pyromellitic dianhydride glycerol dimethacrylate, and to compare their properties to those of commercially available products.Methods: Factorial experimental design was employed to optimize both chemical and physical properties. Properties such as biaxial flexural strength (BFS), wear resistance (WR), water uptake (WU), and adhesion using shear bond strength (SBS) as well as fluoride release (FR) were evaluated and compared with those of commercial products.Results... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247918 Sat, 24 Sep 2011 03:38:28 +0100 5247918 http://www.medworm.com/index.php?rid=5247917&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001710%2Fabstract%3Frss%3Dyes This study reports real time neutron diffraction on the Empress II glass-ceramic system.Methods. The commercial glass-ceramics was characterized by real time neutron diffraction, 31P and 29Si solid-state MAS-NMR, DSC and XRD.Results. On heating, the as-received glass ceramic contained lithium disilicate (Li2Si2O5), which melted with increasing temperature. This was revealed by neutron diffraction which showed the Bragg peaks for this phase had disappeared by 958°C in agreement with thermal analysis. On cooling lithium metasilicate (Li2SiO3) started to form at around 916°C and a minor phase of cristobalite at around 852°C. The unit cell volume of both Li-silicate phases increased linearly with temperature at a rate of +17×10−3 Å3.°C−1. Room temperature powder X-ray diffraction (XR... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247917 Sat, 24 Sep 2011 03:38:28 +0100 5247917 http://www.medworm.com/index.php?rid=5247916&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001709%2Fabstract%3Frss%3Dyes Abstract: Objective: To use rapid scan FT-IR and Knoop microhardness to determine the effect of specimen temperature on the rate and extent of polymerization of a dental resin.Methods: Two-millimeter thick specimens of shade A2 Tetric EvoCeram were light cured for 20s at 22, 26, 30, and 35°C. The IR spectrum was obtained at the bottom of the specimens at a rate of 3 measurements per second for the first 5min, and then again 2h later. The Knoop microhardness was measured at the bottom of the samples in the region where the IR spectrum was recorded at 5min and 2h after light curing. Data were statistically analyzed using mixed model ANOVA (with Fisher's PLSD) to examine the effect of temperature, time and their interaction. The rate of conversion was determined using first differences and s... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247916 Sat, 24 Sep 2011 03:38:28 +0100 5247916 http://www.medworm.com/index.php?rid=5247915&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001692%2Fabstract%3Frss%3Dyes The objective of this study is to improve the performance of dental resins by adding a small amount of titanium dioxide nanoparticles (TiO2 NPs), which have outstanding mechanical properties and unique photoactivities.Methods: Acrylic acid modified TiO2 NPs (AP25) were prepared and added to a mixture of bis-phenol-A-dimethacrylate and triethylene glycol dimethacrylate (mass ratio 1:1) at seven mass fractions. Disks made of these resins were subjected to FTIR microspectroscopy, nanoindentation, microindentation, and 3-point bending to determine the degree of vinyl conversion (DC) modulus and hardness. The shear bond strengths (SBS) of dentin adhesives containing various amount of AP25 were also examined.Results: The DC increased as a function of mass fraction of AP25 and reached a plateau a... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247915 Sat, 24 Sep 2011 03:38:28 +0100 5247915 http://www.medworm.com/index.php?rid=5247914&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001680%2Fabstract%3Frss%3Dyes Conclusions: The AE technique is an effective tool for detecting and monitoring in situ the interfacial debonding of composite restorations during curing. It can potentially be employed to evaluate the development of shrinkage stress and the quality of interfacial bonds in teeth restored with different composite materials, cavity geometries, and restorative techniques. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247914 Sat, 24 Sep 2011 03:38:28 +0100 5247914 http://www.medworm.com/index.php?rid=5247913&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001679%2Fabstract%3Frss%3Dyes Abstract: Objectives: This retrospective longitudinal study investigated the longevity of posterior restorations placed in a single general practice using 2 different composites in filler characteristics and material properties: P-50 APC (3M ESPE) with 70vol.% inorganic filler loading (midfilled) and Herculite XR (Kerr) with 55vol.% filler loading (minifilled).Methods: Patient records were used for collecting data. Patients with at least 2 posterior composite restorations placed between 1986 and 1990, and still in the practice for regular check-up visits, were selected. 61 patients (20 male, 41 female, age 31.2–65.1) presenting 362 restorations (121 Class I, 241 Class II) placed using a closed sandwich technique were evaluated by 2 operators using the FDI criteria. Data were analyzed wit... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247913 Sat, 24 Sep 2011 03:38:28 +0100 5247913 http://www.medworm.com/index.php?rid=5247912&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002168%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5247912 Sat, 24 Sep 2011 03:38:28 +0100 5247912 http://www.medworm.com/index.php?rid=5107334&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111002119%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107334 Tue, 09 Aug 2011 15:31:36 +0100 5107334 http://www.medworm.com/index.php?rid=5107333&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001461%2Fabstract%3Frss%3Dyes The objective of this work was to develop a methodology for the prediction of fatigue life of the dentin–adhesive (d–a) interface.Methods: At the micro-scale, the d–a interface is composed of dissimilar material components. Under global loading, these components experience different local stress amplitudes. The overall fatigue life of the d–a interface is, therefore, determined by the material component that has the shortest fatigue life under local stresses. Multiple 3d finite element (FE) models were developed to determine the stress distribution within the d–a interface by considering variations in micro-scale geometry, material composition and boundary conditions. The results from these models were analyzed to obtain the local stress concentrations within each d–a interface... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107333 Tue, 09 Aug 2011 15:31:36 +0100 5107333 http://www.medworm.com/index.php?rid=5107332&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100145X%2Fabstract%3Frss%3Dyes Abstract: Objectives: To determine the effect of porcelain thickness and the application of a surface liner (SL) on the flexural strength (σ) of a ceramic system.Methods: One hundred twenty bar-shaped specimens of yttria-stabilized zirconia-based ceramic were fabricated and randomly divided into two groups according to the application of SL: A – applied; B – not applied. The specimens were further divided according to the porcelain veneer thickness (n=20): 0–0.5mm; 1–1.0mm; 2–2.0mm. All specimens were tested in 3-point bending with the porcelain under tension. The maximum load was recorded at first sign of fracture, the σ was calculated and the mode of failure was determined. Data was statistically analyzed using one-way ANOVA, Tukey (α=0.05) and Weibull distribution.Results: ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107332 Tue, 09 Aug 2011 15:31:35 +0100 5107332 http://www.medworm.com/index.php?rid=5107331&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001473%2Fabstract%3Frss%3Dyes Abstract: Objective: To evaluate in vitro the pre-cementation resistance of CAD/CAM onlays subjected to functional occlusal tapping.Methods: An extracted tooth model (molar and premolar) with simulated bone and periodontal ligament was used to make a mesio-occlusal onlay preparation (two mesial cusps covered). Immediate dentin sealing was applied to the prepared tooth. The corresponding onlays were fabricated with Cerec either using composite resin (Paradigm MZ100) or ceramic (e.max CAD and Mark II) (n=14). An elevated marginal ridge was designed with the intention of generating hyper-occlusion. Pre-cementation occlusal tapping was simulated using closed-loop servo-hydraulics at 2Hz, starting with a load of 40N, followed by 80, 120, 160, 200, 240 and 280N (10 cycles each). All samples were... