[The effect of dog bilateral distraction osteogensis in temporomandibular joint].
OBJECTIVE
To investigate the effect of bilateral mandibular distraction osteogenesis in the condyles.


METHODS
16 adult hybrid dogs were randomly divided into normal control group and experiment group. Experimental dogs underwent bilateral mandibular osteodistraction at a rate of 1 min/day. 4 dogs were killed respectively in distraction period, 2 and 8 weeks after completion of 10 days distraction. The bilateral condyles specimens were harvested and examined with histological and immunohistochemical methods.


RESULTS
Compared with normal control group, various degrees of irregularities and erosion were found in fibrocartilage of condyle in experiment group, including damage in fibrous layer, hyperplasia layer and proliferative layer and osteogenic activity in cartilage layer. A significant increase of TGF-beta1 expression was also found in experiment groups. TGF-beta1 positive staining was noted in hypertrophic cell, matrix and chondroblast, osteoblast and matrix in osteogenic activity areas. These changes were the most obvious in 2 weeks after completion of distraction.


CONCLUSIONS
Gradual bilateral mandibular distraction at a rate of 1 mm/day brought degenerative changes of condyle, but the changes are reversible.
Zhou
Nuo
N
Dept. of Oral and Maxillofacial Surgery, School of Stomtology, Guangxi Medical University, Nanning 530021, China.
Song
Shao-hua
SH
Mai
Hua-ming
HM
Liang
Fei-xin
FX
Wei
Shan-liang
SL
Yang
Yi-ping
YP
D000818:Animals; D004285:Dogs; D008334:Mandible; D010006:Osteoblasts; D019857:Osteogenesis, Distraction; D013704:Temporomandibular Joint; D053773:Transforming Growth Factor beta1
D053773:Transforming Growth Factor beta1