Tobacco smoking and its impact on pain intensity of temporomandibular disorders: A systematic review and metanalysis

Background: Temporomandibular disorders (TMDs) encompass a spectrum of orofacial conditions characterised by pain and dysfunction in the temporomandibular joint and surrounding structures. Tobacco smoking has been posited as a potential factor influencing the prevalence and intensity of TMD. However, the nature and extent of this relationship remain unclear due to variations in study outcomes. This systematic review aimed to consolidate existing research findings to elucidate the association between tobacco smoking and TMD pain intensity. Methods: A comprehensive search of electronic databases was conducted to identify relevant studies published up to June 2023. Studies investigating the relationship between tobacco smoking and TMD pain were included. Data extraction was conducted by two reviewers. Quality assessment was performed using the New Castle-Ottawa scale. Review Manager 5.4 was used to quantitatively analyse the results. Results: The review included four studies employing similar TMD assessment techniques. All studies reported elevated TMD pain intensity among tobacco users, with non-smokers exhibiting lower pain intensity. The quality of the included studies was good. Meta-analytic results showed that TMD pain intensity was higher in the smokers group compared to the non-smokers group, with a weighted mean difference (WMD) of 0.65 (BPM) (95% CI: [0.10, 1.19], p =.02). Conclusion: This systematic review provides a comprehensive synthesis of the existing literature on tobacco smoking and TMD symptoms. The findings underscore the multifaceted nature of the relationship between smoking and TMD pain, highlighting its clinical relevance and the need for tailored interventions. Further research is warranted to elucidate underlying mechanisms and potential moderating factors, contributing to a more nuanced understanding of this complex association.