Cone-beam Computed Tomography Measurement And Analysis Of Skeletal Structure Of Temporomandibular Joint In Patients With Unilateral Chewing And Tempromandibular Joint Disorders

Objective: The aim of this study was to investigate the effect of unilateral chewing on the morphology and spatial position of the temporomandibular joint,CBCT was used to measure the changes of TMJ bone structure in patients of TMD with unilateral chewing.Methods: Forty patients with TMD who have been unilaterally chewing for a long time and twenty bilateral healthy temporomandibular joints were selected as controls,from November 2017 to December 2018,he was admitted to the temporomandibular joint clinic of the Stomatological Hospital of Zunyi Medical University.CBCT was used to scan the craniofacial region of all subjects with the large field of view and rebuild the 3D images,then the reconstructed images were corrected and the measurement plane was chosen.The anteroposterior diameter of the condyle,the mediolateral diameter of the condyle,radius value and the horizontal angles of condyle could be obtained at the axial position of the largest long axis of the condyle,the force angle of condyle,the vertical angle of condyle and the medical,lateral joint space could be obtained at the oblique view paralleled to the long axis of condyle,the width of glenoid fossa,the depth of glenoid fossa,the inclination of articular eminence,the anterior,superior,posterior joint space,the thickness of condylar neck and the height of condyle could be obtained at the oblique view perpendicular to the long axis of condyle.All measurements data were analyzed by the SPSS 22.0 statistical software.Results:The results showed that there were no significant differences between the dimensions of bilateral structures of the TMJ in the control group(P>0.05).However,the inclination of articular eminence of the preferred side was less than that of the unpreferred side in participants with unilateral chewing(P<0.05);the condylar height of the preferred side was greater than that of the unpreferred side in participants with unilateral chewing(P< 0.05).The anteroposterior diameter of the condyle,medical joint space,posterior joint space,the thickness of condylar neck of the preferred side in participants with unilateral chewing were smaller than the control group(P<0.05);the anterior space of the preferred side in participants with unilateral chewing was greater than the control group(P <0.05).The anteroposterior diameter of the condyle,the inclination of articular eminence,the thickness of condylar neck of the unpreferred side in participants with unilateral chewing were smaller than the control group(P<0.05);the anterior joint space of the unpreferred side in participants with unilateral chewing was greater than the control group(P<0.05).Conclusion: The bilateral TMJ bone structure of patients with unilateral chewing and TMD has different degrees of change;the bilateral condyles size reconstruction becomes smaller in the sagittal direction under abnormal stress,the prefered condyle shifts inward and backward,anterior space of the unperferred aide joint have compensatory increase,Whether they are invetable factors leading to TMD symptoms needs further clarification.