| Objective: In this study, we obtained three dimensional reconstructed images of temporomandibular joint(TMJ) of patients with bruxism and unilateral mastication,and asymptomatic volunteers by cone beam CT(cone beam-computed tomography),measured temporalmandibular joint parameters of patients with bruxism and unilateral mastication by CBCT third-party software( Invivo5).The purpose of this study is to explore the effect of bruxism and unilateral mastication on temporomandibular joint morphology,and provide image basis for clinical diagnosis and treatment.Method: 30 cases, with the chief complaint of bruxism and unilateral masticatory symptoms,were selected as experimental group, and they are all from the clinic of Tianjin Medical University Dental Hospital during from October 2013 to June 2015. And we selected 30 healthy adults without bruxism and unilateral masticatory symptoms and history of temporomandibular disorder as the control group. They were all scanned by CBCT. At the same time,we obtained the three-dimensional reconstructed scanned images by Invivo5. Measured(1)Horizon-tal section:(1)Radius value(1)Antero-posterior diameter(3)Medial-lateral diameter(4)Axial angel;(2)Sagittal section:(1)Acetabulum depth(1)Aricular eminence inclination(3)Anterior space、superior space、posterior space(4)Condylar width;(3)Coronal section:(1)Force angle(1)Vertical angle, on the choosed final reference plane.All measurements were performed in the same condition for three measurements(measured by the experimenter). All data were analyzed by SPSS17.0 statistics software, expressed by ± s, and the test level of α=0.05. The two sides of the same sample were analyzed by paired t test, and the left and right sides of different samples were analyzed by independent samples t test, and p<0.05 indicated statistic significance.Results: A total of 90 cases of temporomandibular joint CBCT images were collected, including 30 cases in the control group, 30 cases in the bruxism group, and 30 cases in the unilateral mastication group. 1、There were no statistically significant differences in the bilateral TMJ measurements in the control group(p>0.05). 2、There were no statistically significant differences in the bilateral TMJ measurements in the bruxism group(p>0.05). 3、In the unilateral mastication group, there were statistically significant differences in the bilateral TMJ measurements in the superior space, as well as the condylar width(p<0.05), however, the differences in the rest of the measurements of the bilateral TMJ have no statistic significance(p>0.05). 4、Compared to the control group,the bruxism group had smaller Anteroposterior diameter、Medial-lateral diameter and Condylar width(p<0.05), and gre ater Acetabulum depth、Anterior space and Force angle(p<0.05). However, there were no statistically significant differences in the rest of the bilateral TMJ measurements(p>0.05). 5、The habitual side TMJ of unilateral mastication group showed smaller Antero-posterior diameter、Medial-lateral diameter、Superior space and Condylar width than the bilateral TMJ of control group(p<0.05), as well as greater Force angle(p<0.05)., however, the rest of the measurement value had no statistically significant differences(p>0.05).Conclusion: 1、In the control group, the size, morphology and the position of the bilateral mandibular condyle were basically symmetrical. 2、In the bruxism group, the structure of the bilateral TMJ was basically symmetrical, and there was no significant change in the position of the mandibular condyle,.What’s more, there maybe absorptive reconstruction in the ante-rior incline and neck of the condyle, and the condyle tends to become smaller. 3、In the unilateral mastication group, compared to the habitual side,the mandibular condyle of the unaccustomed side became polished and shorter, however,the condyle of the habitual side became smaller than that of the contol group, what’more, the position of condyle Shifted upwards. 4、The mandibular condyle would become polished and shorter while the TMJ suffering from the abnormal load. |
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