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107331 Tue, 09 Aug 2011 15:31:35 +0100 5107331 http://www.medworm.com/index.php?rid=5107330&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001412%2Fabstract%3Frss%3Dyes Abstract: Objective: This paper studied in vitro the effect of the C-factor on interfacial debonding during curing of composite restorations using the acoustic emission (AE) technique. Finite element (FE) analyzes were also carried out to evaluate the interfacial stresses caused by shrinkage of the composite resin in restorations with different C-factors.Materials and methods: Twenty extracted third molars were divided into 4 groups of 5. They were cut to form Class-I (Groups 1 and 2) and Class-II (Groups 3 and 4) cavities with different C-factors. The average C-factors of the four groups were 3.37, 2.88, 2.00, and 1.79, respectively. The cavities were then applied with an adhesive and restored with a composite, which was cured by a halogen light for 40s. A 2-channel AE system was used to ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107330 Tue, 09 Aug 2011 15:31:34 +0100 5107330 http://www.medworm.com/index.php?rid=5107329&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001370%2Fabstract%3Frss%3Dyes Abstract: Objectives: While screening the activity of potential inhibitors of matrix metalloproteinases (MMPs), due to the limited water solubility of some of the compounds, they had to be solubilized in ethanol. When ethanol solvent controls were run, they were found to partially inhibit MMPs. Thus, the purpose of this study was to compare the MMP-inhibitory activity of a series of alcohols.Methods: The possible inhibitory activity of a series of alcohols was measured against soluble rhMMP-9 and insoluble matrix-bound endogenous MMPs of dentin in completely demineralized dentin. Increasing concentrations (0.17, 0.86, 1.71 and 4.28mol/L) of a homologous series of alcohols (i.e. methanol, ethanol, propanols, butanols, pentanols, hexanols, the ethanol ester of methacrylic acid, heptanols and... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107329 Tue, 09 Aug 2011 15:31:33 +0100 5107329 http://www.medworm.com/index.php?rid=5107327&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001369%2Fabstract%3Frss%3Dyes Conclusion: SS-OCT imaging technology can be used to non-invasively detect and quantify micrometer gaps at the bottom of composite restorations, and potentially become a monitoring tool for composite restorations both in the laboratory research, and in the clinics. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107327 Tue, 09 Aug 2011 15:31:31 +0100 5107327 http://www.medworm.com/index.php?rid=5107326&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001382%2Fabstract%3Frss%3Dyes The objective of this study is to investigate the cooling rate dependence of the stress profile in veneering ceramic layered on metal and zirconia frameworks.Methods: The hole-drilling method, often used for engineering measurements, was adapted for use with veneering ceramic. The stress profile was measured in bilayered disc samples 20mm in diameter, with a 0.7mm thick metal or Yttria-tetragonal-zirconia-polycrystal framework and a 1.5mm thick veneering ceramic. Three different cooling procedures were investigated.Results: The magnitude of the stresses in the surface of the veneering ceramic was found to increase with cooling rate, while the interior stresses decreased. At the surface, compressive stresses were observed in all samples. In the interior, compressive stresses were observed i... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107326 Tue, 09 Aug 2011 15:31:30 +0100 5107326 http://www.medworm.com/index.php?rid=5107325&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001394%2Fabstract%3Frss%3Dyes In this study, we performed analytical and finite element analyses on a cantilever-beam based tensometer that is used to evaluate shrinkage stresses during the polymerization of dental restorative composites.Results: The PS generated by a commercial dental composite determined using our new tensometer agrees with the predicted trend when the beam length and/or specimen height is varied.Significance: This work demonstrates the importance of beam dimension and component relative rigidity to the accuracy of PS evaluation. An analytical solution is also derived for the vertical beam deflection, which can be used for any combination of bending and shearing to properly calculate the PS. In addition, an easy-to-conduct calibration procedure is provided that is desirable for periodic tensometer re... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107325 Tue, 09 Aug 2011 15:31:29 +0100 5107325 http://www.medworm.com/index.php?rid=5107324&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001400%2Fabstract%3Frss%3Dyes Abstract: Objectives: To assess the influence of different temporary restorations and luting techniques of labside and chairside ceramic inlays on enamel defects and marginal integrity.Methods: 120 extracted human third molars received MOD preparations with one proximal box each limited in either enamel or dentin. 64 Cerec 2 inlays and 56 IPS Empress I inlays were randomly assigned to the following groups (fabrication mode: chairside (CS)=no temporary restoration (TR), labside (LS)=TR with Luxatemp (L) inserted with TempBond NE, or Systemp.inlay (SI) without temporary cement), luting technique: SV=Syntac/Variolink II, RX=RelyX Unicem: A: Cerec inlays were luted with (1) CS/SV. (2) CS/SV/Heliobond separately light-cured. (3) CS/RX. (4) LS/L/SV. (5) LS/L/RX. (6) LS/SI/SV. (7) LS/SI/RX. (8) L... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107324 Tue, 09 Aug 2011 15:31:28 +0100 5107324 http://www.medworm.com/index.php?rid=5107322&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001175%2Fabstract%3Frss%3Dyes Abstract: Objective: Investigation of the replacement of bismuth oxide by zirconium oxide in mineral trioxide aggregate (MTA) and characterization and evaluation of the radiopacity and physical properties of varying replacements of zirconium oxide mixed at either water–powder or water–cement proportions of 0.3. The suitable filler loading of zirconium oxide for Portland cement in a MTA system for use as a root-end filling material was thus determined.Methods: Portland cement replaced by zirconium oxide in varying amounts ranging from 0% to 50% in increments of 10 was mixed with water either at a water/powder (WP) proportion or at a water/cement (WC) proportion of 0.3. Portland cement and ProRoot MTA were used as controls. The materials’ microstructures were investigated using optical... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107322 Tue, 09 Aug 2011 15:31:27 +0100 5107322 http://www.medworm.com/index.php?rid=5107321&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001187%2Fabstract%3Frss%3Dyes Conclusions: MTA interacts with other dental materials with resultant elemental migration in adjacent materials. Zinc oxide eugenol based cements should be avoided in the presence of MTA as zinc causes retardation of cement hydration with increased porosity. Glass ionomer cements absorb the water of hydration from the MTA also resulting in increased porosity and incomplete hydration of MTA. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107321 Tue, 09 Aug 2011 15:31:25 +0100 5107321 http://www.medworm.com/index.php?rid=5107320&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001357%2Fabstract%3Frss%3Dyes Abstract: Objectives: Microleakage testing of dental materials is a commonly accepted evaluation technique of margin integrity. Thermocycling has been utilized by many researchers to study the influence of temperature extremes on the marginal gap of cemented restorations. The aim of this investigation was to analyze microleakage data on cemented crowns, published in the dental literature until Dec 2009, to identify methodological factors that might potentially affect the results of in vitro microleakage tests and to compare the results.Methods: The following databases were included: Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations and Ovid MEDLINE(R) 1950 to Present, Ovid-MEDLINE(R) 1950 to Present with Daily Update, EMBASE, EBM Reviews – Cochrane Database of Systematic Reviews a... Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107320 Tue, 09 Aug 2011 15:31:24 +0100 5107320 http://www.medworm.com/index.php?rid=5107319&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001990%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=5107319 Tue, 09 Aug 2011 15:31:24 +0100 5107319 http://www.medworm.com/index.php?rid=4975667&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100162X%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975667 Tue, 28 Jun 2011 22:59:49 +0100 4975667 http://www.medworm.com/index.php?rid=4975666&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001199%2Fabstract%3Frss%3Dyes Abstract: Objectives: The purpose of this study was to evaluate polymerization shrinkage of resin composites using a coordinate measuring machine, optical coherence tomography and a more widely known method, such as Archimedes Principle. Two null hypothesis were tested: (1) there are no differences between the materials tested; (2) there are no differences between the methods used for polymerization shrinkage measurements.Methods: Polymerization shrinkage of seven resin-based dental composites (Filtek Z250™, Filtek Z350™, Filtek P90™/3M ESPE, Esthet-X™, TPH Spectrum™/Dentsply 4 Seasons™, Tetric Ceram™/Ivoclar-Vivadent) was measured. For coordinate measuring machine measurements, composites were applied to a cylindrical Teflon mold (7mm×2mm), polymerized and removed from the ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975666 Tue, 28 Jun 2011 22:59:48 +0100 4975666 http://www.medworm.com/index.php?rid=4975665&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100114X%2Fabstract%3Frss%3Dyes Abstract: Objectives: Finite element analysis is a standard method to simulate the stress distribution in all-ceramic dental restorations in order to estimate the loading capacity of the brittle components. The hypothesis of this study was that stresses in the connector area of a veneered FDP are strongly influenced by the framework dimensions and the veneering material.Methods: Finite element analyzes of bilayered fixed dental prostheses with three different framework-designs and three different veneering materials were conducted, applying the loads onto the veneering as well as directly onto the framework. The outer shape of the veneering ceramic remained constant for all cases.Results: The maximum first principal stresses in the framework of the fixed dental prostheses (FDP) decreased w... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975665 Tue, 28 Jun 2011 22:59:48 +0100 4975665 http://www.medworm.com/index.php?rid=4975664&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001163%2Fabstract%3Frss%3Dyes This study aimed at investigating the microstructure, pH and leaching in physiological solution of Portland cement replaced zirconium oxide at either water–powder or water–cement ratios of 0.3 for use as a root-end filling material. The hydration characteristics of the materials which exhibited optimal behavior were evaluated.Methods: Portland cement replaced by zirconium oxide in varying amounts ranging from 0 to 50% in increments of 10 was prepared and divided into two sets. One set was prepared at a constant water/cement ratio while the other set at a constant water/powder ratio of 0.3. Portland cement and MTA were used as controls. The materials were analyzed under the scanning electron microscope (SEM) and the hydration products were determined. X-ray energy dispersive analysis (E... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975664 Tue, 28 Jun 2011 22:59:47 +0100 4975664 http://www.medworm.com/index.php?rid=4975663&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001151%2Fabstract%3Frss%3Dyes Abstract: Objectives: Investigation and characterization of the replacement of the Portland cement component in mineral trioxide aggregate (MTA) with tricalcium silicate cement which is manufactured using the sol-gel method from pure raw materials.Methods: Tricalcium silicate and Portland cement were characterized by viewing under the scanning electron microscope (SEM) and surface imaging and elemental analysis with X-ray energy dispersive analysis (EDX), and by X-ray diffraction analysis with Rietveld refinement. In addition the hydration products of the material after 28 days of curing were evaluated by plotting atomic ratio plots from the EDX data. The cement leachate was evaluated for pH and chemical composition by inductively coupled plasma.Results: Portland cement was composed of 68%... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975663 Tue, 28 Jun 2011 22:59:47 +0100 4975663 http://www.medworm.com/index.php?rid=4975662&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001138%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this work was the synthesis of light-cured resin nanocomposites using nanosilica particles with different particle size and the study of some physical–mechanical properties of the composites.Methods: Various types of silica nanoparticles (Aerosil) with average particle size of 40, 20, 16, 14, and 7nm, used as filler were silanized with the silane 3-methacryloxypropyl-trimethoxysilane (MPS). The total amount of silane used was kept constant at 10wt% relative to the filler weight to ensure the complete silanization of nanoparticles. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA). Then the silanized nanoparticles (55wt%) were mixed with a photoactivated Bis-GMA/TEGDMA (50/50wt/wt) matrix. Degre... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975662 Tue, 28 Jun 2011 22:59:47 +0100 4975662 http://www.medworm.com/index.php?rid=4975661&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001126%2Fabstract%3Frss%3Dyes Abstract: A great challenge regarding the ease-of-use of composites involves the development of ‘self-adhesive’ composites that no longer require a separate adhesive to bond to tooth enamel/dentin.Objectives: To characterize the interfacial ultra-structure of an experimental self-adhesive filling material bonded to enamel and dentin using transmission electron microscopy (TEM).Methods: The experimental self-adhesive material was bonded to bur-cut human enamel and dentin, and to fractured (smear-free) dentin, strictly according to the manufacturers’ instructions. The specimens were stored for 1 day in distilled water (37°C) prior to further common specimen processing for TEM.Results: The experimental self-adhesive filling material revealed a typical micro-hybrid filler distribution. ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975661 Tue, 28 Jun 2011 22:59:47 +0100 4975661 http://www.medworm.com/index.php?rid=4975660&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001114%2Fabstract%3Frss%3Dyes Abstract: Objectives: This paper presents a novel array-chip technology used to monitor the physical properties of dental composites in situ. The DECAY chip (Degradation via Electrochemical Array) leverages microfabrication techniques to construct a uniform array of recessed wells that may be filled with dental restorative materials (e.g. composite or amalgam) and analyzed electrochemically in solution.Methods: The array enables the uniform preparation of multiple specimens and reference controls on a common substrate, all of which may be simultaneously evaluated. The DECAY-chip presented here consists of a 3×3 array of 100μm deep wells, and is used to monitor the degradation of a common dental composite as a function of time.Results: The data correlate changes in the measured dielectric... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975660 Tue, 28 Jun 2011 22:59:46 +0100 4975660 http://www.medworm.com/index.php?rid=4975659&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001102%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the stickiness of unset resin-composites, at different speeds and temperatures, in terms of maximum probe separation-force (Fmax) and work-of-separation (Ws).Materials and methods: Eight commercial light-cured resin-composites were selected. Each material was placed in a cylindrical mold (φ=7mm×5mm depth) held at 25°C or 37°C. The maximum force (Fmax, N) and work probe separation (Ws, Nmm) were measured by using a texture analyzer to register force/displacement. A flat-ended stainless-steel probe (φ=6mm) was mechanically lowered onto and into the surface of the unset sample. When a ‘trigger’ compressive force of 0.05N was registered, data-acquisition commenced. Descent continued until a compressive force of 1N was reached, which was held constant ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975659 Tue, 28 Jun 2011 22:59:46 +0100 4975659 http://www.medworm.com/index.php?rid=4975658&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100090X%2Fabstract%3Frss%3Dyes Conclusion: The results of the wear test with steatite or enamel antagonists indicated no measurable wear on zirconia surfaces. Porcelain showed higher wear than zirconia, but comparable or lower wear than an enamel reference. Antagonistic wear against zirconia was found to be lower than wear against porcelain. