The Area Feature Of Temporomandibular Joint And Its Association With Anterior Disc Displacement

ObjectiveDuring our clinical study,we found a possible relationship between the displacement of temporomandibular joint disc and the size of mandible condyle.The purpose of this study is to determine the relationship between temporomandibular joint anterior disc displacement and the area of the oblique sagittal section of mandible condyle and glenoid fossa.MethodsTake 134 random patients came to the first Affiliated Hospital of Zhejiang University shooting magnetic resonance image between 2016 and 2017 into consideration.The age ranges from 20 to 40.Select 33 normal cases,30 cases of unilateral temporomandibular joint anterior disc displacement,23 cases of bilateral temporomandibular joint anterior disc displacement.The area of mandible condyle and glenoid fossa in the sagittal section was analyzed and measured,calculate the area ratio of condyle-fossa.(1)Compare the data of the sick side with the healthy side with paired sample t-test and non-parametric test.(2)Using independent sample t test tool to analyze the data of normal TMJ samples and anterior disc displacement TMJ samples,to testify whether there was a significant different between them.(3)Analyze the correlation between the data of TMJ in the sagittal section and TMJ anterior disc displacement by using Stratified chi-square test.(4)Using independent sample t test tool to analyze the data of condyle area and fossa area in the sagittal section of normal TMJ samples and the normal side of ADD patients,to testify whether there was a significant difference between them;using non-parametric test to testify if there was a significant difference between their condyle-fossa ratio in the sagittal section.Results(1)For the cases of the unilateral anterior disc displacement,the area of affected condyle in the sagittal section was significantly lower than the normal side(p<0.05);\there was no significant difference between the area of glenoid fossa of affected and normal side in the sagittal section(p>0.05);the comparison of area ratio of condyle-fossa in the sagittal section shows:the data of the affected side was significantly lower than the normal side(p<0.05).(2)In the comparison of the normal TMJs and affected TMJs,the condyle area in the sagittal section of the affected TMJs was significantly smaller than that of the normal TMJs(p<0.05);there was no siginificant difference between the glenoid fossa area in the sagittal section of the affected TMJs and that of the normal TMJs;their condyle-fossa ratio was as follows,the data of the affected TMJs was significantly lower than that of the normal TMJs(p<0.05).(3)There was a significant association between the area of mandible condyle,the condyle-fossa area ratio in the sagittal section and anterior disc displacement of TMJ.(4)The condyle area and condyle-fossa area ratio in the sagittal section were significantly lower of the normal side of TMJ of ADD patients than that of normal cases.Conclusion(1)The value of sagittal section area of condyle and the area ratio of condyle with fossa were factors that strongly related to the occur of TMJ anterior disc displacement;(2)The condyle was more likely to reconstruct with an anterior disc displacement,and the size of the condyle tended to absorb and ended at a smaller size.(3)Left and right TMJ were symmetric with each other in healthy individual;(4)The condyle size was not related with the size of its glenoid fossa.(5)No difference was found for size of condyle and glenoid fossa between different gender.