Oral parafunctions and association with symptoms of temporomandibular disorders in Japanese university students

TLDR

Further prospective cohort studies, including other potential risk factors, are required to clarify these relationships. The study examined whether oral parafunctions are associated with temporomandibular disorder symptoms in 3,557 Japanese university students aged 18–26. Participants completed a questionnaire on oral parafunctions and TMD symptoms and underwent a dental examination. Among the students, 41.7 % reported TMJ noise, 16.0 % TMJ pain, and 16.3 % impaired mouth opening; sleeping on one side was the most common parafunction (60.2 %), and logistic regression showed that chewing on one side and tooth clenching significantly increased the risk of TMJ noise, pain, and impaired opening (ORs 1.52–2.00).

Abstract

We examined whether oral parafunctions are associated with symptoms of temporomandibular disorders (TMD) in 3557 Japanese university students, aged between 18 and 26 years. Participants completed a questionnaire regarding various oral parafunctions and subjective symptoms related to TMD, and underwent a dental examination. The prevalence of temporomandibular joint (TMJ) noise, TMJ pain and impaired mouth opening was 41.7, 16.0 and 16.3%, respectively. The most prevalent parafunction was sleeping on one side (60.2%), followed by supporting the jaw by leaning on the palm of the hand (44.8%). Mean age, decayed, missing and filled teeth, and number of teeth were not significantly different between TMD positive and negative groups according to unpaired t-test. The chi-squared test revealed that the ratio of females was significantly higher among students with TMD than without TMD. Multiple logistic regression models adjusted for age and gender demonstrated that chewing on one side caused an increased risk of TMJ noise [odds ratio (OR) = 1.52, P < 0.001], TMJ pain (OR = 1.54, P < 0.001), and impaired mouth opening (OR = 2.00, P < 0.001). Tooth clenching also increased the risk of TMJ noise (OR = 1.86, P < 0.001), TMJ pain (OR = 1.79, P = 0.001) and impaired mouth opening (OR = 1.88, P < 0.001). Further prospective cohort studies, including other potential risk factors, are required to clarify these relationships.