Due to elastic modulus mismatch between the different layers in all-ceramic dental restorations, high tensile stress concentrates at the interface between the ceramic core and cement. In natural tooth structure, stress concentration is reduced by the functionally graded structure of dentin-enamel junction (DEJ) which interconnects enamel and dentin. Inspired by DEJ, the aim of this study was to...

BACKGROUND To evaluate the influence of thermal and mechanical fatigue on the shear bond strength of different all-ceramic cores and veneering porcelain interfaces. MATERIAL AND METHODS All-ceramic systems tested were lithium disilicate and zirconia veneered by layering technique. Sixty specimens (n=20) were subjected to shear bond strength. Ten of them were thermal and mechanical cycled. Fra...

A study is made of veneer failure by cracking in all-ceramic crown-like layer structures. Model trilayers consisting of a 1 mm thick external glass layer (veneer) joined to a 0.5 mm thick inner stiff and hard ceramic support layer (core) by epoxy bonding or by fusion are fabricated for testing. The resulting bilayers are then glued to a thick compliant polycarbonate slab to simulate a dentin ba...

objectives: masking ability of a restorative material plays a role in hiding colored substructures; however, the masking ability of zirconia ceramic (zrc) has not yet been clearly understood in zirconia-based restorations. this study evaluated the effect of three different core materials on masking ability of a zrc. materials and methods: ten zirconia disc samples, 0.5mm in thickness and 10mm i...

A fiber made by Furnace CVD was codoped with Erbium and Magnesium using a Flash Vaporization System for the first time. The fiber core is spontaneously formed as a Transparent Glass Ceramic (TGC). Due to the small nanoparticle size (<50 nm) and high volumetric density (10~10 m), the optical loss due to scattering is as low as < 0,6 dB/m. Erbium ions are highly concentrated within phase-separate...

STATEMENT OF PROBLEM Surface-finishing protocols have a mechanical impact on ceramic surfaces that could eventually affect surface topography and light scattering. An optimum protocol is needed to avoid damaging the optical properties of ceramics. PURPOSE The purpose of this study was to determine the effects of different surface-finishing protocols on the surface roughness, color change, and...

Background: This study aimed to assess the fracture resistance of zirconia restorations fabricated with rapid layer (RL group) technique and zirconia computer-aided design/computer-aided manufacturing (zir/CAD/CAM) system (ZC group). Methods:This study evaluated 30 all-ceramic crowns in two groups of 15. After fabricating the metal dies and scanning them ...