Temporomandibular disorders among smokers and nonsmokers: a longitudinal cohort study

To evaluate whether smoking influences the presence and/or development of signs and symptoms of temporomandibular disorders (TMD) among adults.

A random sample of subjects 35, 50, and 65 years of age was drawn from the general population and examined with the aid of a questionnaire and a clinical examination. Within the sample, smokers were identified based on reported current smoking and nonsmokers were matched to the smokers based on age, gender, educational level, area of residence, and number of teeth. In total, 268 subjects were matched (134 pairs). Six years after the baseline examination, 122 matched pairs were re-examined.

Mild symptoms of TMD were reported by approximately 30% of the sample both at baseline and at the follow-up examination 6 years later. Pain in the jaws and/or more severe symptoms of TMD were reported by approximately 15% on both occasions. No significant differences between smokers and nonsmokers were found regarding symptoms of TMD. In both examinations, mild signs (dysfunction index I) were found in approximately 40% of the sample and moderate to severe signs (dysfunction index II to III) in approximately 20%; no statistically significant differences were found between smokers and nonsmokers. No significant differences were found between smokers and nonsmokers regarding the course of symptoms or signs of TMD during the study period.

Smoking is not a factor related to the presence or development of signs and symptoms of TMD.