A clinical comparison of internal joint disorders in patients presenting disk-attachment pain: prevalence, characterization, and severity of bruxing behavior.

This study clinically documents the presence of disk-attachment pain (DAP) related to the severity of bruxism and to the prevalence of internal joint disorders in patients and controls. The sample consisted of 394 temporomandibular disorder (TMD) and bruxing behavior patients and 104 nonbruxer control subjects. The TMD group was subdivided in a group of 109 disk-attachment pain patients and 285 bruxing behavior-nonDAP groups. The second reference group was a sample of 104 nonbruxing behavior subjects. Comprehensive evaluations (including history of signs and symptoms), use of questionnaires, clinical examination, palpation of muscles and joints, classification of bruxing behavior by the degree of severity, and diagnostic tests were performed in patients and controls. There was a prevalence of disk-attachment pain in the group of TMD and bruxing behavior patients. The degree of jaw opening was lower in the DAP group as compared to the TMD/bruxism-nonDAP group and controls. The mean Visual Analog Scale (VAS) value for the joint pain complaints was slightly elevated in the DAP group as compared to the TMD/bruxism-nonDAP group. Specific masticatory disorders including difficulties to open, pain on opening, chewing pain, fatigue on chewing, jaw deviation to opening, and change to a soft diet, were significantly more prevalent in the DAP group as compared to the other reference groups. Our conclusions are based upon a review of the literature and on the results of this study: a. DAP is a relatively well defined stage of internal joint derangement (IJD); and b. compared to other groups, DAP patients as a subgroup are relatively more impaired by their masticatory and other functional disorders. This study provides strong support to other studies and demonstrates that DAP is a well-differentiated and severe internal joint disorder.