[Functional study of the temporomandibular joint in new orthodontic cases using the hinge axis recorder].

The temporomandibular joint function of 66 children (mean: 11.5) with malocclusion was investigated with help of axiographic tracings. Besides other parameters of the tracings we studied the relationship between centric occlusion, centric relation and their positions in regard to the axiographic tracing line of the protrusion movement with a gauge between the front teeth. The distance between CR and CR measured as a vector was 0.7 mm (+/- 0.4 mm). Though we investigated a group with serious malocclusions the distance of CO measured perpendicular to the gauge protrusive tracing was 0 (+/- 0.4 mm). In 60 joints the CO tracing point did not coincide with the gauge protrusive line: On account of these measurements the terms compression and distraction of the joint have a graphic meaning. In 4% of the children we found tracings which were typical for joint pathology: reciprocal clicking. In 21% of the patients we found "disturbed" tracings, but their prognostic value is still unknown.