Abstract
A prospective cohort study was conducted on healthy volunteers with no current or past history of temporomandibular disorder (TMD) in order to identify psychological factors that contribute to the condition.
TMD is most common in patients aged in their twenties. This study was, therefore, performed with the cooperation of 207 freshmen (139 males and 68 females, average age of 20.4 years) of Iwate Medical University Dental School. At the start and 5 years later, all subjects were requested to fill out a questionnaire on mandibular functions together with the psychological questionnaires of CMI, SDS, MAS, Y G. The incidence of TMD symptoms was evaluated after 2.5 years and again after 5 years by self-reported questionnaire.
129 subjects completed the study over the whole 5 years. They included 32 (19 males and 13 females) who were experiencing pain in the tempromandibular joint and/or masticatory muscle and/or mouth opening problems at the times of the 2.5-year and 5-year follow up surveys.
Logistic regression analysis was performed to identify intrinsic factors. It produced an odds ratio (OR) of 2.65 (95% CI=1.07-6.56) and adjusted OR of 7.00 (95% CI=1.45-33.79) in Y-G. These results imply that emotional instability may be a contributory factor to TMD.
