INTRODUCTION Polymer/clay nanocomposites, in which nanosized silicate plates of clay are uniformly dispersed in the polymer matrix, provide enhanced mechanical and thermal properties compared to conventional composites. Not all polymer and clay combinations will form nanocomposites: the compatibility and interfacial properties between polymer matrix and clay layers significantly influence the e...

We tested some resin-based composites used in dentistry for their estrogenic activity. A sealant based on bisphenol-A diglycidylether methacrylate (bis-GMA) increased cell yields, progesterone receptor expression, and pS2 secretion in human estrogen-target, serum-sensitive MCF7 breast cancer cells. Estrogenicity was due to bisphenol-A and bisphenol-A dimethacrylate, monomers found in the base p...

In general excellent results cannot be guaranteed when using resin-based composites for posterior restorations. This is due to polymerization shrinkage which can still be regarded as the primary negative characteristics of composites.Sevaral factors responsible for the polymerization shrinkage process may negatively affect the integrity of the resoration.The materials shrinkage is associated wi...

STATEMENT OF THE PROBLEM Increasing the thickness of the veneering porcelain may affect the polymerization of resin cements. Incomplete polymerization of resin cements can lead to compromised quality of restoration and decrease the longevity of indirect restorations. PURPOSE This study sought to assess the effect of IPS Empress porcelain thickness on the degree of conversion of light-cure and...

Most of the composites and sealants used in dentistry are based on bisphenol A diglycidylether methacrylate (Bis-GMA) and triethylenglycol dimethacrylate (Teg-DMA). Reports revealed that in situ polymerization is not complete and that free monomers can be detected by different analytical methods. We studied residual Bis-GMA and Teg-DMA after in vitro polymerization by high performance liquid ch...

OBJECTIVES This study examined the influence of the resin thickness on the polymerization of silorane- and methacrylate-based composites. MATERIALS AND METHODS One silorane-based (Filtek P90, 3M ESPE) and two methacrylate-based (Filtek Z250 and Z350, 3M ESPE) composite resins were used. The number of photons were detected using a photodiode detector at the different thicknesses (thickness, 1,...

OBJECTIVES The aim of this study was to develop a low shrinkage visible light curable nanocomposite dental restorative material without sacrificing the other properties of conventional materials. This nanocomposite was developed by using an epoxy resin 3,4-epoxycyclohexylmethyl-(3,4-epoxy)cyclohexane carboxylate (ERL4221) matrix with 55% wt of 70-100 nm nanosilica fillers through ring-opening p...