A study on the correlations between facial biotype, submentovertex cephalometric measurements and surface EMG activity in patients with facial asymmetry / 대한치과교정학회지

Although the submentovertex radiograph and surface EMG are not often used due to the difficulty of interpretation, they are accepted as useful diagnostic and analytic aids for skeletal asymmetry. There have been reports which state that they were also useful for the evaluation of vertical skeletal relations. The purpose of this study was to evaluate the correlations between EMG data, measurements from submentovertex radiographs, facial types and facial asymmetry following examination of 60 asymmetric patients. The radiographic corpus length were greater in the nonaffected sides (p < 0.001), gonion to interspinosum axis were greater in the affected sides and the mandibular condyle and gonion were located more anteriorly in the non-affected sides than in the affected sides but not significant (p=0.07). The activity of the anterior temporal muscle in rest position was higher in the affected sides than in the non-affected sides (p < 0.01). The activity of the masseter muscle at maximum clenching was found to be nonsignificant but it was higher in the affected sides than in the non-affected sides (p=0.09). There was positive correlation between facial index and the intercondylar axes angle (p < 0.01). There was positive correlation between masseter muscle activity in maximum occlusion and facial index in the affected and non-affected sides (p < 0.05). The results demonstrate that the submentovertex radiograph and EMG can provide useful information for the evaluation of horizontal and vertical skeletal relations.

Submentovertex cephalometric norms in normal adult subjects for diagnosis and evaluation of the prognosis of mandibular condylar fractures

This study was performed to apply the submentovertex cephalometric radiograph to mandibular condylar fractures. Because the left and right structures are not overlaped in the submentovertex radiograph, the dimension and position of mandibular condyle can be clearly identified in this view. The subjects consisted of 40 normal adult patients, twenty healthy males and females with no medical and dental histories. Specific angular and linear measurements were made from each submentovertex radiograph and computerized statistic analysis was carried out. The results were as follows. 1. There was no sexual difference in the angular measurements such as intercondylar angle, angle between condylar axis and mandibular line, and angle between condylar axis and TPA. Though no sexual difference was seen in the linear measurements related to the position of the condyle such as L-TSA, L-TPA, and MSP-Pog, measurements related to the dimension of the condyle such as condylar thickness, condylar width, L-MSP, L-Cpp, MSP-Cpp, and L-Pog were lager in male than female. 2. Statistically, significant difference between right and left values was seen only in the value of condylar width and L-Cpp(p<0.05). But the correlation coefficient of the condylar width between right and left side was very high that it could be thought very useful to compare the left and right side value clinically. 3. In the correlation analysis between left and right side condylar width, L-Cpp, and L-Pog were showed high relation. On the other hand the value of L-TSA was showed low relation. The other measurements were showed relatively high relation. 4. The difference between the maximum and minimum value of each measurement was considerable that the individual variation of measurement was relatively high.