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975658 Tue, 28 Jun 2011 22:59:46 +0100 4975658 http://www.medworm.com/index.php?rid=4975657&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000893%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to evaluate the effect of fatigue on biaxial flexural strength of bilayered disks of two Y-TZP cores.Methods: Twenty bilayered veneer/zirconia disks were fabricated from each material (Lava veneer+core, 3M/ESPE, and Cercon veneer+core, Densply). Ten specimens from each material were tested for biaxial flexural strength either with or without being subjected to fatigue (20,000 cycles, 2Hz, 200N load) in a universal testing machine (1mm/min). Stresses generated at the core and the veneer, at the top and the bottom surfaces, and the interface of bilayered disk were calculated using Huesh's solutions. Data were statistically analyzed using Weibull statistics. The fractured core was also examined via Raman spectroscopy and the monoclinic fraction ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975657 Tue, 28 Jun 2011 22:59:45 +0100 4975657 http://www.medworm.com/index.php?rid=4975656&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000881%2Fabstract%3Frss%3Dyes Abstract: Objective: To compare long-term microtensile bond strength of zirconia, surface-modified via a novel treatment, to current surface conditioning methods for zirconia, when resin bonded to dental composite.Methods: Two ProCAD (porcelain) and 10 sintered ZirCAD (ZrO2) blocks (18mm×14mm×12mm) were obtained from manufacturers. Twelve Herculite XRV composite blocks were fabricated (18mm×14mm×12mm). Bonding surface of blocks was polished through 1200-grit SiC and air-abraded (50μm alumina, 0.28MPa, 20s). Blocks were then separated into six groups: (1) porcelain (control), HF-etched/silane-treated, (2) ZrO2, tribochemical-coated/silane-treated, (3) ZrO2, primer-treated, (4) ZrO2, modified via novel 3.2nm silica layer/silane-treated, (5) ZrO2, modified via novel 5.8nm silica layer/si... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975656 Tue, 28 Jun 2011 22:59:45 +0100 4975656 http://www.medworm.com/index.php?rid=4975655&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100087X%2Fabstract%3Frss%3Dyes Conclusion: Streptococcal adhesion forces to orthodontic composite resins increase with increasing roughness of the composite surfaces. Composite surface roughness less affects adhesion forces with S. mutans than with S. sanguinis. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975655 Tue, 28 Jun 2011 22:59:45 +0100 4975655 http://www.medworm.com/index.php?rid=4975654&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000868%2Fabstract%3Frss%3Dyes The objectives of this study were to synthesize novel nanoparticles of amorphous calcium phosphate (NACP), develop NACP nanocomposite with calcium (Ca) and phosphate (PO4) ion release to combat caries, and investigate the effects of NACP filler level and glass co-filler reinforcement on composite properties.Methods: NACP (diameter=116nm) were synthesized via a spray-drying technique for the first time. Since the local plaque pH in the oral cavity can decrease to 5 or 4, photo-activated composites were tested with immersion in solutions of pH 7, 5.5, and 4. Composite mechanical properties as well as Ca and PO4 ion release were measured vs. pH and filler level.Results: Increasing the NACP filler level increased the ion release. At 28 d and pH 4, the Ca release was (4.66±0.05)mmol/L at 20% N... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975654 Tue, 28 Jun 2011 22:59:45 +0100 4975654 http://www.medworm.com/index.php?rid=4975653&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000856%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to investigate the mechanical properties of denture base resin cross-linked with methacrylated dendrimer.Methods: The test specimens (3mm×10mm×65mm) were fabricated from autopolymerizing resin with the powder/liquid ratio of 10g/7ml. The monomer liquid of resin was applied with the mixture of methylmethacrylate and crosslinker dendrimer (DD1) or crosslinker ethyleneglycol dimethacrylate (EGDMA) with five different volume percentages (vol%). The dendrimer crosslinker in this study is a methacrylated molecule (MW=3617g/mol) with 12 methacrylate groups. Quantity of crosslinkers varied from 1.1 to 9.1vol%. The specimens (n=8/group) were polymerized in distilled water maintained at 55°C under pressure of 0.4MPa for 20min. Test specimens were st... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975653 Tue, 28 Jun 2011 22:59:44 +0100 4975653 http://www.medworm.com/index.php?rid=4975652&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000844%2Fabstract%3Frss%3Dyes In this study acetyloxypropylene dimethacrylate was synthesized and proposed as an alternative monomer for triethyleneglycol dimethacrylate (TEGDMA) in dental mixtures.Methods: The monomer was prepared by the reaction of glycerol dimethacrylate with acetic anhydride. The exchange reaction was carried out in the presence of catalytic amounts of sulfuric acid. After purification the monomer was mixed with 2,2-dimethoxy-2-phenyloacetophenone and photo-irradiated. Unfilled homopolymer was evaluated for photopolymerization conversion and volumetric curing shrinkage. Water sorption, water solubility, flexural strength and hardness were measured. Also, dynamic mechanical studies were performed. For comparison TEGDMA was homopolymerized and its properties were evaluated.Results: The proposed dimet... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975652 Tue, 28 Jun 2011 22:59:44 +0100 4975652 http://www.medworm.com/index.php?rid=4975651&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100131X%2Fabstract%3Frss%3Dyes The objective of this meta-analytical study was to review the literature on the short- and long-term release of components from resin-based dental materials, and to determine how much (order of magnitude) of those components may leach out in the oral cavity.Methods: Out of an initial set of 71 studies, 22 were included. In spite of the large statistical incertitude due to the great variety in methodology and lack of complete information (detection limits were seldom mentioned), a meta-analytical mean for the evaluated eluates was calculated. To relate the amount of potentially released material components with the size of restorations, the mean size of standard composite restorations was estimated using a 3D graphical program.Results: While the release of monomers was analyzed in many stud... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975651 Tue, 28 Jun 2011 22:59:44 +0100 4975651 http://www.medworm.com/index.php?rid=4975650&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001497%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4975650 Tue, 28 Jun 2011 22:59:44 +0100 4975650 http://www.medworm.com/index.php?rid=4883401&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001308%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883401 Wed, 01 Jun 2011 03:23:13 +0100 4883401 http://www.medworm.com/index.php?rid=4883400&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000911%2Fabstract%3Frss%3Dyes This study evaluated the human pulp response to the application of two RMGICs in deep cavities in vivo. Methods: The cavity floor prepared on the buccal surface of 34 premolars was lined with VBP (VBP), Vitrebond (VB) or Dycal® (DY), and restored with composite resin. Additional teeth were used as an intact control group. After 7 or 30–60 days, the teeth were extracted and processed for histological evaluation. The following histological events were scored: inflammatory response, tissue disorganization, reactionary dentin formation and presence of bacteria. Results: At 7 days, VBP and VB elicited a mild inflammatory pulpal response in about 70% of specimens and in 1 specimen for DY. Only 1 specimen of each RMGICs exhibited moderate tissue disorganization. Bacteria and reactionary dentin... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883400 Wed, 01 Jun 2011 03:23:12 +0100 4883400 http://www.medworm.com/index.php?rid=4883399&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000819%2Fabstract%3Frss%3Dyes Abstract: Aim: An innovative light-curable calcium-silicate cement containing a HEMA–TEGDMA-based resin (lc-MTA) was designed to obtain a bioactive fast setting root-end filling and root repair material.Methods: lc-MTA was tested for setting time, solubility, water absorption, calcium release, alkalinizing activity (pH of soaking water), bioactivity (apatite-forming ability) and cell growth-proliferation. The apatite-forming ability was investigated by micro-Raman, ATR-FTIR and ESEM/EDX after immersion at 37°C for 1–28 days in DPBS or DMEM+FBS. The marginal adaptation of cement in root-end cavities of extracted teeth was assessed by ESEM/EDX, and the viability of Saos-2 cell on cements was evaluated.Results: lc-MTA demonstrated a rapid setting time (2min), low solubility, high calcium... