Restoring that are teeth endodontically treated through existing crowns. Part IV: Material usage and prevention of dye leakage

Objective: This study was undertaken to determine if any materials in clini cal use can prevent coronal leakage when used to restore endodontic access openings in permanently fixed crown restorations. Method and materials: Nin ety-six teeth were allocated to 1 of 8 complete-coverage crown groups. Endo dontic access openings were made through the crowns and restored with 1 of 5 restorative modalities. Methylene blue dye was placed in the coronal rese rvoir of each assembly of a leakage assessment apparatus for 30 days. Teeth were embedded in methylmethacrylate, sectioned, and computer scanned. Thre e calibrated, independent examiners assessed computer-projected Views with a predetermined scoring system. Results: The overall difference between the material-crown margin and the crown-tooth margin indicated more leakage on the latter, but the difference was not statistically significant. Porcelai n-covered crowns showed greater leakage, but no statistically significant d ifference was found among crown types. Glass-ionomer restorations had highe r leakage values, but there was no statistically significant difference amo ng materials. Conclusion: Coronal leakage at the material-crown margin is s ubstantial when endodontic access openings are restored in complete-crown r estorations that have undergone nonsurgical root canal therapy.