The effect of the gonial angle, ramus length, age and gender on the temporomandibular opening index.

Linear mouth opening is often used to assess the limitation of mandibular movement. However, this has a number of limitations. It is dependent on variables such as age, gender and ramus length. A new measure of movement has been developed previously, called the temporomandibular opening index (TOI). Forty-two subjects who did not exhibit signs and symptoms of temporomandibular disorder (TMD) were recruited to this study. The relationship of age, gender, gonial angle, ramus length and the TOI was studied. Linear regression analysis showed that the TOI was not dependent on gender (P > 0.644), gonial angle (P > 0.327), ramus length (P > 0.248) and age (P > 0.690). The index may therefore be a better measure of mandibular movement.

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.

The temporomandibular opening index (TOI) in patients with closed lock and a control group with no temporomandibular disorders (TMD): an initial study.

Mandibular movement may be assessed by measuring maximum mouth opening. This is a linear measurement from the maxillary to the mandibular incisal edge and is affected by gender, age and ramus length. It cannot be used to classify patients. The temporomandibular opening index (TOI) appears to be independent of these variables and has been shown to differ for different categories of patients with temporomandibular disorders (TMD). This study examined the TOI in a group of 11 patients with closed lock and a control group of 11 individuals with no signs or symptoms of TMD. The group with closed lock had a significantly different TOI from that of the control group (P < 0.001) according to the Mann-Whitney U-test. This suggests that the TOI may have greater diagnostic value than linear mouth opening.

Myogenous temporomandibular disorder patients and the temporomandibular opening index.

Limited mandibular movement is one of the cardinal signs of temporomandibular disorders, and is usually assessed by measurement of mouth opening. Linear measurement of mouth opening does not discriminate between diagnostic groups and has been shown to be influenced by gender, age and ramus length. A new temporomandibular opening index, however, can differentiate between diagnostic groups and is not influenced by the above variables. When patients with a myogenous temporomandibular disorder were examined, the temporomandibular opening index distinguished two subgroups, the first with values about the lower quartile and the second with values about the upper quartile. A similar identification of two subgroups was seen in electromyographic studies of myogenous temporomandibular disorder patients.