This study was performed to investigate the reproducibility of eccentric mandibular movements according to preferred chewing side, range of mouth opening, type of lateral guidance and involvement of temporomandibular disorders. 50 patients with temporomandibular disorders and 65 dental students without any signs and symptoms were randomly selected for this study as the patients group and the control group, respectively.
For recording and observation of eccentric mandibular movement trajectory, BioEGN® of Biopak® system (Bioresearh Inc., USA) was used. Each eccentric movement to anterior, right and left side was performed three times similar to the movement pattern for Pantronic Reproducibility Index. Mandibular path was analyzed by three dimensional positional change and the three paths fmxtr one direction were coned with one aAother. From this, reproducibility index of one-directional lateral movement could be calculated, and total reproducibility index, named BioEGN reproducibility index(BERD, was also computed from three-directional eccentric movement likewise. BioEGN reproducibility index could have four value of score by small or large scale, and by outgoing or incoming movement.
The data were analyzed by SAS/stat program and the results obtained were as follows
1. Right side chewing subjects showed more consistent pattern in reproducibility index in comparison between patients group and control group than left chewing subjects have done, and reproducibility was low in patients group. However, there was no difference between the two groups in bilateral chewing subjects.
2. There were no difference in reproducibility index between preferred chewing side and contralateral side in unilateral chewing subjects whereas reproducibility index in left side on outgoing movement were higher than in right side in bilateral chewing subjects.
3. Difference iii total reproducibility index(BERI) between canine guidance group and non-canine guidance group were
not observed though difference in reproducibility index on lateral movement were observed in part
4. There were no difference in reproducibility index between affected side and contralateral side in unilaterally affected
patients, and between unilaterally affected patients and bilaterally affected patients in patients group.
5. Highly significant positive correlationship were shown among the four types of total reproducibility index(BERI)
in total subjects, and range of clinical mouth opening was negatively correlated with BERI on outgoing movements
and with index on outgoing movement to preferred side.
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