Comparision Of Electromyographic (EMG) Activity Of The Masseter, Anterior Temporal Muscles And Mentalis In Various Vertical Facial Types

The objective of the present study is To compare the relationship between electromyographic (EMG) activity of the masseter, anterior temporal muscles and mentalis in different vertical facial types. Clinical examination, cephalometric analysis, and electromyographic examination were performed in 60 volunteers ranging from 16 to 26 years old. The volunteers were classified on the basis of their vertical facial characteristics into three groups- hyperdivergent, normodivergent and hypodivergent-by the grouping analysis.. It was found that the highest mean amplitude was in Group I (416.6 ± 97.1) followed by Group II (389.5 ± 61.3) and the lowest mean value was in Group III (374.6 ± 38.4). Statistical analysis by one-way ANOVA showed that there was no significant difference between Group I, II & III for position ‘P1' in Muscle ‘M1' (P=0.41). The statistical package SPSS (Statistical package for social science, version 4.0.1) was used for statistical analysis. Mean and standard deviation were estimated from the sample. The tests that were used for the statistical analysis were One Way Anova, Multiple Range Test by Tukey- HSD, Students ‘T' Test.In our study, the EMG revealed increased activity of masseter during clenching and increased activity of mentalis during swallowing in hypodivergent group when compared with normo divergentand hyperdivergent group. There was not much difference in muscle activity in the hyperdivergent group.