교합 접촉 형태에 따른 교근 활성의 평가

Abstract

It have been known that the distribution of EMG activity is determines in a predictavle manner by both the location and number of occlusial contacts. However, these reports placed an emphasis on whole dentition, and there have been few reports of the investigations of the relationship with occlusal contact patterns in the individual tooth. Objectives : The aim of this study was to evaluate the relation between occlusal tooth contact patterns and electromyographical(EMG) activity of masster muscle during maximum voluntary clenching. Materials & Methods : Seven healthy male volunteers (Mean age; 25.3±3 years) were involved in this study. Inclined plane contacts in the frontal plane are classified as A-, B-, or C-types. Acrylic resin overlays were fabricated for upper 1st molars bilaterally and offers 3 types of contact(A-, B-, AB-contact). Thickness of the overlays were dtermined by insertion of leaf gauge(0.3mm thickness) at the central incisiors. Zinc oxide-eugenol paste was used to fit the overlays. EMG activity was recorded bilaterally with bipolar surface electrodes over masseter muscle. Subjects were asked to clench maximally for 3 sec without feeling pain on the teeth or masticatory muscles. The highest value of the EMG activity was selected and the median value of the data of the five trials was used as the representative value. The mean value of right and left masster muscles activity was used as the EMG activity value in each contact type. Statistical analysis was perforned using the Wilcoxon signed-rank test. Results : The group with a B-type contact showed a statistically greater contact(117.4㎶) (P<0.05). Conclusions : These results suggest that the EMG activity of masster muscle during maximum voluntary clenching may very depending on the type of occlusal contact.