Pulpal and periapical response of dogs’ teeth after pulpotomy and use of bone morphogenetic protein (rHuBMP-7). Histopathologic and radiographic study.

Author(s)

Francisco Wanderley Garcia de Paula e Silva

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2006-02-06

Examining board members

Lea Assed Bezerra da Silva; Alberto Consolaro; Mario Roberto Leonardo

• Advisor: Lea Assed Bezerra da Silva

Abstract

The purpose of this study was to evaluate, both histopathologically and radiographically, the pulpal and periapical response of dogs’ teeth after pulpotomy and use of recombinant human bone morphogenetic protein-7 (rHuBMP-7). For such purpose, 60 teeth (120 roots), obtained from 6 dogs, were divided in 8 groups and evaluated in two experimental periods: 7 days (Groups I, II, III, IV) and 70 days (Groups V, VI, VII, VIII). After pulpotomy, pulp remnant was covered with the following materials: Groups I and V - recombinant human bone morphogenetic protein-7 (rHuBMP-7) associated to recombinant human like collagen (rHuCollagen); Groups II and VI - recombinant human like collagen (rHuCollagen); Groups III and VII (negative control) – calcium hydroxide and sodium chloride solution; and Groups IV and VIII (positive control) – zinc oxide and eugenol. At the established experimental periods, the animals were sacrificed and the anatomic pieces were obtained and histologically processed. The histopathologic evaluation was realized subjectively in a light microscope. The radiographic evaluation was performed considering the integrity of the lamina dura, presence of areas of periapical bone rarefaction, root resorption (internal and external) and dentin bridge formation. The results were analyzed statistically using Fisher\'s exact test. In the specimens presenting periapical bone rarefaction areas, the lesions’ radiographic measurements were compared among the groups using the Kruskall-Wallis test. The histopathologic findings in the 7-day period revealed that Groups I and II presented a severe inflammatory infiltrate and intense vascular proliferation in the pulp tissue, Group IV presented a moderate inflammatory infiltrate while Group III presented a mild inflammatory infiltrate and intact pulp tissue. In all groups, there was no dentin bridge formation and the periapical region had normal appearance. In the 70-day period, Groups V, VI and VIII showed no dentin bridge formation and pulp tissue presented necrotic areas with inflammatory cells in the periapical region as well as bone and cemental resorption. On the other hand, in Group VII, there was dentin bridge formation, absence of inflammatory process and absence of resorption of mineralized tissues. Regarding the radiographic findings, in the 7-day period, all specimens in Groups I, II, III and IV present intact lamina dura, absence of periapical bone rarefaction, absence of root resorption (internal and external) and absence of dentin bridge formation. In the 70-day period, Groups V, VI and VIII did not present dentin bridge formation in any specimen. Periapical bone rarefaction areas were observed in 100% of the roots in Group VI, 60% of the roots in Group VIII and 40% of the roots in Group V. The largest lesions were found in Group VI, followed by Groups V and VIII (p<0.05). In Group VII, there was dentin bridge formation in 60% of the cases, intact lamina dura and absence of periapical bone rarefaction in 100% of the cases. Based on these results, it may be concluded that recombinant human bone morphogenetic protein-7 associated to recombinant human like collagen did not present satisfactory results. (AU)