Results of crown-height reduction and partial coronal pulpectomy in rhesus monkeys (Macaca mulatta)

Background and Purpose: In research facilities using non-human primates, crown-height reduction with partial coronal pulpectomy ("vital pulpotomy") is routinely performed on canine teeth of adult male monkeys to reduce self-trauma and the potential for injury to staff or cage-mates. Success of pulpotomy techniques in humans is reportedly 40 to 60%. Failure leads to chronic inflammation and pulp necrosis, which introduces variability in research animals, and may affect research results. The purpose of the study reported here was to determine failure rate of this procedure by evaluating clinical and radiographic findings at 3, 9, and 24 months after crown amputation and partial coronal pulpectomy of maxillary canines in adult male rhesus monkeys. Methods: Forty-seven maxillary canine teeth from 24 adult male rhesus monkeys were treated by use of crown amputation and partial coronal pulpectomy, using standard dental technique. Follow-up clinical and radiographic examination was performed 3, 9, and 24 months after surgery. Results: At three months after surgery, there was no clinical evidence of failure at any of the teeth. On the basis of radiographic findings, 2 of 47 teeth had failed and one was suspicious for early failure. At nine months, clinical evidence of failure was not apparent; radiographically, 5 of 44 teeth appeared to have failed and 3 others were suspect. Two years after surgery, failure of 41 teeth was clinically evident in two animals, with radiographic evidence of failure in five, and suspicion of early failure in an additional six. Conclusions: The failure rate of crown amputation and partial coronal pulpectomy of canine teeth in adult male rhesus monkeys is high, and the chronic inflammation associated with this is cause for concern.