Further treatments of non-surgically root canal-treated teeth in public dental service: A long-term register-based study

Objectives: Our objective was to assess further restorative treatments, extractions and endodontic retreatments registered for root canal-treated teeth (RCTT) in a 13- to 15-year follow-up at Public Dental Service (PDS), and to examine the association of the frequency of further treatments with patient-, tooth-, and operator-related factors.

Methods: Data were collected from electronic patient records of the Helsinki PDS. Based on dental treatment codes, teeth with registered primary non-surgical root canal treatments (nsRCTs) (n = 16 954) between 2002 and 2004 were followed until the end of 2016. Estimation of incidence of further treatments was calculated with generalized linear model. Cox regression model was conducted to estimate the influence of patient-, tooth- and operator-related factors of the primary nsRCT for further restorative treatments, extractions, or endodontic retreatments.

Results: Further restorative treatments were the most often carried out treatments (38.2%) for RCTT, followed by extractions (19.5%), non-surgical retreatments (4.8%) and surgical retreatments (0.5%). Endodontic retreatments were often registered within few years of the primary nsRCT while the frequency of extractions remained nearly constant over the years. Younger age, anterior teeth, and teeth with indirect coronal restorations were mostly associated with lower incidence of further treatments.

Conclusion: Our study demonstrated that RCTT were registered with mainly further restorative treatments after primary nsRCT. One-fifth of teeth were extracted during the study period, while endodontic retreatments were uncommon. Placement of indirect restoration was associated with lower incidence of further treatments, within the limitations of this study.

Clinical significance: Knowledge of further treatments that root canal-treated teeth may require is highly important for both dentists and patients. Identification of risk factors that could have influence on further treatments after primary non-surgical root canal treatment should be part of the treatment planning to ensure favorable outcomes.

Keywords: Dental care; Endodontics; Public health practice; Root canal treatment.