[Mode of new bone formation following distraction osteogenesis in mandibular lengthening].

OBJECTIVE

To investigate the mode and influential factor of new bone formation following distraction osteogenesis in mandibular lengthening.

METHODS

Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custom-made distractor was used to lengthen the mandible at a rate of 1 mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectively at 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology.

RESULTS

Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that distractor loosed.

CONCLUSION

The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.