Molecular identification of bacteria from osteomyelitis of the jaws

The purpose of this study was to isolate and identify the bacteria in osteomyelitis lesion of 3 patients. Two lesions were due to the postinfection after extraction. The other was resulted from mal-fixation of both sides of mandibular angles. Pus samples were collected by needle aspiration from the lesion and examined by culture method. Bacterial culture was performed in three culture systems (anaer-obic, CO2, and aerobic incubator). Identification of the bacteria was performed by 16S rRNA gene cloning and nucleotide sequencing method. Our results showed that Streptococci species was predominantly isolated in both lesions of extraction socket. Only one species (Proteus vulagris) was detected in lesion of mandibular angle. This study was not sufficient to identify the causative bacteria in those osteomyelitis. However, our data may be offered the clue to solve the problem.

Histopathologic changes of the craniomandibular joint according to the amount of distraction after 6 weeks of distraction osteogenesis in rabbits

The purpose of this study is to observe histopathologic changes in the bilateral craniomandibular joints after allowing 6 weeks of consolidation by varying the amount of distraction in rabbit mandible. Eight rabbits weighing about 2 to 3kg were used. After corticotomy was performed on the left mandibular body between the first premolar and the second premolar region, a unilateral fixation device was placed. Then, a 7-day period was allowed without distraction of the device. The mandible was lengthened 0.5mm/day. Corticotomy and lengthening of mandible were not performed in control group. After the completion of the lengthening process, a 6-week-consolidation period was allowed. Then, the rabbits were sacrificed, and histologic examination of the craniomandibular joints was performed. Proliferative changes were observed in the craniomandibular joints in all groups. With the increasing amount of distraction, hypertrophy of the cartilage layer became more severe, bone formed was dense and enchondral ossification was clearly shown in subchondral bone. Hypertrophy of the cartilage layer was also seen in the non-distracted side as the distracted side in the experimental group. These results indicate that when physical force is applied constantly to joints, the proliferation of articular cartilage and bone formation are present. When more than 6 weeks of consolidation period is allowed at the time of performing distraction for more than 5mm, articular changes, especially, in the contralateral side should also be noted.