Tissue formation in the root canal following pulp removal

The purpose of this investigation was to elucidate the repair processes in the root canal after total removal of the pulp. In 47 teeth, 35 with vital pulp and 12 with necrotic pulp, the root canal was cleaned and reamed, whereupon a bleeding was induced and the canal partly filled. In some teeth there was no bleeding, and these comprised the control material, which was necessary in deciding whether a blood clot in the root canal was a condition for repair or would at least enhance the repair processes. The observation periods varied from 9 days to 3 years; at the end of the period, the tooth was extracted or the root resected with the apical periodontium. Histologic examination of the specimens revealed that in the teeth with vital pulp, fibrous connective tissue had formed in the root canal in 28 teeth. Concomitantly a deposition of cellular cementum had occurred in many cases. In the teeth with necrotic pulp, no repair occurred. The clinical implications of the experimental investigations are discussed.