Change in horizontal mandibular position after gothic arch tracing in edentulous patients

点击翻译按钮获取中文摘要

The purpose of this experiment was to investigate whether the practice of tracing gothic arch influence the condylar position in edentulous patient. Results were the following.Three healthy males in the twenties were selected. The anterior and bilateral border movement and the tapping movement of the mandible were recorded by mean of the K3DMS2 system with 6-degrees of freedom, and a program that can analyzed quantitatively the gothic arch and the tapping point was developed. The program was able to display the mandibular movement during gothic arch tracing, and at the same time the length of the anteriorly and bilaterally traced path, the border angle, the overlapping of tapping point over the gothic arch traced path, the average point of the ten tapping points, its positional coordinates, standard deviation, and coefficient of variation.For the six edentulous patients the anterior and bilateral border movement and the tapping movement of the mandible were recorded, and the bite was recorded at the apex of gothic arch (record A). Then the subjects were asked to trace gothic arch repeatedly till making clearly apex, and the bite was recorded (record B). The condylar positions for the record A and the record B were recorded using a tomography. The length of anterior and bilateral border movement for the record B was significantly longer than that for the record A. The maximal diameter of tapping points for the record B was significantly smaller than that for the record A. The condylar displacement index for the record B was significantly smaller than that for the record A.From these results it was suggested that the practice of tracing gothic arch brought about expansion of mandibular movement, stability of tapping movement, and improvement of condylar position in edentulous patient.