Abstract
The aim of this study was to estimate the relationship of the presence of the bilaminar zone and temporomandibular joint (TMJ) structures on the MR images in juveniles using multivariate analysis. Four hundred eighteen TMJ MR imaging films taken from 209 juvenile subjects (71 male and 138 female, with ages ranging from 6 to 16) were used in this study. We appraised the presence of bilaminar zone, joint effusion, disk displacement, disk configuration, disk reduction of the maximum opening position, lateral disk displacement, condylar bony deformation and articular eminence configuration on the MR imaging.
The results in dicated that the upper stratum of the bilaminar zone could be identified in all of the 418 TMJs (100%), while the lower stratum of the bilaminar zone was identified in 107 TMJs (25.6%). Among 82 (75.9%) subjects, the lower stratum of the bilaminar zone was identified bilaterally, while it was unilaterally identified in 25 (23.4%) subjects. Based on score by category, it was found that the lower stratum of the bilaminar zone tended not to be identified in joint eminence configuration, moderate and severe anterior disc displacement, interior anterior disc displacement, disk displacement without reduction and condylar bony deformation on the MR image. In addition, the determining variable of scores according to showed that disk configuration, joint eminence configuration, joint with anterior disk displacement, disk displacement with or without reduction were some of the etiological factors for the lower stratum of the bilaminar zone.
In conclusion, our study implied that the presence of the lower stratum of the bilaminar zone on the MR imaging was one of the indication of the etiological factors of the TMJ internal derangement in juvenile subjects.
