Three-Year Clinical Outcomes of Lithium Disilicate and Lithium-Silicate-Modified Zirconia Veneers and...

Background: Clinical evidence regarding lithium-silicate-modified zirconia veneers and partial-coverage restorations remains limited. This retrospective study compared the observed three-year outcomes of two complete adhesive restorative protocols rather than the isolated effects of ceramic materials. Materials and Methods: One hundred ceramic veneers and partial-coverage restorations placed in eleven patients were evaluated after a three-year follow-up. Fifty restorations were fabricated from lithium disilicate (IPS e.max Press; Ivoclar Vivadent AG, Schaan, Liechtenstein), and fifty were fabricated from zirconia (Aidite Biomedical Co., Ltd., Qinhuangdao, China) treated with the Biomic LiSi Connect system. No patient received both protocols. Clinical records, photographic documentation, and recall examinations were reviewed for fractures, chipping, marginal discoloration, surface wear, secondary caries, hypersensitivity, repairs, replacements, and debonding. Outcomes were analyzed descriptively because multiple restorations were clustered within patients and protocol allocation followed clinical indication. Wilson 95% confidence intervals (CIs) were reported for restoration-level proportions as descriptive measures and were not adjusted for clustering. Results: Both protocols showed 100% survival without replacement (95% CI: 92.9-100.0%). Debonding affected 6/50 zirconia restorations (12%; 95% CI: 5.6-23.8%) and 0/50 lithium disilicate restorations (0%; 95% CI: 0.0-7.1%). The six events occurred in five of seven zirconia patients and none of four lithium disilicate patients. All debonded restorations were recemented and remained functional. No fractures, chipping events, repairs, or replacements were recorded. Conclusions: No replacement or structural failure was observed during three years in this selected convenience cohort. However, the zirconia protocol had six retention-related interventions. Because the protocols differed in material, surface treatment, cement, indication, and anatomical distribution, the findings are exploratory and do not establish an isolated material effect.