Cephalometric changes after gradual lengthening of the mandible: an experimental study in sheep.

Gradual distraction after osteotomy has been used both clinically and experimentally to lengthen the mandible. In this experimental study in sheep, the changes in dimensions after osteotomy and gradual distraction were analysed by means of cephalometry. There was a strong correlation between the amount and duration of distraction and the increase in length of the mandible. The difference in length between the operated and control sides persisted for up to 1 year. It was concluded that new bone was deposited and that the increase in length of the mandible was real and permanent.