Two-Year Clinical Evaluation of Enamel Wear Antagonistic to Polished and Glazed Monolithic Zirconia Endocrowns.

Objective: To assess the effect of chairside adjustment and polishing on the clinical performance of zirconia endocrowns and digitally calculate the opposing enamel wear.

Materials and methods: A total of 20 participants received zirconia endocrowns on their endodontically treated lower first molars. All endocrowns were fabricated using CAD/CAM technology. According to the occlusal adjustments needed for the restorations, patients were divided into two groups: Group ZG with 10 glazed monolithic zirconia endocrowns and Group ZP with 10 adjusted and polished zirconia endocrowns. Bonded endocrowns were evaluated clinically and radiographically for 24 months following modified FDI criteria. Wear of the antagonistic enamel was calculated at 6, 12, 18, and 24 months using an intraoral scanner and Geomagic software.

Results: The overall survival rate of the 20 endocrowns was 100%, according to the Kaplan-Meier survival method. None of the endocrowns were replaced during the follow-up. After 2 years, polished zirconia caused enamel wear (0.422 ± 0.130 mm³), while glazed zirconia caused enamel wear (0.491 ± 0.105 mm³), with no statistically significant difference (p = 0.108).

Conclusion: Both glazed and polished monolithic zirconia endocrowns showed comparable enamel wear after a 2-year clinical follow-up, with no significant difference.

Clinical significance: Glazing or intra-oral polishing could be applied to monolithic zirconia endocrowns with minimal antagonist enamel wear.