The aim of this study was to investigate the relationship between velocity and factors which could affect the velocity of mandibular movement For this study, 30 dental students without any masticatory signs and symtoms and 90 patients with temporomandibular disorders(TMD) were selected as the control group and the patients group, respectively. After determining Angle´s classification and lateral guidance pattern of occlusion, clinical examination for TMD was performed.
Velocity and distance of mandibular movements were recorded with BioEGN, reprodu ibility index of lateral excursions was evaluated by Pantronic(PRI) and BioEGN(BERI), electivmyographic(EMG) activity in masticatory and cervical muscles were measured with BioEMG, and occlusal contact time and cross-arch imbalance(Total left-right statistics, TLR) on clenching were recorded with T-Scan, respectively. The results of this study were as follows
1. Velocity in the patients was faster than that in the controls in most mandibular movements , but on wide opening and closing movement, result was reverse.
2. Velocity on closing movements were faster than that on opening movements in the control group and a similar tendency was also shown in the patients group.
3. Patients with muscle disorders showed a tendency to have the highest value of velocity of all diagnostic
subgroups, while patients with degenerative joint diseases showed a tendency to have the lowest value
4. Patients with canine guidance showed a tendency to have the highest value of velocity in three subgroups
by lateral guidance pattern, while patients with group function showed a tendency to have the lowest value. 5. BERI had a positive correlation with opening velocity on lateral excursions, while TLR had a negative
correlation with opening velocity on swallowing.
6. EMG activity on clenching in masticatory muscles had negative correlation with opening velocity on border movements, and on swallowing, while the activity in rest correlated positively with opening velocity on border movements.
7. There were positive -con-elation between the velocity and the distance in long components of mandibular trajectory.
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