OBJECTIVES To evaluate the influence of various photoactivation techniques on the internal gap, Knoop-hardness, and polymerization depth of silorane- and methacrylate-based composites in Class II restorations. METHODS Preparations were made in third molars (n = 10), according to composites (Filtek P60: methacrylate; Filtek P90: silorane) and photoactivation techniques (OC: occlusal photoactiv...

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...

STATEMENT OF THE PROBLEM Polymerization shrinkage stress in composite restorations may lead to microleakage. Clinical methods such as using low-shrinkage composites have been suggested to overcome this problem; however, there are controversies about their efficiency in decreasing the microleakage. PURPOSE This in vitro study was conducted to compare the microleakage of two low-shrinkage resin...

Aim. The aim of this study was to evaluate the effect of different restoration techniques on the formation of internal microgaps between materials and dentin in class V restorations. Materials and Methods. Twenty-five extracted human premolars were prepared with standardized class V cavity outlines (3 mm × 2 mm × 2 mm). The cavities were randomly divided into 5 groups of 10 cavities each and re...

The aim of this study was to determine surface roughness and topography of polished dental resin-based nanocomposites. Four representative dental resin-based nanocomposites were tested in the study: two nanohybrids (Filtek Z550 and Tetric EvoCeram) and two nanofilled (Filtek Ultimate Body and Filtek Ultimate Translucent); and two reference materials: one microfilled (Gradia Direct) and one micr...

Objective: The purpose of this study was to evaluate the effect two hydrogen peroxide concentrations, commonly used in In-Office bleaching, on surface roughness and color change different esthetic restorative materials. Materials Methods: Sixty disc samples (10 mm diameter 2 thickness) materials were constructed following manufacturers’ instructions. Samples classified into three main groups (n...

The mdm2 gene encodes several protein isoforms with different molecular weights (p90, p80, p76 and p57). MDM2 p90 (usually considered to be the major MDM2 protein) binds to and inactivates P53. We have recently shown that growth inhibition of MCF-7 human breast cancer cells by progesterone is associated with P53 down-regulation. In this work, we analyzed the expression pattern of MDM2 proteins ...

Purpose/Objective(s) PET image biomarkers can improve the prediction of radiation-induced late xerostomia in head and neck cancer (HNC) patients [1,2]. A biomarker, 90th percentile (P90) standardized uptake value was identified as a promising predictor for xerostomia, where HNC with lower metabolic activity pre-radiation parotid gland (PG) were more at risk dev...