| Objective: Facial symmetry is one of the important indicators for judging the beauty.The growth of the face which is influenced by both genetic and environmental factors,is a long process.Facial asymmetry is ubiquitous and its patterns is complex.Some patients with severe mandibular deviation have a uniform deviation of the mandibular body and the ramus.However,some mandibular deviations,especially to a lesser extent,are complicated.There are compensation and/or decompensation among parts of the mandible.In this study,we tried to make analysis of the mandibular of patients who were mild facial asymmetry by CBCT data to find the characteristics and regularity of mandibular structure.Methods: The 60 study objects were selected from the department of Orthodontics in Hospital of Stomatology,Hebei Medical University,from January 2017 to October 2017.Seven orthodontic postgraduates were selected to judge whether there was facial asymmetry by the positive image of these patients.20 patients had been selected,if there were more than 5 graduates who believe that a patient has face asymmetry and his menton is less than4 mm away from the mid-sagittal plane.Pre-treatment CBCT scans were obtained in the intercuspal position(ICP).The raw data was saved as digital imaging and communications in medicine(DICOM)files and imported into Invivo software.Skeletal and dental landmarks were set on the 3D reconstructed models to conduct linear?angle and volume mesurements in mandible.Statistical analysis was made with SPSS21.0 software.Significance level was set at 0.05.Result:1.Mean of the menton(Me)'s deviationThe mean Me-MSP in patients with mild facial asymmetry was 1.91±1.09 mm.2.Measurement of the LinearsThe height of the condyle was 16.98±2.59 mm on the nondeviated side and 17.99±2.37 mm on the deviated side(P<0.05).The nondeviated side was less than the deviated side,and the length of the mandibular body was84.66±5.64 mm on the nondeviated side and the deviated side was83.38±4.69mm(P<0.05).The nondeviated side was greater than the deviated side;the height of the mandibular bodywas 27.91± 2.85 mm on the nondeviated side,with deviated side was 28.69±2.77mm(P<0.05),the nondeviated side was less than the deviated side;The width of the ramus was37.34±3.43 mm on the nondeviated side,with deviated side was36.48±3.50mm(P<0.05).The nondeviated side was greater than the deviated side;the Go-Cor plane was 72.12±5.88 mm on the nondeviated side and70.80±6.51 mm on the deviated side(P<0.05),the nondeviated side was greater than the deviated side;the lenth of the ramus was 56.84±4.70 mm on the nondeviated side,and the deviated side was 58.11± 5.67mm(P<0.001),the nondeviated side was smaller than the deviated side.There was no statistical differences in the rest measurements(P>0.05).3.Angle measurement resultsThe nondeviated side of the mandibular angle was 117.16±6.67° and the deviated side was 115.93±6.53°(P<0.05).The nondeviated side was greater than the deviated side.The POP on nondeviated side was 13.84±5.31°,and the deviated side was 12.30±4.56°(P<0.05).The nondeviated side was greater than the deviated side;There was no statistical differences in the angle between the condyle and coracoid(P>0.05).4.Volume measurement resultsThe nondeviated side of the mandibular body volume was 23898.21±4477.86mm3,and the deviated side was 22305.10±4867.31mm3(P<0.001).The nondeviated side was greater than the deviated side;There was no statistically significant difference in the other measurements(P>0.05).Conclusion:1.There is a certain degree of complementation between the mandibular ramus and the body of patients with mild facial asymmetry,that is,the nondeviated side mandibular body has more growth than the deviated side,which is opposite in the ramus.While the length and volume of the mandible on the left and right sides are almost the same size.2.The main reason of the mentum deflection in patients with mild facial asymmetry is the mandibular body. |
PDF Full Text Request