Frequency of Tooth Contacting Habit in Patients with Temporomandibular Disorders

Objectives: The aims of this study were to introduce a newly developed recording system for waking-time nonfunctional tooth contact (tooth contacting habit: TCH) and to investigate the frequency of TCH in healthy controls and patients with temporomandibular disorders (TMD) using this system. Methods: This system comprised of specially designed software and a host computer. The software was designed to automatically send an email to subject's cell phone that asks about tooth contact conditions every 20±9 minutes (8:00 A.M. to 9:00 P.M). On the email message subjects select one of the hyper-links that describes various tooth contact conditions, which allow not only to identify the presence of tooth contact but also to differentiate nonfunctional contacts from functional contacts. The selected hyper-link automatically generates a reply email that contains corresponding information, which is sent back to the host computer and stored for the off-line analysis. If the subject does not respond to the email within 120 seconds, this is regarded as non-response. Using this system we recorded the frequency of TCH in 8 healthy subjects and age and gender matched 9 TMD patients for 10 consecutive days. Before the recording, the subjects were asked to fill in Japanese Version of Perceived Stress Scale (JPSS) and Hospital Anxiety and Depression Scale (HADS). Results: Over all response rate of the patient group and the control group was 67.6% and 70.1%, respectively. The frequency of TCH was significantly higher in the TMD patient (median of 29.8% ranging from 17.1% to 57.1%) than in controls (median of 6.4% ranging from 1.0% to 22.8%, P < .01, Mann Whitney U Test). Regarding the frequency of the functional occlusal contact and stress, anxiety and depression status, no significant difference was found between 2 groups. Conclusion: Patients with TMD had more than 4 times more TCH than healthy controls.