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883399 Wed, 01 Jun 2011 03:23:11 +0100 4883399 http://www.medworm.com/index.php?rid=4883398&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000765%2Fabstract%3Frss%3Dyes Abstract: Objective: The aim of this paper is to validate the use of a finite-element (FE) based continuum damage mechanics (CDM) failure model to simulate the debonding and fracture of restored teeth.Materials and methods: Fracture testing of plastic model teeth, with or without a standard Class-II MOD (mesial–occusal–distal) restoration, was carried out to investigate their fracture behavior. In parallel, 2D FE models of the teeth are constructed and analyzed using the commercial FE software ABAQUS. A CDM failure model, implemented into ABAQUS via the user element subroutine (UEL), is used to simulate the debonding and/or final fracture of the model teeth under a compressive load. The material parameters needed for the CDM model to simulate fracture are obtained through separate mech... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883398 Wed, 01 Jun 2011 03:23:09 +0100 4883398 http://www.medworm.com/index.php?rid=4883397&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000923%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the effect of the microstructure on the Weibull and slow crack growth (SCG) parameters and on the lifetime of three ceramics used as framework materials for fixed partial dentures (FPDs) (YZ – Vita In-Ceram YZ; IZ – Vita In-Ceram Zirconia; AL – Vita In-Ceram AL) and of two veneering porcelains (VM7 and VM9).Methods: Bar-shaped specimens were fabricated according to the manufacturer's instructions. Specimens were tested in three-point flexure in 37°C artificial saliva. Weibull analysis (n=30) and a constant stress-rate test (n=10) were used to determine the Weibull modulus (m) and SCG coefficient (n), respectively. Microstructural and fractographic analyzes were performed using SEM. ANOVA and Tukey's test (α=0.05) were used to statistically analyze ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883397 Wed, 01 Jun 2011 03:23:08 +0100 4883397 http://www.medworm.com/index.php?rid=4883396&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000832%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to investigate the effectiveness of a variety of techniques to bond new composite to artificially aged composite of different compositions.Methods: Composite resin blocks were made of five different commercially available composites (n=30) (Clearfil AP-X, Clearfil PhotoPosterior, Photo Clearfil Bright, Filtek Supreme XT and HelioMolar). After aging the composite blocks (thermo-cycling 5000×), blocks were subjected to one of 9 repair procedures: no treatment (control), diamond bur, sandblasting alumina particles, CoJet™, phosphoric acid, 3% hydrofluoric acid 20s or 120s, 9.6% hydrofluoric acid 20s or 120s. In addition, the cohesive strength of the tested composites was measured. Two-phase sandwiches (‘repaired composite’) were prepared ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883396 Wed, 01 Jun 2011 03:23:08 +0100 4883396 http://www.medworm.com/index.php?rid=4883395&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000820%2Fabstract%3Frss%3Dyes Abstract: Objectives: To compare the clinical wear performance of nanofilled restorations (Filtek Supreme) against microhybrid restorations (Z100) in a 5-year randomized clinical trial to evaluate the wear rate and the influence of subject-, operator- and restoration-related variables on wear rate.Materials and methods: 18 Filtek Supreme and 17 Z100 restorations were placed in human molars (split-mouth-model) and bonded with Single Bond/Scotch Bond Adhesive. Restorations were recalled at baseline, 6-, 12-months and at annual intervals until 5-years of clinical service. The gypsum replicas at each recall were used for 3D-Pro-laser scanning to quantify wear and the epoxy resin replicas were observed under SEM for microwear patterns. Linear-mixed-models were used to study the influence of the... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883395 Wed, 01 Jun 2011 03:23:08 +0100 4883395 http://www.medworm.com/index.php?rid=4883394&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000807%2Fabstract%3Frss%3Dyes Conclusions: Although the “hipped” Y-TZP showed favorable initial mechanical properties, no significant difference could be found in the susceptibility of both ceramics to subcritical crack growth and their long-term strength. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883394 Wed, 01 Jun 2011 03:23:07 +0100 4883394 http://www.medworm.com/index.php?rid=4883393&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000790%2Fabstract%3Frss%3Dyes Abstract: Objectives: SUS 304 stainless steels have been widely used in orthodontics and implants such as archwires, brackets, and screws. The purpose of present study was to investigate the biocompatibility of both the commercial microcrystalline biomedical 304 stainless steel (microcrystalline 304ss) and novel-fabricated nanocrystalline 304 stainless steel (nanocrystalline 304ss).Methods: Bulk nanocrystalline 304ss sheets had been successfully prepared by microcrystalline 304ss plates using severe rolling technique. The electrochemical corrosion and ion release behavior immersion in artificial saliva were measured to evaluate the property of biocorrosion in oral environment. The cell lines of murine and human cell lines from oral and endothelial environment were co-cultured with extracts... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883393 Wed, 01 Jun 2011 03:23:06 +0100 4883393 http://www.medworm.com/index.php?rid=4883392&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000789%2Fabstract%3Frss%3Dyes Abstract: Objectives: In a previous study, a 60% increase in push-out strength was obtained in vitro with a two-step cementation of fiber posts, a procedure equivalent to the layering technique of composite restorations. The aim of this study is to find the rationale for this increase in push-out strength with finite element analysis (FEA).Methods: FEA models were created of the push-out test set-up of fiber posts cemented according to a one-step and two-step procedure and of the complete root with post. The failure loads of glass-fiber posts cemented with RelyX Unicem as obtained in a previous study were used as the load in the push-out FEA models. For the complete root model, a load of 100N was used. The stresses due to the shrinkage of the cement layer and the applied load were determin... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883392 Wed, 01 Jun 2011 03:23:06 +0100 4883392 http://www.medworm.com/index.php?rid=4883391&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000777%2Fabstract%3Frss%3Dyes Abstract: Objectives: To assess the elastic modulus (EM), volumetric shrinkage (VS), and polymerization shrinkage stress (PSS) of experimental highly filled nanohybrid composites as a function of matrix composition, filler distribution, and density.Methods: One regular viscosity nanohybrid composite (Grandio, VOCO, Germany) and one flowable nanohybrid composite (Grandio Flow, VOCO) were tested as references along with six highly filled experimental nanohybrid composites (four Bis-GMA-based, one UDMA-based, and one Ormocer®-based). The experimental composites varied in filler size and density. EM values were obtained from the “three-point bending” load–displacement curve. VS was calculated with Archimedes’ buoyancy principle. PSS was determined in 1-mm thick specimens placed betwee... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883391 Wed, 01 Jun 2011 03:23:05 +0100 4883391 http://www.medworm.com/index.php?rid=4883390&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000753%2Fabstract%3Frss%3Dyes Abstract: Objectives: The purpose of this study was to evaluate the effect of preparation order on the crystal structure of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and the shear bond strength of dental resin cements.Methods: One-hundred fifty pre-sintered Y-TZP cylinders (Ø 9mm×13.5mm) were prepared and divided into three groups (control group, SBS group and SAS group). Specimens in control group were not treated. Specimens in SBS group were sandblasted and then densely sintered, and specimens in SAS group were sintered in advance, and then sandblasted. The specimens were analyzed by X-ray diffractometry, confocal laser scanning microscopy and Energy dispersive X-ray spectroscopy before and after sandblasting. All specimens were embedded in polytetrafluoroethylene (PTFE... