Pulp remains viable following vital amputation of the mesio-buccal root of the maxillary fourth premolar in dogs.

Vital amputation of the mesio-buccal root of the maxillary fourth premolar (P4) was performed bilaterally in 8 dogs. Histopathologic evaluation of the tooth structure revealed normal pulp in the remaining mesio-buccal, mesio-palatal, and distal roots and crown during a mean follow-up period of 3.5 +/- 1.9 months. Amputation site healing was characterized by a reparative dentin bridge produced by odontoid cells. Tunnel defects were observed in 13 of 16 (81%) dentin bridges. It is concluded that the pulp of a tri-rooted, periodontal disease-free tooth remains viable during a 6-month period following vital root amputation. These results point to the intriguing possibility that this may also occur in humans, however, this needs to be directly tested in man.