Comparison of the effect of monolithic and layered zirconia on natural teeth wear: An in vitro study

Abstract

Aim: The aim of this study is to compare wear of the natural teeth against monolithic zirconia and layered zirconia with different surface finishing procedures such as unpolished unglazed, polished unglazed, and polished glazed. Materials and Methods: The two-bodied wear test was carried out in a custom-made oral wear simulator with a sample size of 60 zirconia specimen opposing natural teeth. Zirconia specimen was divided into two groups layered and monolithic which further subdivided into unpolished unglazed, polished unglazed, and polished glazed groups (n = 10). The amount of enamel wear occurred for 250,000 cycles when opposed by monolithic and layered zirconia with different surface finishing methods was measured by loss of height of each tooth using three-dimensional scanning and loss of weight using sensitive balance at specified time intervals of 50,000 cycles during masticatory test considering baseline measurement as control. The data were statistically analyzed to compare the enamel wear against layered and monolithic zirconia with different surface finishing protocols by repeated ANOVA test. Results: Monolithic polished unglazed zirconia showed least tooth wear followed by monolithic polished glazed zirconia, monolithic unpolished unglazed zirconia, and layered unpolished unglazed zirconia showed highest tooth wear in terms of both height loss and weight loss (P < 0.01). Conclusion: Within the limitations of the study, monolithic polished unglazed zirconia is wear-friendly to the opposing natural teeth, and polished surfaces in both the groups showed less tooth wear compared to the glazed surface of zirconia specimen.

Keywords

• Monolithic and layered zirconia
• polished glazed
• polished unglazed
• unpolished unglazed zirconia
• wear