Following treatment of myogenous TMD patients with the temporomandibular opening index: an initial report

Limitation of mandibular movement is one of the cardinal signs of temporomandibular disorders (TMD), usually assessed by measurement of maximum voluntary mouth opening. A new measure of assessing mandibular mobility, the temporomandibular opening index (TOI), is less dependent on variables such as age, gender and ramus length. It has also been found to be useful to categorize patients. This study examined changes in TOI as treatment progressed in a group of myogenous TMD patients. Seven patients with myogenous TMD were included in the study and the TOI determined at 0 and 2 weeks, 1 and 6 months after initiation of treatment. Treatment outcome was assessed on a 4 point scale, 0=none, 1=mild, 2=moderate, and 3=severe. Headache, neckache, pain (joints and muscles) and joint sounds were assessed. Nine patients with no signs or symptoms of TMD were included to obtain a normal TOI. The mean TOI of the patient group was 16.4% (s.d.=11.2%) initially and 3.95% (s.d.=1.0%) at 6 months, while mean treatment scores changed from 12.57 (s.d.=3.05) to 1.43 (s.d.=1.90). The mean TOI of the control group was 3.63 (s.d.=0.74). A paired t -test showed that the TOI decreased significantly with time (P =0.02) while there was a concomitant decrease in treatment score (P =0.0003) over the same period. The TOI may be a useful method of following treatment of this group of myogenous TMD patients.