Pulpal and periapical response of dogs' teeth after pulpotomy and use of recombinant human bone morphogenetic protein-7 as a capping agent.

Objective: The purpose of this study was to evaluate the pulpal and periapical response of dogs' teeth after pulpotomy and the use of recombinant human bone morphogenetic protein-7 as a capping agent.

Methods: Pulpotomy was performed in 60 teeth from 6 dogs, and the remaining pulp tissue was capped with the following materials: (a) groups 1 and 5: recombinant human bone morphogenetic protein-7 associated with recombinant human-like collagen; (b) groups 2 and 6: recombinant human-like collagen; (c) groups 3 and 7: calcium hydroxide; and (d) groups 4 and 8: zinc oxide and eugenol cement. After 7 days (groups 1-4) and 70 days (groups 5-8), the animals were sacrificed and the pieces containing the teeth were removed and processed for histological analysis.

Results: Seven-day period: according to the type of inflammatory infiltrate observed in the root pulp tissue: (a) groups 1 and 2 were classified as severe with intense vascular proliferation; (b) group 4 was classified as moderate; and (c) group 3 was classified as mild. No dentin bridge formation was observed in any specimen, and the periapical region had normal appearance. 70-day period: groups 5, 6, and 8 showed no dentin bridge formation, and the remaining pulp tissue presented necrotic areas with inflammatory cells in the periapical region as well as bone and cemental resorption. In group 7, there was dentin bridge formation, absence of inflammation, and absence of mineralized tissue resorption.

Conclusion: The use of rHuBMP-7/rHuCollagen as a capping material after pulpotomy did not show either satisfactory apical and periapical response or capacity of inducing deposition of mineralized tissue.