Association between Symptoms ofTemporomandibular Disorders and Duration ofComputer Use in a Working Population in Japan

Objective: Visual display terminal work, such as using a personal computer, reportedly causes musculoskeletal symptoms and worsens mental health. Temporomandibular disorders, a type of musculoskeletal disorder, causes symptoms in the temporomandibular joint and masticatory muscles, and is linked to various factors. In this study, we conducted an employee survey to assess the relationship between the time spent working on a personal computer and the odds of reporting temporomandibular disorders-related symptoms. Material and methods: A survey using a questionnaire was administered to employees of 4 companies. The questionnaire’s items addressed temporomandibular disorders-related symptoms, habitual behaviors, psychosocial factors, discomfort when maintaining a space between the upper and lower teeth, and daily personal computer usage time of over 1 h. The subjects were categorized as having temporomandibular disordersrelated symptoms or not having temporomandibular disorder-related symptoms based on their responses to questions on temporomandibular disorders. The relationships between temporomandibular disorders-related symptoms, personal computer usage time, and various contributing factors were analyzed using logistic regression analysis. Results: The final number of subjects selected for the analysis was 4706; of these, 7.6% were categorized as having temporomandibular disorders-related symptoms. Logistic regression analysis showed that using a personal computer for 4 h/day or more was a significant factor of temporomandibular disorders-related symptoms. Conclusions: Our survey assessing the relationship between personal computer usage time and the odds of reporting temporomandibular disorders-related symptoms showed that daily personal computer usage for 4 h or more significantly increased temporomandibular disordersrelated symptoms. This suggests that temporomandibular disorders-related symptoms may be strongly affected by daily personal computer usage, and these symptoms may manifest sooner than other pain-related symptoms, such as headache, neck pain, back pain, or shoulder pain.