Objective: To compare the central nervous system processing of orofacial pain patients who might have atypical pain (group 1) after occlusal treatment with those patients who had synovitis pain of temporomandibular disorders (TMD) (group 2).
Methods: Seven patients in each group were included in this study. Ten painless normal subjects (group 3) were employed as a control group. Functional magnetic resonance imaging (fMRI) was used to observe the activation of the brain evoked by clenching. The fMRI data were treated statistically as the result of each group.
Results: The main active regions of three groups were different. The main active regions of the group 1 were bilateral thalamus and anterior cingulate cortex. The group 2 activated a quite different pain network, including postcentral gyrus, cingulate gyrus and prefrontal cortices.
Conclusions: The pain network is different between the two groups of pain patients and the pain network is more sensitive in atypical pain patients than in synovitis pain patients.