OBJECTIVES To evaluate the color stability and hardness of two denture liners obtained by direct and indirect techniques, after thermal cycling and immersion in beverages that can cause staining of teeth. MATERIAL AND METHODS Seventy disc-shaped specimens (18 x 3 mm) processed by direct (DT) and indirect techniques (IT) were made from Elite soft (n=35) and Kooliner (n=35) denture liners. For ...

AIM AND OBJECTIVES This in vitro study was designed to comparatively evaluate the effect of five commercial mouth rinses on the micro hardness of a nanofilled resin based restorative material. MATERIALS AND METHODS Fifty specimens of resin composite material (Filtek Z350XT, 3M ESPE, St.Paul, MN USA) were prepared and immersed in artificial saliva for 24 h. The base line micro hardness of spec...

INTRODUCTION Colored compomers are a group of restorative materials that were introduced in 2002 to repair primary teeth, and they provide attractive color and ease of use in pediatric dentistry. The aim of this study was to evaluate the effect of QTH and LED light-curing units on the surface hardness of different colors of Twinky Star compomers. METHODS In this experimental study, a composit...

PURPOSE The aim of the study was to evaluate the effect of annealing on the nanostructure and hardness of Co-Cr metal ceramic samples that were fabricated with a direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS Five groups of Co-Cr dental alloy samples were manufactured in a rectangular form measuring 4 × 2 × 2 mm. Samples fabricated by a conventional casting technique (Gr...

OBJECTIVES This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. MATERIAL AND METHODS A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For th...

This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing ...

functionally graded aluminium/zirconia metal matrix composite was fabricated using stir casting technique followed by horizontal centrifugal casting process and a hollow cylindrical functionally graded composite (150 x 150 x 16 mm) was obtained with centrifuging speed of 1200 rpm. the microstructural evaluation and hardness test was carried out on the outer and inner surface of the functionally...

Laser beam welding produces good quality welds with minimum shrinkage for sheet metal joints. The quality of welded joint depends upon surface morphology, hardness, mixing of liquid phases and metallurgical non-homogeneity induced by gradients of temperatures and cooling rate at the weld interface. In the present investigation, Titanium Grade5 (Ti) and AA2024 (Al) alloy dissimilar sheet metals ...

The present work is aimed at examining carbon steel oil pipelines corrosion using three natural extracts (Eruca Sativa, Rosell and Mango peels) that are used as inhibitors of different concentrations ranging from 0.05-0.1wt. %. Two sulphur compounds are used as corrosion mediums. Weight loss method was used for measuring the corrosion rate of the carbon steel specimens immersed in technical whi...

  Objective: Tooth surface undergoes continuous remineralization and demineralization. The aim of this study was to compare the effect of Caseinphosphopeptide-amorphous calcium phosphate (CPP-ACP) paste and Fluoride gel on the microhardness of demineralized enamel lesions.   Methods: Frothy eight specimens of premolar teeth were chosen and randomly divided to 4 groups of 12. After the initial m...