The purpose of this study was to investigate if there were a significant differences in mandibular position between cephalometric measurements from a centric occlusion tracing compared to those of a acquired centric relation by stabilization splint on malocclusion patient with TMD. 60 malocclusion patients, who had TMD and CO-CR discrepancy beyond normal range, were selected and subdivided into Class I, II, III by Angle´s classification and also subdivided into clockwise, straight downward, and counterclockwise group by Jarabak´s posterior facial height / anterior facial height ratio. Lateral cephaolmetric radiographs with the mandible in centric occlusion were taken and measured, and for each patient the stabilization splint with mutually protected occlusal scheme was applied for minimum 3months. After each patient´s CO-CR discrepancy was in normal range, lateral cephalometric radiographs were retaken and measured. The comparison of the difference between CO-CR cephalometric measurements in all sample, Class I, II, III groups, and Clockwise, Straight downward, Counterclockwise groups were studied.
The finding of this study can be summarized as follows:
1. In all sample, the value of cephalometric measurements was significantly different between CO-CR. The mandible rotated to down and posterior position and the vertical change was greater than the horizontal change (overjet-1.3mm increase, overbite-1.9mm decrease).
2. In Class II malocclusion group, most of the mean difference value between CO-CR is higher than that of the other groups and more measurements was statically significant.
3. In clockwise and counterclockwise group, some of the mean difference value is higher than that of straight downward group and more measurements was statically significant.
4. There ware no measurements that explain centric relation measurements from the type of malocclusion, facial pattern and centric occlusion measurements.
Henceforth, it is strongly recommended that stabilization splint therapy for orthodontic treatment on TMD patient should be excuted upon overall facial types prior to orthodontic diagnosis and treatment planning.
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