Three-dimensional Measuring Study Of Temporomandibular Joint And Its Surrounding Accessory Structure

Objective:To measure 12 indexes of temporomandibular joint(TMJ)glenoid fossae,roots of zygoma,condyle and ramus units etc.,compare the symmetry of TMJ in both side and the correlation of glenoid fossae and condyle in same side,which aims to design the TMJ structure matched to the affected side of patients by means of the relationship of two sides in reference of the anatomic data of TMJ in uninjured side computer aided design and 3D printing technology when the anatomy of TMJ in one side is largely damaged as comminuted fracture,ankylosis of temporomandibular joint,severe osteoarthritis so as to improve the matching between prosthesis and tissue structure,providing the reference to the design of prosthesis of whole temporomandibular joint for the local region.To compare the difference of TMJ between males and females,and try to seek for the reason of high morbidity of TMD in females.Material and Methods:Picking up the maxillofacial CT data from 200 patients in non-maxillofacial diseases as cervical spondylosis,cerebrovascular disease and etc.of People’s Hospital of Donge,60 cases(120 cases of normal TMJ)of maxillofacial CT data are selected for the research in accordance with inclusion criteria and exclusion criteria,with the averageage of 40 to 60.There are 34 males with average age of 52.4 and 26 females with average age of 50.3.All CT data is imported into the software of Simplant Pro 11.04(Materialize,Belgium)in the form of DICOM for the 3D reconstruction.The locating points in the 3D reconstruction model are set synchronously by one oral and maxillofacial surgeon,one orthodontic doctor and one medical imaging doctor based on the anatomical features and established 3D measurement standard.The choosing of points in each model is subject to 4 aspects including coronal position,axial position,head-shadow side position and 3D reconstruction.12 indexes running high correlation with the size and relative position of glenoid fossae,condyle and ramus units are measured,in which 5 items are about the glenoid fossae and its surrounding relevant structure;7 items about the condyle and its surrounding structure.Paired t is adopted for the test and comparison difference in two sides of 12 indexes,and independent simplet is adopted for the test and comparison of gender difference on the front and rear radius,inside and outside radius of glenoid fossae and condyle,and the height of condyle.P<0.05 is considered statistically significant.Results:1.The measurement result of 12 indexes of this research conforms to normal distribution.There are no statistically significant differences in both sides(P>0.05).2.By means of the comparison of front and rear radius,inside and outside radius of glenoid fossae and condyle,the ratio conforms to normal distribution.The front and rear radius of glenoid fossae is 1.2 times of that of condyle.The ratio of inside and outside radius of condyle and glenoid fossae is approximately 1.06.The radius of condyle is slightly bigger than glenoid fossae.3.As for the comparison between males and females of front and rear radius,inside and outside radius of glenoid fossae and condyle,height of condyle,the inside and outside radius of glenoid fossae and condyle have no statistical significance(P>0.05).The gender differences in front and rear radius of glenoid fossae and condyle,height of condyle is statistically significant(P<0.05).Conclusion:1.The structure of temporomandibular jointin left and right side of the adults with normal temporomandibular joint.2.There are large differences of individual TMJ among the adults with normal temporomandibular j oint.3.There is a tight correlation between the glenoid fossae and the form and size of condyle in same side among the adults with normal temporomandibular joint.4.There is a kind of difference between males and females on the temporomandibular joint and its surrounding accessory structure among adults.The glenoid fossae and condyle of males is slightly bigger than females’.5.The data of temporomandibular joint and its surrounding bony structure will be accurately acquired in terms of the computer auxiliary design software.