Does tobacco smoking predispose to apical periodontitis and endodontic treatment need? A systematic review and meta‐analysis
Authors: Pinto K. P. , Ferreira C. M. , Maia L. C. , Sassone L. M. , Fidalgo T. K. S. , Silva E. J. N. L. 
Published: April 2020

Background

Controversial findings exist in the literature regarding the association between tobacco smoking and development of apical periodontitis or need for root canal treatment, with some studies reporting an increase in the prevalence of these outcomes in smokers, whilst others reporting no association.

Aim

To evaluate if there is scientific evidence to support an association between tobacco smoking and a greater prevalence of apical periodontitis and/or root canal treatments.

Data Sources

A systematic search was performed using MeSH terms and free terms in the PubMed, Scopus, Virtual Health Library (VHL), Cochrane library and Open Gray databases.

Study Eligibility Criteria, Participants and Interventions

Observational studies that evaluated the association between smoking and the development or healing of periapical lesion and/or the prevalence of root canal treatment in humans were included.

Study Appraisal and Synthesis Methods

A quality assessment of included studies was performed, and the relevant information and findings were evaluated. A meta‐analysis using nine included studies was performed through RevMan software, and the certainty of evidence was evaluated through GRADE.

Results

Fifteen studies were included, of which 10 were classified as low risk of bias, 4 were considered as moderate risk of bias and 1 as high risk of bias. Ten studies reported that smoking was associated with a greater prevalence of periapical periodontitis and/or root canal treatment. Five studies reported no association. Nine studies were included in the pooled meta‐analysis, comprising two subgroups: apical periodontitis and root canal treatment. From these nine studies, eight studies were included in the apical periodontitis subgroup meta‐analysis and demonstrated that this condition was significantly more prevalent in smokers when compared to the nonsmokers (odds ratio = 2.78[CI: 1.60, 4.85], P < 0.001; I2 = 79%; no adjusted odds ratio). Three studies were included in the root canal treatment subgroup meta‐analysis and demonstrated an increased prevalence in smokers when compared to the nonsmokers (odds ratio = 2.73 [CI: 1.06, 2.83], P < 0.001; I2 = 72%; no adjusted odds ratio). The pooled meta‐analysis demonstrated that smokers had twice the chance of having apical periodontitis and/or root canal treatment when compared to nonsmokers (odds ratio of 2.42 [CI: 1.59, 3.68], P < 0.01; I2 = 85%). The GRADE analysis demonstrated moderate certainty of evidence.

Limitations

Several confounding factors were identified such as misinformation regarding the period of time subjects had smoked, as well as the frequency of smoking and the number of cigarettes consumed. No adjustment in odds ratio data for confounding was performed.

Conclusions and Implications of Key Findings

This systematic review and meta‐analysis indicate that tobacco smokers have an increased prevalence of periapical periodontitis and root canal treatments with moderate certainty of evidence.