The Measurement Of The Morphology And Structure Of The Temporomandibular Joint In Patients With The Unilateral Posterior Crossbite By Using CBCT

Purpose:The unilateral posterior crossbite is common in orthodontic clinics. This type of patients are often accompanied with the deflecting open,the joints ringing, the twisted locked and the mouth-opening limited and so on. In this study,we used CBCT (Cone Beam Computed Tomography) to scan the bilateral temporomandibular joints in patients with Angle class I and the unilateral posterior crossbite, used Cybermed OnDemand 3D software to measure the related parameters with the morphological structure. The skeletal morphology and structure of the bilateral temporomandibular joints(TMJ)of the patients who were Angle class I was compared with those who had the unilateral posterior crossbite Jearned whether the gender and age could have some effect on the development of the TMJ,made us further explore whether the unilateral posterior crossbite will affect the bilateral morphology and position of the TMJ. Methods:1.According to the strict inclusion criteria and exclusion criteria, selected 14 cases (the number of the TMJ:28.gender:male 6 cases,female 8 cases.age:from 12 to 30 years old,including 6 cases under the age of 20 and 8 cases over the age of 20,the average age was 20.50±6.073 years)accompanied with the unilateral posterior crossbite as the experimental group and 15 cases(the number of the TMJ:30.gender:male 7 cases,female 8 cases.age:from 11 to 31 years old,including 6 cases under the age of 20 and 9 cases over the age of 20,the average age was 21.20±6.372 years) as the control group.All object were from orthodontic department in the hospital of stomatology affiliated to Luzhou Medical College from September,2012 to December,2014.2. All patients were scanned by CBCT in the ICP then use the Cybermed OnDemand3D software to reconstruct the reference planes (the sagittal and axial plane,the corrected coronal and sagittal plane).Some indexes were measured on the selected reference planes and included the radius(R) and condylar length(CL)of the TMJ on the axial plane;the articular horizontal slope(β), the articular eminence heigh(AH),the condylar length(CL),the articular fossa width(LE)and articular fossa depth(HI);the condylar major axis(CMl)on the corrected coronal plane;the condylar minor axis(CM2)and the joint space on the corrected sagittal plane and used the Pullinger analysis to analyze the relative position of the condylar within the articular fossa(LR). Each data was measured three times by the experimenter himself and took the average.The all results of experiment were statistically analyzed with the software of SPSS20.0. The data were expressed by M±SD(x±s), the available range was 95% and the bilateral alpha was 0.05(a=0.05).The left and right side of the control group, the crossbite and normal side of the experimental group both used the paired t test;the crossbite side of the experimental group and the control group,the normal side of the experimental group and the control group,the patients under the age of 20 and patients over the age of 20 in the experimental group used the independent samplet test.Results:1.There were no statistical differences in skeletal morphology of TMJ among the patients in man and woman of two groups(P>0.05).2.The morphological structure and the position of the bilateral TMJ of the control group had no statistical significance (P>0.05).3.Compared the crossbite side with the normol side in the experimental group,there were significantly statistical differences (P< 0.01)among the articular horizontal slope,the condylar length(CL)and the superior and posterior space of the joint; there were statistical significance(P< 0.05) among the condylar major axis(CMl),Condylar minor axis(CM2)and the anterior joint space.4.Compared the crossbite side of the experimental group with the control group, the condylar Length(CL) had significantly statistical significance (P<0.01); the condylar major axis(CMl)and the anterior joint space had statistical significantly (P<0.05) Compared the normol side of the experimental group with the control group, the posterior space of joint had statistical significance(P＞0.05).5.Compared the crossbite side of teenagers with adults, in the experimental group,the condylar length(CL) had statistical significance(P<0.05).Compared the normal side of teenagers with adults, in the experimental group,there were statistical significance(P<0.05) among the condylar length(CT),the articular fossa width(LE),the articular fossa depth(HI)and the condylar minor axis(CM2);there were obviously statistical significance(P<0.01)among the superior, posterior,anterior space of the joint. 6.Compared the crossbite side with the normal side of the experimental group in teenagers, there were statistical significance (P<0.05) among the articular horizontal slope,the articular fossa depth(HI) and the anterior space of the joint; there were significantly statistical significance (P＜0.01) among the superior, posterior space of the joint. And the relative position of the condylar within the antirior fossa. Compared the crossbite side with the normal side of the experimental group in adults, the articular horizontal slope had statistical significance (P<0.05);there were significantly statistical significance (P< 0.01) among the condylar length(CL),the condylar major axis(CMl)and the condylar minor axis(CM2).Conclusion:1.Gender had no effect on the morphology and structure of the TMJ.2.The structure of the TMJ had morphological difference in patients with the unilateral posterior crossbite.3.The morphology of the bilateral TMJ in adolescent was symmetrical,but the relative position of the condylar was different. The relative position of the TMJ in adults was symmetrical,but the morphology of the bilateral TMJ was not symmetrical. As the age increasing, the morphology and structure of the TMJ had changed.