Sliding contact fatigue of graded zirconia with external esthetic glass

Veneer chipping and fracture are common failure modes for porcelain-veneered zirconia dental restorations. we hypothesized that the graded glass/zirconia/glass with external esthetic glass (e-gzg) can increase the lifetime and improve resistance to veneer chipping and fracture relative to porcelainveneered zirconia,while providing necessary esthetics. previously,we have demonstrated that a graded glass-zirconia surface possesses excellent resistance to occlusal-like sliding contact fatigue. here,we investigated the sliding contact fatigue response of this graded glass-zirconia surface with external esthetic glass. this external glass is essential for shade options,for preventing excessive wear of opposing dentition,and for protecting y-tzp from hydrothermal degradation. e-gzg plates were bonded to composite blocks and subjected to prolonged sliding contact up to 10 million cycles at 200 n in water. the resistance to sliding contact fatigue of e-gzg matches that of monolithic y-tzp,and both of these materials demonstrated lifetimes that were orders of magnitude longer than that of porcelain-veneered zirconia. graded e-gzg is a promising restorative material. © 2011 international & american associations for dental research.