[A comparative study of two imaging techniques for the diagnosis of sagittal fracture of mandible condyle].

OBJECTIVE

To investigate the relationship between fractured fragment and joint disc displacement after sagittal fracture of mandibular condyle (SFMC).

METHODS

based on CT examination, SFMC were classified into fissue, displacement and dislocation type. Based on oblique sagittal MRI examination, the displacement of joint disc was grouped into type A and type B. Abnormal superiorposterior attachment was classified into elongation and avulsion type.

RESULTS

CT exmination were taken in 26 patients with 41 SFMC. There were 5 SFMC (12%) with fissue type, 18 SFMC (44%) with displacement type and 18 SFMC (44%) with dislocation type. Both CT and MRI examination were taken in 19 patients with 32 SFMC. There were 27 (84%) SFMC with disc displacement. Five SFMC with type fissue showed no signs of disc displacement. Among 15 SFMC with type displacement, there were 3 cases with type A disc displacement and 12 cases with type B disc displacement. All the dislocated SFMC (12 cases) were type B disc displacement. In term of superiorposterior attachment figures, 4 cases (4/5) of type fissue SFMC showed normal. 14 cases (14/15) of the displacement SFMC showed elongated and all cases with dislocated SFMC showed sign of avulsion. There were 20 cases (63%) showing superior joint effusion. There were 13 cases (13/15) with displaced SFMC and 6 cases with dislocated SFMC showing joint effusion. One case with fissue SFMC showed no sign of joint effusion.

CONCLUSIONS

Joint effusion, disc displacement and abnormal superiorposterior attachment were related to the displacement of condyle which was involved with SFMC.