Abstract
Objectives
To evaluate the five-year clinical performance of CAD/CAM lithium disilicate overlays placed on endodontically treated molars, analysing tooth survival, restoration survival and restoration success as separate endpoints.Materials and methods
Ninety-three overlays placed between 2016 and 2021 were identified; 63 in 59 patients attended recall and were analysed. One operator performed all procedures. Every tooth had been treated for irreversible pulpitis without periapical radiolucency. Tooth survival was retention of the tooth (extraction as the event), restoration survival retention of the original restoration, and restoration success freedom from any intervention; nonsurgical retreatment was a separate tooth-level event. Two calibrated examiners graded performance with the revised FDI criteria before any intervention (weighted kappa > 0.90). Outcomes were estimated with the Kaplan-Meier method.Results
Sixty-two of the 63 evaluable restorations were in function at five years (mean follow-up 5.1 years). Two tooth-level events occurred at 24 months, both endodontic: one extraction and one retreatment through the overlay. Five-year tooth survival was 98.4% (95% CI 89.3-99.8) and survival free of endodontic re-intervention 96.8% (95% CI 87.9-99.2). No restoration was replaced or lost (restoration survival 100%). Seven interventions were performed between 12 and 60 months: four refinishing, two composite repairs and one endodontic access. Kaplan-Meier restoration success was 88.8% (95% CI 77.9-94.5), or 90.4% excluding the endodontic access. No restoration was graded 5 in any category.Conclusions
Lithium disilicate overlays provided predictable coronal coverage of endodontically treated molars over five years. Both tooth-level events were endodontic rather than restorative, indicating that restorative and biological outcomes behave as separate endpoints.Clinical significance
Overlays may offer a conservative alternative to full crowns for endodontically treated molars with sufficient residual tooth structure. Reporting restoration survival and restoration success separately gives clinicians a more realistic picture of the maintenance such restorations are likely to require.