Comparative Wear of Opposing Natural Enamel by Different Ceramic Materials in Fixed Dental Protheses: A Systematic Review and Meta-Analysis

Background/Objectives: This systematic review aimed to quantify the extent of wear of opposing posterior natural enamel in patients with single-unit ceramic crowns. Methods: A comprehensive search was conducted in PubMed/MEDLINE, Embase, Web of Science, Cochrane Library, and ProQuest through September 2025. A meta-analysis was performed using the inverse variance method. Results: Nine clinical studies (5 randomized controlled trials and 4 prospective studies) involving 203 patients (2015–2025) were included. All studies evaluated monolithic zirconia; two also assessed monolithic lithium disilicate, and three included metal-ceramic restorations with feldspathic veneering. Follow-up ranged from 6 to 24 months. Meta-analysis revealed significant enamel wear from zirconia (p < 0.05; MD: −1.32; 95% CI: −2.06 to −0.57; I2 = 94%) and lithium disilicate (p < 0.05; MD: −0.45; 95% CI: −0.71 to −0.19; I2 = 2%). Feldspathic ceramics did not show significant enamel wear (p = 0.06; MD: −2.77; 95% CI: −5.66 to 0.13; I2 = 96%). Conclusions: Ceramic materials generally cause greater wear on opposing posterior natural enamel than enamel-to-enamel contact. Monolithic zirconia and lithium disilicate crowns produced higher antagonist wear, whereas metal-ceramic restorations with feldspathic veneering appeared more conservative for preserving posterior enamel.