Relationships between self-rated oral health, subjective symptoms, oral health behavior and clinical conditions in Japanese university students: a cross-sectional survey at Okayama University

BACKGROUND Self-rated oral health is a valid and useful summary indicator of overall oral health status and quality of life. However, few studies on perception of oral health have been conducted among Japanese young adults. This study investigated whether oral health behavior, subjective oral symptoms, or clinical oral status were associated with self-rated oral health in Japanese young adults. METHODS This cross-sectional survey included 2,087 students (1,183 males, 904 females), aged 18 and 19 years, at Okayama University, Japan. A self-administered questionnaire was distributed and an oral examination was performed. RESULTS In a structural equation modeling analysis, the score of decayed, missing and filled teeth (DMFT) significantly affected self-rated oral health (p <0.05) and the effect size was highest. Malocclusion, subjective symptoms of temporomandibular disorders (TMD) and stomatitis, and poor oral health behavior significantly induced self-rated poor oral health with small effect sizes (p <0.05). Clinical periodontal conditions and Oral Hygiene Index-simplified were not related to self-rated oral health. CONCLUSION Self-rated oral health was influenced by subjective symptoms of TMD and stomatitis, oral health behavior, the score of DMFT, and malocclusion. The evaluation of these parameters may be a useful approach in routine dental examination to improve self-rated oral health in university students.