Abstract
Aim: This systematic review and meta-analysis aimed to investigate the association between smoking habits and the prevalence of radiolucent periapical lesions (RPLs) in root-filled teeth (RFT). Methods: The Population, Intervention, Comparison, and Outcome (PICO) question was: in adult patients who have RFT, does the absence or presence of a smoking habit affect the prevalence of RPLs associated with RFT? Systematic MEDLINE/PubMed, Wiley Online Database, Web of Science, Scopus, and PRISMA protocol were used to evaluate and present the results. Studies comparing smokers with control non-smoker subjects, including RFT, and providing data on the prevalence of RFT with RPLs, were included. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system was used for certainty in the evidence. The risk of bias was assessed according to Cochrane Collaboration common scheme for bias and ROBINS-I tool. Cumulative meta-analysis was performed with a random effects model. PROSPERO registration code: CRD42020165279. Results: Four studies reported data on inclusion criteria, representing data from 9257 root-filled teeth—4465 from non-smokers and 4792 from smoker patients. The meta-analysis provided an odds ratio indicating a significant association between smoking and higher prevalence of root filled teeth with radiolucent periapical lesions (OR = 1.16; 95% CI = 1.07–1.26; p = 0.0004). The certainty of the literature assessment was moderate per GRADE. The ROBINS-I tool classified three studies as low risk of bias, and the fourth as moderate risk of bias. Conclusions: Moderate, quality scientific evidence indicates a weak but significant relationship between smoking and the prevalence of RPLs in RFT. Smoking can be considered a negative prognostic factor for the outcome of root canal treatment. Endodontic providers should be aware of the relationship between smoking and persistent apical periodontitis, assessed as RPLs, in RFT.
Highlights
Apical periodontitis (AP) is an inflammatory reaction in the periradicular tissues, induced and maintained by bacterial infection of the root canal system [1]
The primary objective of this study was to carry out a systematic review and meta-analysis investigating the possible association between smoking habits and the failure of root canal treatment (RCT), the primary outcome measure being the prevalence of radiolucent periapical lesions (RPLs) in root-filled teeth (RFT)
The clinical Population, Intervention, Comparison, and Outcome (PICO) question to be answered was as follows: in adult patients who have root filled teeth, does the presence or the absence of smoking habits affect the prevalence of RFT with RPLs? PICO (Population, Intervention, Comparison, and Outcome) schema for all the included studies to elaborate upon this research question were used to establish the eligibility criteria as follows: Population: adult patients having root-filled teeth
Summary
Apical periodontitis (AP) is an inflammatory reaction in the periradicular tissues, induced and maintained by bacterial infection of the root canal system [1]. Teeth with AP, when restorable, should be treated with root canal treatment (RCT) [5]. A key goal of RCT is to seal the apical third of the root canal, interrupting the passage of bacterial antigens from the pulp space to the periapical tissues. If this is not achieved, the root-filled tooth continues to show a radiolucent image around its apex, suffers from apical periodontitis [6,7,8], and presents—to some extent and severity—periapical inflammation [9]. Radiographic signs of AP are found in 25 to 61% of asymptomatic RFT [3], not in all cases imply the failure of RCT. The healing after RCT may result in the formation of fibrous tissue composed of dense collagen fibers, few cells, and little or no inflammation, which may be regarded as scar tissue [10]
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