In Vitro Wear of Human Enamel Against Monolithic Zirconia After Staining, Glazing and Polishing Treatments.

Objective: To evaluate the effect of staining, glazing, and polishing of stabilized zirconia with 5 mol% of yttrium oxide (5Y-TZP) on the wear behavior of opposing tooth enamel.

Materials and methods: The plane specimens of 5Y-TZP were divided into 6 groups (n = 10), according to surface treatment: as sintered, staining, glazing, polishing, staining followed by glazing, and staining followed by polishing, and positioned against tooth enamel during the two-body wear test (20 N, 2 Hz, until completing 300,000 cycles). The wear rates of tooth enamel were evaluated using a profile projector and a digital pachymeter as a measure of vertical height loss. The data were analyzed by one-way ANOVA and a Tukey post hoc test (α = 0.05).

Results: Polishing reduced the vertical height loss (p < 0.001) while there was no difference among other groups.

Conclusion: Polishing is recommended as a finishing procedure to reduce the wear rates of tooth enamel, and finishing procedures (glazing or polishing) performed after staining did not affect the vertical height loss of tooth enamel.

Clinical significance: Polishing is the recommended finishing procedure for preshaded 5Y-TZP to reduce the wear rates of opposing tooth enamel. Staining is applied to the occlusal surface to reproduce the pigmented groove appearance, and glazing or polishing performed after staining did not affect the wear rates of opposing tooth enamel.