A CBCT Comparative Study On Condylar Position And Glenoid Fossa Morphology Of Different Sagittal Skeletal Pattern In Patients

Objective:The aim of this study was to investigate the difference on condylar position and glenoid fossa morphology of different sagittal skeletal patients with high angle by CBCT and Invivo Dental5.1 software.Methods:60 cases(male 30, female 30,mean age 18.883±1.427 years old) of high angle patients(SN-MP angle of >38°) were chosen as the research object in the Dalian Stomatology Hospital from 2013 January to 2014 December.Their clinical data was complete, CBCTimage data acquired in the same way. Criteria of the cases:(1)17-21 years old, sex ratio 1:1(2)high angle: SN-MP, angle >38°(3) no orthodontic and orthognathic history(4)no obvious mandibular and facial asymmetry(5) no obvious joint symptoms(6) CBCT showed no obvious temporomandibular joint pathological change.According to the measuring mean of Chinese normal occlusion by Steiner analysis method, patients were divided into three groups:class I、class II、class III(each group had 10 male cases, 10 female cases).Patients were scaned by Ka Vo Ka Vo3 De Xam cone beam tomography system of American Ka Vo Company in the same conditions.Patients sitting, the Frankfort plane was parallel to the ground, fixed natural head position, and the patients’ head midline was consistent with CBCT scanning equipment’s midline.All the patients were scaned in the same condition, obtaining the 3-D images. TMJ analysis of the Invivo Dental5.1 was used to analysis the condylar position and glenoid fossa morphology in three dimensions. In order to avoid measurement errors all the parameters were measured three measurements by the same person and then take the average value.A total of 60 patients were measured and 120 sets of data were obtained,All of the data was analyzed by spss19.0 software. The Kolmogorov-Smirnov test was performed on the left and right side measurement data of the condyle measurements to confirm normal distribution.Then the paired t test analysis was used. When the data was homogeneity of variance, among the different groups were performed LSD-t test method.Only P<0.05 was considered statistically significant.Results:Class II patients’ left joint’s anterior space is smaller than the right;left articular tubercle posterior slope angle and the glenoid fossa depth were higher than the right side, the difference was statistically significant(P<0.05).Class III pati ents’ left articular fossa depth were higher than the right side, the difference was statistically significant(P<0.05). Class I patients’ and class III patients’ anterior space were smalle r than class II patients’, the difference was statistically significant(P<0.05). C lass I patients’ and class II patients’ posterior space were smaller than Class III patients’.The width and depth of the glenoid fossa were smaller than Class III patients’ and the posterior slope angles of the articular eminence were great er than the class III patients’. The difference was statistically significant(P<0.05). In this experiment 80% c lass I patients’ condyles are concentric in the glenoid fossa, 77.5%class II patients’ condyles showed posterior position, 75% class III patie nts’ condyles showed anterior position.Conclusion:1.The right and left condyles are basically symmetry. 2. C lass III patients’ articular fossa were much wider and more shallow than the class I and class II patients’.3.Morphology of articular fossa are highly relevant to the depth of articular fossa and the inclination of the glenoid fossa. 4. Most class I patients’ condyl es were concentric in the fossa, most class II patients’ condyl es showed posterior position and most class III patients’ condyles showed anterior position.