PURPOSE This in vitro study compared the effect of five different techniques on the surface roughness of feldspathic porcelain. MATERIALS AND METHODS 100 feldspathic porcelain disk samples mounted in acrylic resin blocks were divided into five groups (n=20) according to type of surface treatment: I, hydrofluoric acid (HFA); II, Deglazed surface porcelain treated with Neodymium:yttrium- alumin...

The widespread use of porcelain in restorative dentistry is generally due to its esthetic appearance even though it is brittle. The transverse strength, or modulus rupture, averages around 108 MPa (16,000 psi) for aluminous porcelain and 88 MPa (13,000 psi) for feldspathic porcelain. The tensile strength, as determined by diametral compression, is approximately 29 MPa (4,200 psi) for opaque fel...

PURPOSE Porcelain chipping has been one of the main problems of porcelain-fused-to-zirconia restorations. This study evaluates the bond strengths of layered, pressed, and adhesively bonded porcelain to yttria-stabilized zirconia substrates that have undergone traditional preparation or gas-phase fluorination. MATERIALS AND METHODS A three-point bending test was used to evaluate the bond stren...

This study evaluated the masking ability of different porcelain thicknesses and combination of enamel and/or dentin porcelain layers over simulated background dental substrates with higher (A2) and lower (C4) color values. Combination of the enamel (E) and dentin (D) monolayer porcelain disks with different thicknesses (0.5 mm, 0.8 mm, and 1 mm) resulted in the following bilayer groups (n=10): ...

The shear bond strength of composite resin to porcelain was investigated to optimize variables for bonding porcelain laminate veneers. Scanning electron microscopy was initially used to examine the surface configuration of porcelain prepared under various conditions. A factorial experiment was undertaken to determine the effects of three different bonding methods on both etched and non-etched p...

STATEMENT OF PROBLEM Porcelain fused to zirconia prostheses are widely used. However, porcelain chipping, spalling, fracture, and delamination are common clinical problems. Residual stresses of thermal origin have received attention, but clear data and firing guidelines remain absent. PURPOSE The purpose of this study was to measure the influence of heating and cooling protocols on the streng...

The fluorescence of porcelain crowns recovered from the mouth of an unknown murder victim, and several control porcelain samples, were examined by fluorescent examination lamps. The fluorescence from two of the control samples was quite similar to that from the porcelain crowns recovered from the victim. To increase the objectivity of the results by quantitative analysis, the composition of eac...

Jacket crowns, metal-bonded porcelain crowns and bridges, made by vacuumfiring dental porcelain, have been considered comparatively stable in the oral cavity. In clinical practice, however, stains, slight surface roughness or abraison are sometimes observed on porcelain prosthetic appliances that have been retained for a long time. But studies related to the durability of such porcelain prosthe...

The differentiation of porcelain from tooh using fluorescence emission was investigated as a basic research for the visual detection of porcelain-restored teeth in mass dental health examinations. The fluorescence spectra were taken from the extracted human maxillary central incisors and five types of porcelain by excitation using the light 380-470 nm. There was a clear difference in fluorescen...

Several studies have investigated toughening porcelain that is layered over a frame or a core. The introduction of residual compressive stress to the surface of porcelain has been shown to be effective to strengthen it. In the present study, nanoparticles of precious metals of silver and platinum (rather than non-precious metals) were used to evaluate if they could increase the fracture resista...