Abstract
The jaw opening reflex was determined in 8 healthy subjects, 11 patients with craniomandibular disorder of type I and another 11 of type II, and the following results were obtained.
1. The degree of mouth opening was significantly lower in type I or type II than in healthy subjects, but no particular difference was found between type I and type II. It was passed judgment on normal (+) in healthy subjects, whereas decline (±) in type I or type II.
2. There was a correlation between the degree of mouth opening and the jaw opening and closing muscles.
3. The temporal muscle activity before stimulation (IBT) was significantly higher in type I than healthy subjects, but there was no particular difference between type II and healthy subjects. Type I and type II showed similar to IBT. The masseter muscle activity before stimulation (IBM) in type I and type II was similar to that in healthy subjects.
4. The temporal muscle activity after stimulation (IAT) and the masseter muscle activity after stimulation (IAM) was highest in type I, followed by type II and healthy subjects in order, with significant intergroup defferences.
5. The IAT/IBT ratio was highest in type I, followed by type II and healthy subjects in order, with significant intergroup difference. The IAM/IBM ratio was significantly higher in type I or type II than in healthy subject, but there was no particular difference between type I and type II.
6. The digastric muscle activity (ID) was significantly lower in type II than in type I or healthy subjects. The ID were similar in type I and healthy subjects.
