Complications of endodontically treated abutment teeth after restoration with non-precious metal double crowns

Objectives This study aimed to evaluate the effects of endodontic treatment on the complication rate in abutment teeth following double crown treatment. Materials and methods Data of 233 patients supplied with 278 prostheses on 773 teeth were retrospectively analyzed. The 60-month cumulative complication rate for vital, root filled, and post and core reconstructed abutment teeth is calculated using the Kaplan-Meier method. Cox regression is performed to evaluate factors including age, sex, jaw, and tooth number. Results After 60 months, the cumulative complication rate for all abutment teeth was 24.1% (CI: 19.7-28.5%). A significantly higher cumulative fracture rate (log-rank test,p< 0.001) was found for devital (51.7%; CI: 35.3-68.1%) compared to vital abutment teeth (20.6%; CI: 16.2-25%). Devital teeth restored with post and core reconstructions (46.3%; CI: 26.1-66.5%) showed a lower cumulative fracture rate than abutment teeth with only root fillings (60.9%; CI: 33.5-88.3%). Abutment teeth in severely reduced dentitions (<= 3 teeth) were found to have significantly lower survival rates than abutment teeth in not severely reduced dentitions (>= 4 teeth,p= 0.031, HR = 0.609). Conclusion Lower abutment teeth survival rates were associated with non-vitality and a reduced number of abutment teeth. Devital teeth with post and core reconstructions showed higher survival rates than root filled devital teeth.