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883390 Wed, 01 Jun 2011 03:23:04 +0100 4883390 http://www.medworm.com/index.php?rid=4883389&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000741%2Fabstract%3Frss%3Dyes Abstract: Objectives: To assess the effects of surface finishing condition (polished or alumina particle air abraded) on the biocompatibility of direct and indirect exposure to a nickel–chromium (Ni–Cr) d.Sign®10 dental casting alloy on oral keratinocytes. Biocompatibility was performed by assessing cellular viability and morphology, metabolic activity, cellular toxicity and presence of inflammatory cytokine markers.Methods: Discs of d.Sign®10 were cast, alumina particle air abraded and half were polished before surface roughness was determined by profilometry. Biocompatibility was assessed by placing the discs directly or indirectly (with immersion solutions) into contact with TR146 monolayers. Metal ion release was determined by ICP-MS. Cell viability was assessed by trypan blue dy... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883389 Wed, 01 Jun 2011 03:23:03 +0100 4883389 http://www.medworm.com/index.php?rid=4883388&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100073X%2Fabstract%3Frss%3Dyes Abstract: Objectives: Silver containing materials have been used for years as antimicrobial materials. Silver particles were also added to experimental dental composites to reduce caries. The aim of our study was to show whether silver nanoparticles can lead to higher amounts of elutable substances.Methods: 0.0125, 0.025, 0.05, 0.1 and 0.3% by weight silver nanoparticles were added to the commercial composite Tetric Flow®. After light curing of the specimen, they were stored up to 7 days in methanol. The eluate was analyzed by gas chromatography/mass spectrometry.Results: Compared to controls more camphorquinone (CQ), ethoxylated bisphenol-A-dimethacrylate (BisEMA) and triethylene glycol dimethacrylate (TEGDMA) will be eluted when silver nanoparticles were added to the composite. Twenty-f... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883388 Wed, 01 Jun 2011 03:23:03 +0100 4883388 http://www.medworm.com/index.php?rid=4883387&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000546%2Fabstract%3Frss%3Dyes Abstract: Objective: A novel resin composite system, Filtek Silorane (3M ESPE) with reduced polymerization shrinkage has recently been introduced. The resin contains an oxygen-containing ring molecule (‘oxirane’) and cures via a cationic ring-opening reaction rather than a linear chain reaction associated with conventional methacrylates and results in a volumetric shrinkage of ∼1%. The purpose of this study was to review the literature on a recently introduced resin composite material, Filtek Silorane, and evaluate the clinical outcome of restorations formed in this material.Methods: Filtek Silorane restorations were placed where indicated in loadbearing situations in the posterior teeth of patients attending five UK dental practices. These were evaluated, after two years, using modi... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883387 Wed, 01 Jun 2011 03:23:02 +0100 4883387 http://www.medworm.com/index.php?rid=4883386&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000935%2Fabstract%3Frss%3Dyes Abstract: The history, scope, structural components, generation, and purpose of international dental standards are concisely surveyed by three researchers active in standards development.Significance: Standards have an important role to play within dental materials research alongside more specialist scientific instruments and methods. For all that are concerned with the wider business and safety issues of manufacture, marketing, selection and use of dental biomaterials and devices, knowledge of the vital role of standards is indispensable. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883386 Wed, 01 Jun 2011 03:23:02 +0100 4883386 http://www.medworm.com/index.php?rid=4883385&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001217%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4883385 Wed, 01 Jun 2011 03:23:02 +0100 4883385 http://www.medworm.com/index.php?rid=4775288&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111001047%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775288 Tue, 03 May 2011 08:25:58 +0100 4775288 http://www.medworm.com/index.php?rid=4775287&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000534%2Fabstract%3Frss%3Dyes Abstract: Objectives: Piston-on-three-ball tests have been selected by the International Organization for Standardization to establish ISO 6872 for the evaluation of the biaxial strength of dentistry–ceramic materials. However, the formula adopted in ISO 6872 for the fracture load-biaxial strength relationship was an approximate equation originally derived for piston-on-ring tests of monolayered discs. This formula was modified and extended to the case of multilayered discs subjected to piston-on-ring loadings recently. The purpose of the present study is to evaluate the adequacy of applying the formula for piston-on-ring to piston-on-three-ball tests for both monolayered and multilayered discs.Methods: Finite element analyses were performed to simulate both piston-on-three-ball and pist... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775287 Tue, 03 May 2011 08:25:58 +0100 4775287 http://www.medworm.com/index.php?rid=4775286&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100039X%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to evaluate the load-bearing capacity and microstrain of incisors restored with posts of various kinds. Both prefabricated titanium posts and different fiber-reinforced composite posts were tested.Methods: The crowns of human incisors were cut and post preparation was carried out. The roots were divided into groups: (1) prefabricated serrated titanium posts, (2) prefabricated carbon fiber-reinforced composite posts, (3) individually formed glass fiber-reinforced composite posts with the canal full of fibers, and (4) individually formed “split” glass fiber-reinforced composite posts. The posts were cemented and composite crowns were made. Intact human incisors were used as reference. All roots were embedded in acrylic resin cylinders and s... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775286 Tue, 03 May 2011 08:25:58 +0100 4775286 http://www.medworm.com/index.php?rid=4775285&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000698%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim of this study was to investigate the effects of HEMA and TEGDMA on the odontogenic differentiation potential of dental pulp stem/progenitor cells.Methods: Dental stem/progenitor cell cultures were established from pulp biopsies of human deciduous teeth of 1–3 year-old children (Deciduous Teeth Stem Cells-DTSCs). Cultures were characterized for stem cell markers, including STRO-1, CD146, CD34, CD45 using flow cytometry. Cytotoxicity was evaluated with the MTT assay. DTSCs were then induced for osteo/odontogenic differentiation by media containing dexamethasone, KH2PO4,β-glycerophosphate and l-ascorbic acid phosphate in the presence of nontoxic concentrations of HEMA (0.05–0.5mM) and TEGDMA (0.05–0.25mM) for 3weeks. Additionally, the effects of a single e... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775285 Tue, 03 May 2011 08:25:57 +0100 4775285 http://www.medworm.com/index.php?rid=4775284&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000686%2Fabstract%3Frss%3Dyes Abstract: Objectives: The purpose of this work was the detailed study of sorption characteristics of water or artificial saliva, the determination of flexural strength and the flexural modulus, and the study of the thermal stability of some current commercial dental light-cured nanocomposites containing nano-sized filler particles.Methods: Three nanohydrid dental composites (Tetric EvoCeram (TEC), Grandio (GR) and Protofill-nano (PR)) and two nanofill composites (Filtek Supreme Body (FSB) and the Filtek Supreme Translucent (FST)) were used in this work. The volumetric shrinkage due to polymerization was first determined. Also the sorption, solubility and volumetric increase were measured after storage of composites in water or artificial saliva for 30 days. The flexural strength and flexur... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775284 Tue, 03 May 2011 08:25:57 +0100 4775284 http://www.medworm.com/index.php?rid=4775283&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000674%2Fabstract%3Frss%3Dyes Abstract: Objectives: To compare the bond strength of a ceramic veneer material to two different ceramic core materials using shear strength testing and finite element analysis (FEA).Methods: 15 blocks of ceramic cores were made of each of IPS e.max ZirCAD (Ivoclar-Vivadent, Schaan, Liechtenstein) (ZirCAD) and lithium disilicate IPS e.max CAD (LS). These were veneered using IPS e.max Ceram (Ceram) according to the manufacturers’ instructions. Samples were then mounted, placed inside a shear testing jig and loaded at their core/veneer interfaces with a universal testing machine. Fractured specimens were then examined fractographically at 45×. An independent t-test and a Mann–Whitney U test were used to detect differences in bond strengths and the patterns of failure between the two gro... