Relationship between type A behavior patterns and risk of temporomandibular disorder in Japanese undergraduate students

Objective: Several studies have demonstrated the relationship between temporomandibular disorder (TMD) and emotional stress. Nonetheless, few surveys have examined the relationship between type A behavior patterns and TMD. The aim of this study was to clarify the relationships among TMD, type A behavior patterns, bruxism, and emotional stress in Japanese undergraduate students. Methods: This study was undertaken in Nayoro City, Japan, in 2015, among students of Nayoro City University. The survey was conducted through an anonymous, self-administered, multiple-choice questionnaire. Information was gathered on items evaluating the extent of TMD symptoms, bruxism, type A behavior patterns, and proneness and sensitivity to emotional stress. Results: The questionnaire recovery rate was 31.8% (175/551). There was a high likelihood of TMD in 16.1% of respondents, which is comparable to the findings of previous surveys on Japanese high school students. In keeping with previous studies, we confirmed significant relationships between TMD and both emotional stress and bruxism. A weak but statistically significant association was found between TMD and type A behavior patterns. Conclusion: We propose that TMD may be one of the diseases related to the type A behavior pattern.