original article Dental Press Endod. 2015 May-Aug;5(2):26-32 © 2015 Dental Press Endodontics 26 Evaluation of rat tissue response to Guedes-Pinto and calcium hydroxide pastes by morphological analysis of repair in rat’s tooth socket ABSTRACT In order to evaluate late biological response of two types of filling material of deciduous teeth, calcium hydroxide and Guedes-Pinto pastes, the implantation technique in rat sockets was employed. For morphological analysis, carried out after 7 and 28 days, 48 rats had their maxil- lary right central incisor removed, and a polyethylene tube implant containing one of the pastes was placed into the socket. On the 7 th day, calcium hydroxide paste caused greater edema than Guedes-Pinto paste, and both types of material showed connective tissue with fibroblasts and blood vessels, with macrophages and lymphocytes. On the 28 th day, calcium hydroxide paste had connective tissue with a large amount of macro- phages and lymphocytes near the material, whereas in further areas, it had neofomed trabeculae. For the Guedes-Pinto paste, there were neoformed bone tra- beculae nearby. The latter were found in larger amounts in areas further from the material surface. Guedes-Pinto paste caused less edema and provided less interference in the repair process. Keywords: Deciduous tooth. Calcium hydroxide. Root canal therapy. Root canal filling material. 1 PhD professor of Pediatric Dentistry, Universidade do Oeste Paulista (UNOESTE), School of Dentistry, Presidente Prudente, São Paulo, Brazil. 2 MSc in Animal Sciences, Universidade Estadual do Mato Grosso do Sul (UFMS), Aquidauana, Mato Grosso do Sul, Brazil. 3 Professor of Pediatric Dentistry, Universidade do Oeste Paulista (UNOESTE), School of Dentistry, Araçatuba, São Paulo, Brazil. 4 PhD professor of Endodontics, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), School of Dentistry, Araçatuba, São Paulo, Brazil. Contact address: Karine Takahashi Rua Francisco Scardazzi, 350, São Judas – CEP: 19.023-190 Presidente Prudente/SP, Brazil – E-mail: karine@unoeste.br Submitted: July 25, 2015. Revised and accepted: August 05, 2015. How to cite this article: Takahashi K, Maltempi Filho P, Cunha RF, Dezan Junior E. Evaluation of rat tissue response to Guedes-Pinto and calcium hydroxide pastes by morphological analysis of repair in rat’s tooth socket. Dental Press Endod. 2015 May- Aug;5(2):26-32. DOI: http://dx.doi.org/10.14436/2358-2545.5.2.026-032.oar » The authors report no commercial, proprietary or inancial interest in the prod- ucts or companies described in this article. Karine TAKAHASHI 1 Paulo MALTEMPI FILHO 2 Robson Frederico CUNHA 3 Eloi DEZAN JUNIOR 4 DOI: http://dx.doi.org/10.14436/2358-2545.5.2.026-032.oar