Methods: A retrospective cohort study model of patients having received primary endodontics at Sydney Dental Hospital between January 1996 and December 2001 was carried out. Over 7000 patients were identified and 571 patient files were randomly selected for review with specific inclusion and exclusion criteria determining eligibility. Treatment details, clinical and radiographic assessment at review from time of treatment were recorded to assess outcome at least 8 years after treatment. Kaplan-Meir and Cox regression analyses determined overall success, survival and failure.
Results: One-hundred and sixty-two teeth (121 patients) were included. At review 129 teeth (80%) were retained and 33 teeth (20%) were lost/failed due to endodontic complications with radiographic assessment showing 104 (64.5%) with evidence of healing (success), while 25 teeth (15.5%) showed evidence of disease (survival). Statistically significant differences were observed by operator, with 93% of specialist-teeth treated surviving at 8 years compared with 77% of generalist-treated teeth. Eighty-percent of maxillary anteriors and posteriors survived compared to 82% of mandibular anteriors and 77% of mandibular posteriors. Survival rates for teeth restored with full coverage were 90% compared with 79% of teeth restored with a metallic restoration and only 73% of teeth restored with an adhesive restoration. A significant difference in the failure rate of smokers compared with non-smokers was found, 45% and 15% respectively.
Conclusion: Approximately 80% of teeth survived at least 8 years following endodontics, with 64.5 % of teeth found to be disease free (success). Operator, tooth position, final restoration and patient smoking were found significant in affecting the outcome.