Evaluation of the reaction of subcutaneous tissue of rats to implantation of white MTA and white Portland cement with radiopacifiers

O MTA por apresentar boas propriedades físico-químicas e biológicas é indicado como material retrobturador. O objetivo deste trabalho foi avaliar, microscopicamente, a resposta do tecido subcutâneo de ratos frente à implantação de tubos de polietileno contendo novas formulações desse material: ProRoot MTA®, MTA Branco® contendo dois tipos de radiopacificadores e cimento Portland branco com óxido de bismuto. Foram utilizados 36 ratos (Rattus norvegicus), divididos em 12 animais para cada período experimental. Cada animal recebeu quatro implantes de tubos de polietileno, preenchidos com os materiais recém-espatulados de um lado, e do outro guta-percha (controle). Após 15, 30 e 60 dias os animais foram mortos e os espécimes foram preparados para análise microscópica. Os resultados mostraram inflamação crônica granulomatosa induzida pelos materiais, com intensidade moderada a discreta, e organização e espessamento de uma cápsula fibrosa com o passar do tempo. Os cimentos induziram respostas teciduais semelhantes, mesmo com radiopacificadores diferentes na composição.Because of its good physicochemical and biological properties, MTA is indicated as a material for retrograde obturations. The aim of this study was to microscopically evaluate the response of the subcutaneous tissue of rats to the implantation of polyethylene tubes containing new formulations of this material: ProRoot MTA®, White MTA® containing two types of radiopacifiers, and white Portland cement with bismuth oxide. Thirtysix rats (Rattus norvegicus) were employed, which were divided into 12 animals for each study period. Each animal received 4 implants of polyethylene tubes filled with the recently prepared materials at one side, and gutta-percha at the other side (control). After 15, 30 and 60 days, the animals were killed and the specimens were prepared for microscopic analysis. The results demonstrated granulomatous chronic inflammation induced by the materials, of moderate to mild intensity, and organization and thickening of a fibrous capsule with time. The cements induced similar tissue responses, despite the presence of different radiopacifiers in their composition