The aim of this study was to optimize the concentration of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin® TPO) in unfilled and filled composite resins in relation to the degree of conversion (DC). Increasing concentrations of Lucirin® TPO between 0.05-4.97 wt% were added to equimolar mixtures of Bis-GMA/TEGDMA. Filled resins contained 75 wt% fillers. Standardized samples were cured usi...

Acrylic resins have been widely used due to their acceptable esthetics and desirable characteristics such as easy handling, good thermal conductivity, low permeability to oral fluids and color stability. Flexible resins were introduced on the market as an alternative to the use of conventional acrylic resins in the construction of complete and partial removable dentures. Although these resins p...

Poly(vinyl chloride) resins are produced by four basic processes: suspension, emulsion, bulk and solution polymerization. PVC suspensions resins are usually relatively dust-free and granular with varying degrees of particle porosity. PVC emulsion resins are small particle powders containing very little free monomer. Bulk PVC resins are similar to suspension PVC resins, though the particles tend...

STATEMENT OF THE PROBLEM Self-etch adhesives can activate matrix metalloproteinase (MMP) which hydrolyzes organic matrix of demineralized dentin. Epigallocatechin gallate (EGCG), especially found in green tea, could inhibit the activation of MMP. PURPOSE The aim of this study was to evaluate the effect of adding Epigallocatechin gallate (EGCG) into two types of adhesives on dentin bond streng...

the aim of this study was to determine the effects of 40% hydrogen peroxide and 15% carbamide peroxide on microhardness and color change of a silorane-based composite resin in comparison with two methacrylate-based composites.fifty-four disc-shaped specimens (a3 shade) were fabricated of filtek p90 (p90), filtek z350xt enamel (z350) and filtek z250 (z250) (3mespe) (n=18). the samples of each co...

STATEMENT OF PROBLEM Dynamic mechanical properties of hard, direct reline resins are important factors in the clinical success of dentures. However, little information is available on the nature of these properties. PURPOSE This study evaluated the dynamic mechanical properties of a variety of hard, direct reline resins: (1) visible light-polymerized, powder-liquid type, (2) visible light-pol...

A petroleum fluid can be di®ided into three types of species: asphaltenes, resins, and oils. Asphaltenes and resins are polar, while the rest of the so-called oils are either nonpolar or mildly polar. The interaction among these species strongly affect asphaltene precipitation from petroleum fluids. Different measuring methods for asphaltenes in a petroleum fluid gi®e similar results, but diffe...

Abstract Background and Aim: One of the major problems with resin composite restorations is the weakness of bonding between the new and aged composites. Since appropriate micromechanical retention is necessary for the repair of aged resin composite restorations, the level of surface roughness after sandblasting can be influential in this regard. Considering the diverse composition of avail...

Background and Purpose: In people wearing dentures, the growth of various Candida species under the prosthesis leads to the formation of biofilm, which can play the role of a reservoir for Candida and other kinds of microbes. Since nano-chitosan particles can cause lasting antimicrobial activity, a more recent approach that utilizes acrylic resins with nano-chitosan particles is proposed. Th...

to evaluate the ultimate compressive strength of five composite resins after 1 hour, 24 hours, 7 days and 1 month. twenty four cylindrical 4 mm×8mm specimens of each commonly used composite resins in posterior region (nulite-f , z250 , p60, biscore, tetric ceram hb) were prepared. each group of composite resins were divided into four time groups of 1 h, 24 h, 7 days and 1 month. all of specimen...