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775283 Tue, 03 May 2011 08:25:57 +0100 4775283 http://www.medworm.com/index.php?rid=4775282&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100056X%2Fabstract%3Frss%3Dyes Abstract: Titanium implants are the gold standard in dentistry; however, problems such as gingival tarnishing and peri-implantitis have been reported. For zirconia to become a competitive alternative dental implant material, surface modification techniques that induce guided tissue growth must be developed.Objectives: To develop alternative surface modification techniques to promote guided tissue regeneration on zirconia materials, for applications in dental implantology.Methods: A methodology that combined soft lithography and sol–gel chemistry was used to obtain isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates. The materials were characterized via chemical, structural, surface morphology approaches. In vitro biological behavior was evaluated in terms of... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775282 Tue, 03 May 2011 08:25:56 +0100 4775282 http://www.medworm.com/index.php?rid=4775281&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000558%2Fabstract%3Frss%3Dyes Abstract: Objectives: Less data are available about the effects of hydrogen peroxide on the three-dimensional polymer network of polymerized composites. Therefore the study was performed to test the effects of hydrogen peroxide on the three-dimensional polymer network in composites.Methods: Polymerized specimens from Tetric Flow®, Tetric Ceram® and Filtek™ Supreme XT were bleached with Opalescence® PF 15% for 5h or PF 35% for 0.5h, respectively, and then stored in methanol for 1d and 7d. Controls were unbleached specimens. The eluates were analyzed by gas chromatography/mass spectrometry.Results: More methacrylic acid (MAA), bisphenol-A (BPA), ethoxylated bisphenol-A-dimethacrylate (BisEMA), hydroquinone monomethyl ether (HQME), 1,10-decanediol dimethacrylate (DDDMA) and/or triethylen... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775281 Tue, 03 May 2011 08:25:56 +0100 4775281 http://www.medworm.com/index.php?rid=4775280&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000418%2Fabstract%3Frss%3Dyes Abstract: Objective: To compare microtensile bond strengths (MTBS) subsequent to load cycling of resin bonded acid-etched or EDTA-treated dentin using a modified ethanol wet-bonding technique.Methods: Flat dentin surfaces were obtained from extracted human molars and conditioned using 37% H3PO4 (PA) (15s) or 0.1M EDTA (60s). Five experimental adhesives and one commercial bonding agent were applied to the dentin and light-cured. Solvated experimental resins (50% ethanol/50% comonomers) were used as primers and their respective neat resins were used as the adhesives. The resin-bonded teeth were stored in distilled water (24h) or submitted to 5000 loading cycles of 90N. The bonded teeth were then sectioned in beams for MTBS. Modes of failure were examined by scanning electron microscopy.Resul... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775280 Tue, 03 May 2011 08:25:55 +0100 4775280 http://www.medworm.com/index.php?rid=4775279&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000297%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the micro-tensile bond strength (μTBS) and interfacial characteristics of adhesive–dentin bonds produced after caries-removal with contemporary techniques.Methods: Carious molars were cut at the base of the fissure, exposing ‘sound’ and ‘carious’ dentin at different spots. After caries-excavation, a composite was bonded using a 2-step self-etch adhesive. The μTBS was measured and the mode of fracture analyzed using a stereomicroscope and imaged by Feg-SEM, while additional non-fractured specimens were histologically analyzed after Masson's trichrome staining in order to identify potentially incompletely resin-enveloped collagen.Results: μTBS to residual caries-excavated dentin was lower than to sound dentin. The different caries-removing techn... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775279 Tue, 03 May 2011 08:25:54 +0100 4775279 http://www.medworm.com/index.php?rid=4775278&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS010956411100025X%2Fabstract%3Frss%3Dyes Abstract: Objective: To investigate the influence of curing mode and temperature on the shrinkage kinetics of self-adhesive resin cements in comparison to a conventional multi-step resin cement.Methods: The shrinkage of self-adhesive resin cements Maxcem Elite (MX), Speedcem (SPC), Smartcem2 (SMC), iCem (IC) and RelyX Unicem (RX) and Nexus Third Generation (NX3) as a multi-step resin cement was measured continuously for 1h using the bonded disk method. All materials were tested with dual-curing (dc) and self-curing (sc) mode. All measurements (n=5 per group) were conducted at room temperature (23°C) as well as at body temperature (37°C). Shrinkage time constants were obtained from a simple exponential growth model. Data were statistically analyzed by ANOVA and the p-values were adjusted ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775278 Tue, 03 May 2011 08:25:54 +0100 4775278 http://www.medworm.com/index.php?rid=4775277&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000248%2Fabstract%3Frss%3Dyes Abstract: Objectives: The aim was to investigate the influence of number average molecular weight and concentration of the poly(acrylic) acid (PAA) liquid constituent of a GI restorative on the compressive fracture strength (σ) and modulus (E).Methods: Series of PAA solutions for eight experimental PAAs with molecular weights ranging from 5000 to 200,000 were prepared at concentrations ranging from 10 to 60%. The PAA number average molecular weights were determined using gel permeation chromatography and the viscosity at each concentration was determined using a digital viscometer. The PAA solutions were hand-mixed with a commercial GI restorative powder (Ionofil Molar; Voco, Cuxhaven, Germany). σ and E were determined at 24h using cylindrical (6mm height, 4mm diameter) specimens (n=20).... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775277 Tue, 03 May 2011 08:25:53 +0100 4775277 http://www.medworm.com/index.php?rid=4775276&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000236%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the mechanical behavior of a prototype porous ceramic interpenetrating polymer–ceramic material containing 15–20% polymer.Methods: After sample preparation, elastic modulus, hardness, stress–strain relationship and indentation creep response were measured by a nanoindentation system. Fracture toughness was measured by the single-edge-notched beam (SENB) method. SEM was employed to observe the fractured surface and analyze the fracture mechanisms.Results: The polymer infiltrated ceramic material has elastic modulus, hardness, and fracture toughness values of 30.14GPa, 2.59GPa, and 1.72 MPam1/2, respectively. The material illustrates a significant indentation size effect for elastic modulus and hardness, and has similar indentation creep behavior to hu... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775276 Tue, 03 May 2011 08:25:53 +0100 4775276 http://www.medworm.com/index.php?rid=4775275&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000212%2Fabstract%3Frss%3Dyes Abstract: Objective: To investigate the contributions of BisGMA:TEGDMA and filler content on polymerization stress, along with the influence of variables associated with stress development, namely, degree of conversion, reaction rate, shrinkage, elastic modulus and loss tangent for a series of experimental dental composites.Methods: Twenty formulations with BisGMA:TEGDMA ratios of 3:7, 4:6, 5:5, 6:4 and 7:3 and barium glass filler levels of 40, 50, 60 or 70wt% were studied. Polymerization stress was determined in a tensilometer, inserting the composite between acrylic rods fixed to clamps of a universal test machine and dividing the maximum load recorded by the rods cross-sectional area. Conversion and reaction rate were determined by infra-red spectroscopy. Shrinkage was measured by mercu... