OBJECTIVETo analysis the cause of malocclusion that was found in patients suffering from condylar neck and subcondylar fractures after perfectly anatomic reduction and rigid fixation.

METHODSThere were 23 cases of malocclusion in the patients of condylar neck and subcondylar fractures after anatomic reduction and rigid fixation during 1994 to 2001. The possible reasons were studied, and the treatment methods were proposed.

RESULTSBoth distortion and(or) fracture of miniplates and displacement anain of the condylar process after operation were not found in all 23 cases. There were 6 cases of open bite at the molar teeth of the fractured side, while the normal occlusions were showed in the nonfractured side. 11 cases showed that the whole mandibles were moved slightly to the nonfractured side. 4 cases showed that the mandible of fractured side moved slightly to the nonfractured side and the occlusion of nonfractured side were normal. 2 cases showed premature contact at the fractured molar teeth and the anterior teeth showed open bite. There were 5 cases of facial nerve damages, 2 cases wound infection, 2 cases TMJ chronic pain and 1 cases TMJ click and(or) murmur.

CONCLUSIONSAlthough the anatomical reduction and miniplate rigid fixation were operated on the condylar neck and subcondylar fractures, there were probably having the chance of showing malocclusion. The malocclusion was not caused by the fracture itself, but in the TMJ and/or muscular injury. Therefore, the malocclusion can be cured with intermaxillary elastic traction and functional exercise. Sometimes, the occlusal adjustment may be performed to resume the normal occlusion. In any case, operation is not needed.