Comparing metal onlay and full crown in root canal treated molars with single proximal defect - An 18-month clinical study.

Aim: The aim of the study was to compare the survival and success rates of metal onlays and crowns in root canal-treated first and second molars with single proximal defects.

Materials and methods: A total of 120 patients requiring post-endodontic restoration of molars were randomly assigned into two groups (n = 60 each): metal onlays and metal crowns. Restorations were fabricated using standard protocols and cemented with glass ionomer cement. Patients were followed up for 18 months, with survival defined as the presence of an intact restoration and success as the absence of food impaction. To indicate success, revised FDI criteria are used.

Statistical analysis: Kaplan-Meier survival analysis was performed to evaluate the restoration survival rate; the Chi-square test was used to compare categorical variables.

Results: Kaplan-Meier analysis showed a survival rate of 95% for onlays and 90% for crowns, with no significant difference (P = 0.294). Success rates were 91.7% for onlays and 90.0% for crowns with no significant difference (P = 0.604). Food impaction was more common when the pretreatment restoration margin was apical to the cementoenamel junction, though not statistically significant (P = 0.167).

Conclusion: Metal onlays and crowns exhibited comparable survival and success rates in root canal-treated first and second molars with single proximal defects.