Background Bruxism is a prevalent repetitive jaw-muscle activity that generates occlusal forces capable of acting as a chronic irritant on the dentino-pulpal complex and the periodontal supporting tissues. Its specific influence on the prognosis of endodontic treatment has been scarcely investigated. This study analysed the association between a clinical diagnosis of untreated bruxism and the outcome of root canal treatment in a retrospective clinical cohort, exploring possible interactions with systemic, anatomical and demographic factors. Methods A retrospective observational cohort study was conducted in 551 patients treated in the Master’s Degree Programme in Advanced Endodontics at CEU San Pablo University (Madrid) between 2006 and 2009, with a minimum follow-up of one year. One index tooth was analysed per patient. Bruxism was diagnosed clinically by a single examiner. Treatment outcome was classified as success or failure following the criteria of the European Society of Endodontology. Associations were assessed with Pearson’s chi-square test; unadjusted odds ratios and relative risks with 95% confidence intervals were calculated where cell counts were available, and the Benjamini-Hochberg correction was applied for multiple comparisons. The study followed the STROBE guidelines. Results In systemically healthy patients, the success rate was 93.3% (95% CI 87.4–96.6) without bruxism and 78.3% (95% CI 70.1–84.8) with untreated bruxism, a difference of 15.0% points (χ² = 32.054; p = 0.015; crude OR for failure 3.87, 95% CI 1.67–8.96). Pulp necrosis was associated with a lower success rate (82.3% vs. 92.1%; p = 0.001). Single-rooted index teeth showed better outcomes than molars (94.4% vs. 82.8%; p = 0.002). Patients aged 17–40 years had the highest success rate (93.5%), and sex was not associated with outcome (p = 0.638). Associations involving systemic-disease subgroups were based on small samples and are reported as exploratory. Conclusions A clinical diagnosis of untreated bruxism was associated with a lower success rate of root canal treatment, an association that appeared more pronounced in the presence of certain systemic conditions. Given the retrospective design and the absence of adjusted analysis, these findings should be interpreted as associations requiring confirmation in prospective studies. They nonetheless support incorporating bruxism assessment into the diagnostic evaluation of endodontic patients.

Influence of untreated bruxism on root canal treatment outcome: a retrospective cohort study of 551 patients

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2026年7月1日

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Alejandra De la Rosa Rico

摘要

Background

Bruxism is a prevalent repetitive jaw-muscle activity that generates occlusal forces capable of acting as a chronic irritant on the dentino-pulpal complex and the periodontal supporting tissues. Its specific influence on the prognosis of endodontic treatment has been scarcely investigated. This study analysed the association between a clinical diagnosis of untreated bruxism and the outcome of root canal treatment in a retrospective clinical cohort, exploring possible interactions with systemic, anatomical and demographic factors.

Methods

A retrospective observational cohort study was conducted in 551 patients treated in the Master’s Degree Programme in Advanced Endodontics at CEU San Pablo University (Madrid) between 2006 and 2009, with a minimum follow-up of one year. One index tooth was analysed per patient. Bruxism was diagnosed clinically by a single examiner. Treatment outcome was classified as success or failure following the criteria of the European Society of Endodontology. Associations were assessed with Pearson’s chi-square test; unadjusted odds ratios and relative risks with 95% confidence intervals were calculated where cell counts were available, and the Benjamini-Hochberg correction was applied for multiple comparisons. The study followed the STROBE guidelines.

Results

In systemically healthy patients, the success rate was 93.3% (95% CI 87.4–96.6) without bruxism and 78.3% (95% CI 70.1–84.8) with untreated bruxism, a difference of 15.0% points (χ² = 32.054; p = 0.015; crude OR for failure 3.87, 95% CI 1.67–8.96). Pulp necrosis was associated with a lower success rate (82.3% vs. 92.1%; p = 0.001). Single-rooted index teeth showed better outcomes than molars (94.4% vs. 82.8%; p = 0.002). Patients aged 17–40 years had the highest success rate (93.5%), and sex was not associated with outcome (p = 0.638). Associations involving systemic-disease subgroups were based on small samples and are reported as exploratory.

Conclusions

A clinical diagnosis of untreated bruxism was associated with a lower success rate of root canal treatment, an association that appeared more pronounced in the presence of certain systemic conditions. Given the retrospective design and the absence of adjusted analysis, these findings should be interpreted as associations requiring confirmation in prospective studies. They nonetheless support incorporating bruxism assessment into the diagnostic evaluation of endodontic patients.