statement of problem: the degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency. objectives: in the present study, we evaluated the effects of different light- curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversi...

Composite restorations are popular because of their superior esthetics and acceptable clinical performance. But shrinkage is still a drawback. Polymerization shrinkage results in volumetric contraction, leading to deformation of the cusps, microleakage, decrease of marginal adaptation, enamel micro-cracks and postoperative sensitivity. A new class of ring opening resin composite based on silora...

We investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP+10% SA for 10 minutes (HP+SA), 16% CP alone, or...

Introduction: This in vitro study aimed to evaluate the effect of different monomer systems on microleakage in class II composite open sandwich restorations with and without a separating agent placed between the nanofilled resin modified glass ionomer and the resin. Materials and methods: Class II cavity preparations were prepared in maxillary premolars (n = 240) and the cervical limit of the p...

STATEMENT OF THE PROBLEM The adhesion of resin-modified glass-ionomer (RMGI) to composite resin has a very important role in the durability of sandwich restorations. Hydroxyapatite is an excellent candidate as a filler material for improving the mechanical properties of glass ionomer cement. PURPOSE The aim of this study was to assess the effect of adding micro- and nano-hydroxyapatite (HA) p...

objectives: dental composite wear in posterior restorations is a concern and is affected by different factors. this study was conducted to evaluate the effect of polishing and mechanical loads on wear of silorane-based and methyl methacrylate-based composites resins. materials and methods: of each dental composite (filtek p90 and filtek p60), 40 samples were fabricated in a polyethylene mold (4...

STATEMENT OF THE PROBLEM Composite bond to dentin is crucial in many clinical conditions particularly in deep cavities without enamel margins due to insufficient penetration of adhesive into demineralized dentin. PURPOSE The aim of this study was to assess the shear bond strength (SBS) of a methacrylate-based and a silorane-based composite resin to surface and deep dentin after pretreatment w...

STATEMENT OF PROBLEM The bond strength between restorative material and tooth structure is so important for conduction of durable restoration. Considering the recent attention to low shrinkage composite resins, evaluation of micro tensile bond strength of these materials would be valuable. OBJECTIVES To compare the microtensile bond strength of silorane composite resin (Filtek P90) with the c...

We compared polymerization stress in two commercial composites and three experimental composites made using camphorquinone (CQ) and/or phenylpropanedione (PPD) as photoinitiators. The internal surfaces of photoelastic resin discs with cylindrical cavities were roughened and treated with adhesive. Composites were divided into five groups: two commercial composites (Filtek Silorane and Filtek Z25...