Reinnervation of teeth after segmental osteotomy in the cat. The effect of segment repositioning and bone grafting.

The reinnervation of teeth after segmental osteotomy has been investigated using electrophysiological techniques in 6 cats. An osteotomy which divided the entire mandible was carried out bilaterally. The anterior segment was repositioned anteriorly by 5 mm and in 3 animals bone grafts were inserted at the osteotomy sites. A jaw opening reflex could be evoked by stimulation of 9 of the 12 denervated canine teeth by 9 weeks after the osteotomy. 12 weeks after the operation, recordings were made from the denervated teeth, the inferior alveolar nerve central to the osteotomy, and from nerves supplying adjacent tissues. The results were compared with those of previous experiments in which the anterior segment was not repositioned. Regenerating inferior alveolar nerve fibres re-innervated 18 of the 24 teeth denervated by osteotomy without bone grafting and 21 of the 24 teeth denervated by osteotomy with bone grafting. These fibres were few in number and had decreased conduction velocities. Pulpal fibres were also present in the ipsilateral mental and lingual nerves and the contralateral inferior alveolar, mental and lingual nerves. There was very little difference in the reinnervation of the teeth after osteotomy without repositioning the segment, after repositioning the segment without bone grafting or after repositioning with bone grafting.