OBJECTIVES The purpose of the current study was to examine the impact of thermocycling on the development of surface flaws on the cemented surfaces of PLV restorations prepared by acid-etching or alumina (Al2O3) abrasion. METHODS Sets of 30 Vitadur-alpha dentin porcelain discs (15 mm diameter, 0.9 mm thickness) were prepared by either abrading with 50 microm Al2O3 or hydrofluoric (HF) acid-et...

PURPOSE All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS Twenty Lava CAD/...

OBJECTIVES To observe porcelain veneer behavior of zirconia and metal-ceramic full coverage crowns when subjected to compression testing, comparing zirconia cores to metal cores. STUDY DESIGN The porcelain fracture surfaces of 120 full coverage crowns (60 with a metal core and 60 with a zirconia core) subjected to static load (compression) testing were analyzed. Image analysis was performed u...

To elucidate the cause of brittleness of porcelain fused to pure titanium (PFPT) which leads to chipping and cracking similar to that of conventional porcelain in clinical use, fracture toughness KIc, hardness (Hv and Hk) and fracture energy gamma reflecting the bonding energy of atoms were evaluated. In KIc there were no differences between PFPT and conventional porcelain, nor for Hv and Hk, b...

Background and Aim: One of the problems of all ceramic restorations is their risk of fracture due to occlusal loads. The aim of the present study was to compare the effect of two marginal designs (shoulder and chamfer) on the fracture resistance of IPS-emax all ceramic restorations. Materials and Methods: One extracted maxillary first premolar received chamfer 50' marginal preparation (0.8 m...

BACKGROUND The aim of this in vitro study was to compare the mechanical failure behavior and to analyze fracture characteristics of metal ceramic crowns with two veneering systems - press-on metal (PoM) ceramic versus a conventional veneering system - subjected to static compressive loading. MATERIAL AND METHODS Forty-six crowns were constructed and divided into two groups according to porcel...

Mixed salines, 3-methacryloxypropylsilytriisocyanate and 3-mercaptopropyltrimethoxysilane, were used as primers for adhesion of poly(methyl methacrylate) to porcelain teeth, precious alloys and nonprecious alloys. After thermocycle testing, the mean bond strength of the resin to porcelain, silver alloys and stainless steel were excellent. The fracture patterns of porcelain teeth after thermocyc...

STATEMENT OF PROBLEM Bonded porcelain veneers are widely used esthetic restorations. High success and survival rates have been reported, but failures do occur. Fractures are the commonest failure mode. Minimally invasive or thin veneers have gained popularity. Increased enamel and porcelain thickness improve the strength of veneers bonded to enamel, but less is known about dentin or mixed subst...

PURPOSE There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings. MATERIALS AND METHODS Thirty maxillary central incisors were divided into three groups (for each gro...

The purpose of the present study is to examine the relationship between the supportive designs of proximal region of zirconia framework on the fracture load. The zirconia frameworks with four different supportive designs on the proximal region were fabricated and classified with their radiuses of curvature (R): R=0.5 mm, R=1.0 mm, R=1.5 mm, and R=2.0 mm. The zirconia frameworks were conditioned...