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[Investigation on radiographic signs of osteoarthrosis in temporomandibular joint with cone beam computed tomography in adolescents].

OBJECTIVE
To investigate the occurrence and radiographic signs of osteoarthrosis of the temporomandibular joints (TMJOA) with cone beam computed tomography (CBCT) in adolescents.


METHODS
Individuals with temporomandibular disorders (aged 10-19 years) in the patients group (n=386) and pre-orthodontic patients with malocclusion (aged 10-19 years) in the control group (n=339) were included in the present study. All the patients in both groups had been examined by CBCT. The abnormalities of the condyle were evaluated. The results of radiological findings were compared between the patients group and the controls by using chi-square tests. Inter- and intra-examiner agreements were assessed using Cohen's Kappa coefficient and all statistical analysis was performed using SPSS 13.0.


RESULTS
157 patients in the patients group and 41 subjects in the control group had radiographic signs of TMJOA. The occurrence of OA was significantly higher in the patients group (40.7%, 157/386) than in the controls (12.1%, 41/339), the difference was statistically significant (P<0.05). The occurrence of TMJOA was significantly higher in females (44.6%, 123/276) than in males (30.9%, 34/110) in the patients group (P<0.05) but showed no significant difference in the controls (females: 13.7%, 32/234, and male: 8.6%, 9/105, P>0.05). In addition, the patients group showed significantly higher occurrence of ill-defined cortical bone (31.7%, 65/205) small bony defect and extensive erosion (25.4%, 52/205) than the controls (1.7%, 1/58 and 5.2%, 3/58, respectively, P<0.05), while the subjects in the control group had significantly higher occurrence of flattening and shortening of the condyle (39.7%, 23/58) and sclerosis (39.7%, 23/58) than patients with temporomandibular disorders (6.3%,13/205 and 14.6%, 30/205, respectively, P<0.05).


CONCLUSION
TMJOA is not uncommon in adolescent patients with TMD and with malocclusion. Patients in the two study groups had different radiographic signs of OA. The patients with temporomandibular disorders often demonstrate erosive changes, while the pre-orthodontic patients with malocclusion often demonstrate relatively stable radiographic signs.