Long-term tooth survival and success following primary root canal treatment: a 5- to 37-year retrospective observation

Abstract

Objectives: The aims of the present longitudinal retrospective observational case series study were to investigate the survival and success rates of primary non-surgical endodontic therapy.

Materials and methods: Patients with at least one endodontically treated tooth (ETT), with 5 years of follow-up and in compliance with the recall programme of at least 1 time per year in a private practice setting, were recruited. Kaplan-Meier survival analyses were performed considering (a) tooth extraction/survival and (b) endodontic success as the outcome variables. A regression analysis was performed to evaluate prognostic factors associated with tooth survival.

Results: Three hundred twelve patients and 598 teeth were included. The cumulative survival rates showed 97%, 81%, 76% and 68% after 10, 20, 30 and 37 years, respectively. The corresponding values for endodontic success were 93%, 85%, 81% and 81%, respectively.

Conclusions: The study demonstrated high longevity in symptomless function as well as high success rates of ETT. The most significant prognostic factors associated with tooth extraction were the presence of deep (> 6 mm) periodontal pockets, the presence of pre-operative apical radiolucency and the lack of occlusal protection (no use of a night guard).

Clinical relevance: The favourable long-term (> 30 years) prognosis of ETT must encourage clinicians to rely on primary root canal treatment when taking the decision regarding whether a tooth with pulpal and/or periapical diseases should be saved or be extracted and replaced with an implant.

Keywords: Endodontic success; Endodontic treatment; Long term; Primary root canal treatment; Tooth survival.

Fig. 1

(a), Tooth 2.5. pre-op periapical radiograph, year 1979. (b), Periapical radiograph after endodontic and restorative treatment with cast metal post and crown, year 1979. (c), Post-op periapical radiograph follow-up, year 2004. (d), Post-op periapical radiograph demonstrating success 37 years after primary endodontic treatment , year 2016. (e) Tooth 4.6. pre-op periapical radiograph, year 1982. (f), Periapical radiograph after endodontic treatment, year 1982. (g), Tooth 4.6. post-op periapical radiograph with restorative treatment with a fiber post and radiolucent composite material and a crown, follow-up year 2000. (h), Tooth 4.6. post-op periapical radiograph demonstrating success after 34 years follow-up, year 2016. (i), Tooth 4.4. pre-op periapical radiograph, year 1979. (l), Periapical radiograph after endodontic treatment, year 1979. (m), Post-op periapical radiograph follow-up with restorative treatment, year 2004. (n), Post-op periapical radiograph demonstrating survival in painless function 37 years after primary endodontic treatment, year 2016.

Fig. 2

Flow chart of patient inclusion in the study

Fig. 3

Kaplan–Meier function curves of 598 endodontically treated teeth. (a) Survival and (b) Endodontic Success

Fig. 4

Kaplan–Meier function survival curves based on tooth position

Fig. 5

Kaplan–Meier function survival curves (a) comparing patients using (green line) or not using (blue line) the night guard, (b) comparing teeth with (green line) or without periapical radiolucency (blue line) and (c) comparing teeth with 1-3 mm PPD (blue line), 4-5 mm PPD (green line) and > 6 mm PPD (yellow line)