Reproducibility of jaw movements in patients with craniomandibular disorders

It has never been investigated, if mandibular movements of patients with craniomandibular disorders (CMD) result in a lower reproducibility of dynamic functional parameters which are used for the individual articulator setting. The aim of the present study was to compare the reproducibility of electronically registered functional parameters in patients with CMD and in a control group. Dynamic functional parameters were recorded in 30 patients and 30 volunteers with a computerized ultrasound system (ARCUSdigma). The whole registration was performed three times during one session and three times at a second session 1 week later. The horizontal condylar inclination in the patient group gave a standard deviation of 2.17 degrees +/- 0.95 degrees , indicating poorer reproducibility than in the volunteer group, for which the standard deviation was 1.37 degrees +/- 0.42 degrees . The reproducibility of measurements of the Bennett angle was also poorer in the patient group than in the volunteer group, with standard deviations of 1.70 degrees +/- 0.62 degrees and 1.22 degrees +/- 0.40 degrees , respectively. The standard deviations calculated for determination of incisal inclination during laterotrusion was 3.02 degrees +/- 1.49 degrees for patients and 2.30 degrees +/- 1.17 degrees for volunteers. The standard deviations for incisal inclination during protrusion was 2.02 degrees +/- 0.95 degrees for patients and 2.06 degrees +/- 1.82 degrees for volunteers. The reproducibility of measurement of horizontal condylar inclination, Bennett angle and incisal inclination during laterotrusion therefore showed significantly lower reproducibility in the patient group than in the volunteer group (P < 0.05). The overall reproducibility of the measurements was nevertheless good in both groups, with standard deviations under 3.1 degrees , so that an individual setting of an articulator seems useful even in patients with CMD.