Direct Resin Composite and Lithium Disilicate Endocrowns in Severely Compromised Endodontically Treated Molars: A Two‐Year Randomized Controlled Trial

AIM: This randomized controlled superiority trial aimed to compare the clinical performance (restoration survival, clinical quality, and patient satisfaction) of direct resin composite and lithium disilicate endocrown restorations in structurally compromised endodontically treated molars. The null hypothesis stated that there would be no significant difference in clinical performance after 2 years. METHODOLOGY: This was a prospective, randomized superiority controlled trial (ClinicalTrials.gov: NCT06934460). A total of 102 asymptomatic, endodontically treated, and severely structurally compromised molars referred to a university clinic for restorative treatment were included. Teeth were randomly assigned to receive either a direct microhybrid resin composite restoration (n = 51) or a lithium disilicate endocrown in conjunction with immediate dentine sealing (n = 51). Restoration quality was assessed clinically using Fédération Dentaire International (FDI) criteria at 1 week and at 3, 6, 12, and 24 months. The primary outcome measure was restoration survival (FDI score ≤ 4). Secondary outcomes included abutment tooth survival (extraction of the tooth, regardless of the cause) and abutment tooth success (defined as the absence of tooth extraction, endodontic pathology, or the need for non-surgical or surgical endodontic retreatment). Patient satisfaction was assessed using a questionnaire over the first year. Kaplan-Meier estimates were used for survival analysis. Restoration quality and satisfaction were compared using Mann-Whitney U, Chi-squared, and Friedman's ANOVA with Bonferroni corrections (α = 0.05). RESULTS: Cumulative restoration survival rates were 98.0% (95% CI: 87.0%-100.0%) and 100.0% for direct resin composite and lithium disilicate endocrowns respectively (p = 0.32). Tooth survival was 100.0% in both groups. Indirect endocrowns showed superior surface lustre, wear resistance, and mucosal health after 24 months. Patient satisfaction was similar in both groups. CONCLUSIONS: Both restoration types performed well in restoring severely structurally compromised endodontically treated molar teeth after 24 months. Lithium disilicate endocrowns showed better performance in surface lustre, wear resistance, and mucosal health. However, these qualitative differences did not translate into differences in patient satisfaction, indicating that both restorative options were perceived as equally acceptable by patients in the short-term.