[Mandibular condensability and length contraction: an animal experimental study].
OBJECTIVE
To investigate the condensability of mandibular length.


METHODS
In six goats were used in the study. Corticotomy at right mandibular angles was performed via extral-oral accession. Special devices were applied to shorten the mandible by 0.5 mm per three days respectively.


RESULTS
1. Mandibular angles of the six goats were shorten by 0.8 cm to 1.3 cm respectively in 48 days to 78 days; 2. In spite of the lower ascending ramus moving forward and angles being blunt, the occlusion scarcely varied because of contralateral bite-lock; 3. X-ray demonstrated that, at first, bone density in contracted areas declined, and then increased gradually to almost normal density; 4. Under microscope there were three tissues layers from central to lateral within the bone gap: fiber layer, cartilage layer and bone layer, and fiber layer gradually transform into cartilage layer with the fixed time. At the end of fixation they all transform into bone tissue.


CONCLUSIONS
Contraction osteogenesis is actually a process of compression, absorption and rebuilding. It is feasible that using contraction osteogenesis to shorten the mandible via cortcotomy.
Li
Yong
Y
Dept. of Oral and Maxillofacial Surgery, Hospital of Stomatology, Changqing Medical University, Chongqing 400015, China.
Tian
Wei-dong
WD
Zhang
Zhi-jie
ZJ
Deng
Feng
F
Zhong
Da-wen
DW
Wang
Zhi-bing
ZB
Dai
Hong-wei
HW
He
Mei
M
D000818:Animals; D016267:External Fixators; D005260:Female; D006041:Goats; D008297:Male; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D019647:Oral Surgical Procedures / Q000379:methods*; D010027:Osteotomy; D010521:Periosteum / Q000601:surgery; D011312:Pressure