The Study On Age-related Change Of TMJ’s Bony Structure By Using CBCT

Objective:To analyze the measurements of bony structure of temporomandibular joint (TMJ) of different ages by cone beam computed tomography(CBCT), compare of the differences between the groups, investigate and quantify the relationship between morphology, location and age, and provide a reference for the discrimination between age-related changes and pathological changes.Methods:Based on the TMJ imaging and measurement technique,92TMJs of46healthy subjects were selected(Group of teenagers:age of14-18,10subjects; Group of youth: age of19-40,20subjects; Group of middle age: age of41-59,9subjects; Group of elderly: age of above60,7subjects) and scanned by CBCT. Choose the interested region to reconstruct the image of bony structure of TMJ at axial view, oblique position paralled to the long axis of condyle, oblique position vertical to the long axis of condyle. Parameters that could reflect TMJ skeletal morphology and location were taken in the multi planar reformation(MPR) and were analysed by SPSS software.Results:1.There was significant difference in altitude of condylar process, posteroanterior and medialateral diameter of condylar process, posteroanterior and medialateral diameter of glenoid fossa between Group of teenagers and Group of youth(P<0.05), the Group of teenagers was lower;2.No significant differences were found between Group of youth and Group of middle age(P>0.05); but there is the same changing tendency in posteroanterior and medialateral diameter of condylar process, posteroanterior and medialateral diameter of glenoid fossa, transverse inclination of condylar lateral-medial axis, depth of glenoid fossa, anterior inclination of the mandibular fossa, the angle between anterior mandibular fossa and poster mandibular fossa, superior space between Group of youth and Group of middle age and between Group of middle age and Group of elderly;3.There was significant difference in posteroanterior and medialateral diameter of glenoid fossa between Group of middle age and Group of elderly(P<0.05), the Group of elderly was lower;4.There was significant difference in posteroanterior and medialateral diameter of condylar process, posteroanterior and medialateral diameter of glenoid fossa, depth of glenoid fossa, transverse inclination of condylar lateral-medial axis, the angle between anterior mandibular fossa and poster mandibular fossa between Group of youth and Group of elderly(P<0.05), the Group of elderly was lower; There was significant difference in anterior inclination of the mandibular fossa, superior space between Group of youth and Group of elderly(P<0.05), the Group of elderly was larger.Conclusions:1.Through this study, we obtained the normal measurement results of TMJ bone structure and location in all age groups;2.Size of TMJ was larger in youth than teenagers; size of TMJ was lower in middle age than youth; size of TMJ was lower in elderly than middle age.3.Size of condyle was smaller than size of fossa in different age groups; a tendency of the changes were the same in both sizes of condyle and fossa with increasing age, they were satisfactory adaptive;4.The depth of glenoid fossa in the middle age was lower than youth; the depth of glenoid fossa in elderly was lower than the middle age;5.The anterior inclination of the mandibular fossa in the middle age was larger than youth; the anterior inclination of the mandibular fossa in elderly was larger than the middle age;6.The superior space in the middle age was larger than youth as the decrease of condylar process; the superior space in elderly was larger than the middle age.