Correlation of immunohistochemical characteristics of the craniomandibular joint with the degree of mandibular lengthening in rabbits.
OBJECTIVE
This study examined immunohistochemical changes in the craniomandibular joints of rabbits after distraction osteogenesis following mandibular corticotomy.


METHODS
The experimental animals (n = 8) were divided into 3 groups that underwent 2, 3.5, and 5 mm of unilateral distraction osteogenesis (groups 1, 2, and 3, respectively). After corticotomy of the left mandibular body and a 7-day healing period, a second operation was performed to expose the device. Distraction was then performed at the rate of 0.5 mm/d. A 14-day consolidation period was allowed after the distraction was complete. Changes in cartilage, osteoblast activity, and osteoclast activity were then examined.


RESULTS
The differentiation and proliferation of cartilage increased in groups 1 and 2, were highest in group 2, and decreased in group 3. Group 2 also showed the greatest increase in the width of the hypertrophic chondrocyte layer. Relative to the control group, osteoclast activity was only somewhat higher in groups 1 and 2 but was significantly higher in group 3. Osteoblast activity was significantly higher in groups 1 and 2 than in the control group. However, the osteoblast activity in group 3 was slightly lower than that in group 2. At the time of unilateral mandibular distraction, no degenerative changes of the temporomandibular joint were observed in groups 1 or 2, but bone resorption was observed in group 3.


CONCLUSIONS
The unilateral mandibular distraction of 2 or 3.5 mm was acceptable in that no degenerative changes of the temporomandibular joint were observed on either the distraction or the nondistraction sides. Five millimeters of distraction might be beyond physiologic limits.
Department of Oral and Maxillofacial Surgery, Oral Biology Research Institute, College of Dentistry, Chosun University, Gwangju, South Korea. SGCKIM@mail.chosun.ac.kr
Su-Gwan
SG
Kim
Ju-Cheol
JC
Park
Dong-Wan
DW
Kang
Byung-Ock
BO
Kim
Jung-Hoon
JH
Yoon
Se-Inn
SI
Cho
Han-Cheol
HC
Choe
Chun-Sik
CS
Bae
D000469:Alkaline Phosphatase / Q000032:analysis / Q000378:metabolism; D000818:Animals; D016723:Bone Remodeling; D001862:Bone Resorption / Q000209:etiology / Q000473:pathology; D001973:Bromodeoxyuridine / Q000032:analysis / Q000378:metabolism; D002402:Cathepsin D / Q000032:analysis / Q000378:metabolism; D020219:Chondrogenesis; D007124:Immunoenzyme Techniques; D008297:Male; D008334:Mandible / Q000378:metabolism / Q000601:surgery*; D008335:Mandibular Condyle / Q000378:metabolism; D019647:Oral Surgical Procedures / Q000009:adverse effects; D010006:Osteoblasts / Q000378:metabolism; D010010:Osteoclasts / Q000378:metabolism; D019857:Osteogenesis, Distraction / Q000009:adverse effects; D011817:Rabbits; D013373:Substance P / Q000032:analysis / Q000378:metabolism; D013704:Temporomandibular Joint / Q000378:metabolism*; D019063:Tenascin / Q000032:analysis / Q000378:metabolism
D019063:Tenascin; D013373:Substance P; D000469:Alkaline Phosphatase; D002402:Cathepsin D; D001973:Bromodeoxyuridine