The purpose of the study is to assess the applicability of full factorial experimental design in predicting the ballistic strength of glass fiber/phenolic ballistic composites. In the study we used a number of ballistic composites (20 cm x 20 cm) with different thickness and fiber/resin ratio. The composites were made by an open mold high pressure, high-temperature compression of prepreg layers...

The aim of this work was to present the different current methods of decreasing viscosity of resin composite materials such as (using flowable composites, lowering the viscosity of the monomer mixture, heating composites and applying sonic vibration) and furnish dentists with a basis that can provide criteria for choosing one or another to suit their therapeutic requirements. The four discussed...

Static indentation tests on carbon fibre reinforced laminates have been frequently used in literature to predict the value of penetration energy for the laminate. The mechanical set-up most commonly employed involves the use of indentors of diameter comparable with that of the impactors prescribed from standards for falling weight impact, such as ASTM D3763.The specimen is simply supported usin...

The relationship between wear resistance and filler size or filler loading was clarified for the universal resin composite; however, their relationship in flowable resin composites has not been clarified. The purpose of this study was to investigate the effect of filler size and filler loading on wear of experimental flowable resin composites by using a cyclic loading device. Nine experimental ...

Introdouction: Bleaching has become a common treatment for improving the appearance of natural teeth. However, the need to protect dental restorations from bleaching agent exposure is inevitable, as these agents may change the color of restorative materials by oxidation. Filtek P90 composite resin has recently been introduced with the aim of decreasing polymerization shrinkage. The purpose of...

OBJECTIVES Adhesion of resin composites to dentin is currently believed to result from impregnation of adhesive resin into superficially demineralized dentin. The purpose of this study was to use micro-Raman spectroscopy and scanning electron microscopy (SEM) to investigate the extent of resin penetration into etched dentin with single-step adhesive systems. METHODS Adhesive systems used were...

OBJECTIVE To compare the performance and postoperative sensitivity of a posterior resin composite with that of bonded amalgam in 40 (n = 20) large sized cavities and to evaluate whether resin composite could be an alternative for bonded amalgam. MATERIALS AND METHODS This was a randomized clinical trial. Twenty patients in need of at least two posterior restorations were recruited. Authors ra...

Natural fibers can be attractive reinforcing materials in thermosetting polymers due to their low density and high specific mechanical properties. Although the research effort in this area has grown substantially over the last 20 years, manufacturing technologies to make use of short natural fibers in high volume fraction composites; are still limited. Natural fibers, after retting and preproce...

The indentation test is a popular experimental method to measure a material’s mechanical properties such as elastic modulus and hardness, and the Oliver–Pharr method is commonly used in commercial indentation instruments to obtain these two quantities. To apply the Oliver–Pharr method correctly in all of these cases, it is essential to know the limitations of this method. The present study focu...