Abstract
The purpose of our study was to elucidate the influence of the lateral mandibular deviation (LMD)on the mastication in children with deciduous dentition by evaluating the difference of the jaw muscle activities between the side of deviated mandibles and that of the other side.
The subjects were 9 children with deciduous dentition. The side of The LMD was measured on posteroanterior plain skull radiographs.
All through this study, the subjects were instructed to perform three jaw motor tasks, tooth clenching, tooth tapping and gum-chewing on both impaired and intact side. Temporal (TA) and Masseter (M) muscles electromyograms were recorded on the bilateral sides to observe the jaw muscle activities.
The balance of the mastication muscle activity during clenching tasks was assessed using the Asymmetry Index (A. I. ). The activity of the TA proved more dominant on the deviated side, while that of the M tended to be more remarkable on the contalateral side.
In the gum-chewing on the contralateral side, both the activities of M and TA showed more significant increase than during the tooth tapping task (p<0.05). In this case, however, no significant difference was observed between the chewing task and tooth tapping task on the deviated side of TA (p>0.05).
Conclusion: in spite of marked muscle activity during the clenching task, dysfunction of TA on the deviated side during gum-chewing was suggested to occur, probably due to influence of mandibular deviation which leads to an impaired feedback system of oral sensation.