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775275 Tue, 03 May 2011 08:25:53 +0100 4775275 http://www.medworm.com/index.php?rid=4775274&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000200%2Fabstract%3Frss%3Dyes This study demonstrates the effects of nano-scale prepolymer particles as additives to model dental monomer and composite formulations.Methods: Discrete nanogel particles were prepared by solution photopolymerization of isobornyl methacrylate and urethane dimethacrylate in the presence of a chain transfer agent, which also provided a means to attach reactive groups to the prepolymer. Nanogel was added to triethylene glycol dimethacrylate (TEGDMA) in increments between 5 and 40wt% with resin viscosity, reaction kinetics, shrinkage, mechanical properties, stress and optical properties evaluated. Maximum loading of barium glass filler was determined as a function of nanogel content and composites with varied nanogel content but uniform filler loading were compared in terms of consistency, con... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775274 Tue, 03 May 2011 08:25:52 +0100 4775274 http://www.medworm.com/index.php?rid=4775273&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000996%2Fabstract%3Frss%3Dyes (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4775273 Tue, 03 May 2011 08:25:52 +0100 4775273 http://www.medworm.com/index.php?rid=4658214&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564110005130%2Fabstract%3Frss%3Dyes The second authors’ name was incorrectly listed as V.X. Tran in this article. The authors’ name is now correctly listed as Xuan-Vinh Tran above. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658214 Thu, 31 Mar 2011 07:27:20 +0100 4658214 http://www.medworm.com/index.php?rid=4658213&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000194%2Fabstract%3Frss%3Dyes This report presents a novel pretreatment technique, whereby the zirconia surface is converted to a more reactive zirconium oxyfluoride, enabling improved chemical bonding to other dental substrates via conventional silanation approaches.Methods: The study leverages a novel gas-phase fluorination process that creates a thin oxyfluoride conversion layer on the surface of zirconia, making it more reactive for conventional adhesive bonding techniques. Zirconia specimens, polished and roughened, were pretreated and composite cylinders bonded using conventional adhesive techniques. All specimens were subjected to a force at a crosshead speed of 0.5mm/min in an electro-mechanical testing device. Single-factor analysis of variance (ANOVA) at a 5% confidence level was performed for the bonding str... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658213 Thu, 31 Mar 2011 07:27:20 +0100 4658213 http://www.medworm.com/index.php?rid=4658212&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000157%2Fabstract%3Frss%3Dyes Abstract: Objectives: Methacrylic monomers are released, from dental composite resins, either into the oral cavity or in pulpal tissues, where they can cause local or systemic adverse effects. The mechanisms of these effects are not well understood, probably because such molecules can act at different levels also inducing a depletion of intracellular glutathione (GSH). GSH can detoxify methacrylates by conjugating their α,β-unsaturated carbon–carbon moiety to the thiol group, with the catalysis of glutathione S-transferases (GST). This reaction determines a GSH cellular depletion and belongs to the metabolism of α,β-unsaturated esters, protecting the body against the toxic effects of electrophiles. On the basis of the above considerations, this work aim is to set up a method for the ... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658212 Thu, 31 Mar 2011 07:27:19 +0100 4658212 http://www.medworm.com/index.php?rid=4658211&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000145%2Fabstract%3Frss%3Dyes Abstract: The aim of this study was to assess the cytotoxicity of orthodontic materials (brackets, wires, resin, elastomers and silver solder) using Saccharomyces cerevisiae as a model organism. The induction of cytotoxicity was assessed by two different tests using the wild-type S. cerevisiae strain FF18733: (1) direct exposure to orthodontic materials in YPD broth, and (2) exposure to artificial commercial saliva pre-treated with orthodontic materials. Only the silver solder was tested in mutant S. cerevisiae strains to investigate the origin of the observed cytotoxicity. Colony forming units per mL counts were carried out in all experiments and compared to controls to detect significant survival differences. The results showed that only the silver solder induced significant cytotoxicity... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658211 Thu, 31 Mar 2011 07:27:18 +0100 4658211 http://www.medworm.com/index.php?rid=4658210&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000285%2Fabstract%3Frss%3Dyes Abstract: Objectives: To evaluate the influence of different tertiary amines on degree of conversion (DC), shrinkage-strain, shrinkage-strain rate, Knoop microhardness, and color and transmittance stabilities of experimental resins containing BisGMA/TEGDMA (3:1wt), 0.25wt% camphorquinone, 1wt% amine (DMAEMA, CEMA, DMPT, DEPT or DABE). Different light-curing protocols were also evaluated.Methods: DC was evaluated with FTIR-ATR and shrinkage-strain with the bonded-disk method. Shrinkage-strain-rate data were obtained from numerical differentiation of shrinkage-strain data with respect to time. Color stability and transmittance were evaluated after different periods of artificial aging, according to ISO 7491:2000. Results were evaluated with ANOVA, Tukey, and Dunnett's T3 tests (α=0.05).Resu... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658210 Thu, 31 Mar 2011 07:27:18 +0100 4658210 http://www.medworm.com/index.php?rid=4658209&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000273%2Fabstract%3Frss%3Dyes Conclusions: This study developed a novel antibacterial glass-ionomer cement. Within the limitations of this study, it appears that the experimental cement is a clinically attractive dental restorative due to its high mechanical strength and antibacterial function. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658209 Thu, 31 Mar 2011 07:27:17 +0100 4658209 http://www.medworm.com/index.php?rid=4658208&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000261%2Fabstract%3Frss%3Dyes Conclusions: This study developed a novel resin-modified glass-ionomer cement system composed of newly synthesized hyperbranched poly(acrylic acid)s. It appears that this novel experimental cement is a clinically attractive dental restorative and may potentially be used for high-wear and high-stress-bearing site restorations. (Source: Dental Materials) Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658208 Thu, 31 Mar 2011 07:27:17 +0100 4658208 http://www.medworm.com/index.php?rid=4658207&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000224%2Fabstract%3Frss%3Dyes This study examined the use of sodium trimetaphosphate (STMP) as a biomimetic analog of matrix phosphoproteins for remineralization of artificial carious-affected dentin.Methods: Artificial carious lesions with lesion depths of 300±30μm were created by pH-cycling. 2.5% hydrolyzed STMP was applied to the artificial carious lesions to phosphorylate the partially-demineralized collagen matrix. Half of the STMP-treated specimens were bonded with One-Step. The adhesive and non-adhesive infiltrated specimens were remineralized in a Portland cement-simulated body fluid system containing polyacrylic acid (PAA) to stabilize amorphous calcium phosphate as nanoprecursors. Micro-computed tomography (micro-CT) and transmission electron microscopy (TEM) were used to evaluate the results of remineraliz... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658207 Thu, 31 Mar 2011 07:27:16 +0100 4658207 http://www.medworm.com/index.php?rid=4658206&cid=s_35508_173_f&fid=35508&url=http%3A%2F%2Fwww.demajournal.com%2Farticle%2FPIIS0109564111000170%2Fabstract%3Frss%3Dyes Abstract: Objectives: In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended Class II cavities was observed over six years.Methods: Thirty patients received 68 direct resin composite restorations (Solobond M+Grandio: n=36; Syntac+Tetric Ceram: n=32) by one dentist in a private practice. All restorations were replacement fillings, 35% of cavities revealed no enamel at the bottom of the proximal box, in 48% of cavities remaining proximal enamel width was 0.05; Mann–Whitney U-test). Molar restorations performed worse regarding marginal integrity (4 years), filling integrity (6, 12, 24, 48 months), and tooth integrity (4 and 6 years). Irrespective of the resin composite used, significant changes over time were found for all criteria rec... Dental Materials journals http://www.medworm.com/rss/comments.php?id=4658206 Thu, 31 Mar 2011 07:27:15 +0100 4658206