Tooth wear against ceramic crowns in posterior region: a systematic literature review

The objective of this systematic review was to assess tooth wear against ceramic crowns in posterior region in vitro and in vivo. An electronic PubMed search was conducted to identify studies on tooth wear against ceramic crowns in posterior region. The selected studies were analyzed in regard to type of crowns, natural antagonist, measuring protocol and outcome. From a yield of 1 000 titles, 43 articles were selected for full-text analysis; finally, no in vitro and only five in vivo studies met the inclusion criteria. As there is heterogeneity in design, used measuring method, ceramics and analysis-form, a meta-analysis was not possible. Results of these studies are very controversial which makes a scientifically valid comparison impossible. This review indicated that some all-ceramic crowns are as wear friendly as metal-ceramic crowns. Up to now, it has been impossible to associate tooth wear with any specific causal agent. The role of ceramic surface treatment that might be responsible for the changing in rate of tooth wear seems undetermined as yet through clinical trials. The literature reveals that studies on this topic are subject to a substantial amount of bias. Therefore, additional clinical studies, properly designed to diminish bias, are warranted

Clinical factors affecting the translucency of monolithic Y-TZP ceramics

The use of monolithic yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics in aesthetically critical regions is questionable because of the insufficient translucency and opacity of the restorations. Intrinsic (manufacturing process) and extrinsic factors (laboratory procedures and clinical factors) can affect the translucency of monolithic zirconia. In this narrative review, the clinical factors (thickness, cementation type, colour of the monolithic zirconia, surface finishing methods and wear, dental background, cement colour, low temperature degradation) affecting the translucency of monolithic Y-TZP ceramics were reported