Effect of polyaspartic acid on dentin regeneration in rat molars

• Grant number: 20/10208-1
• Support type: Scholarships in Brazil - Master
• Effective date (Start): April 01, 2021
• Effective date (End): January 31, 2022
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal researcher: Roberto Ruggiero Braga
• Grantee: Fernanda Furuse Ventura dos Santos
• Home Institution: Faculdade de Odontologia (FO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 19/04737-4 - Dentin remineralization with the use of composite containing calcium orthophosphate particles associated with a Polymer-Induced Liquid Precursor (PILP): material development, in vitro and randomized clinical studies, AP.TEM

Abstract

Recently, it was demonstrated that a non-collagenous protein analog was able to guide the mineralization of a collagen scaffold and induce stem cell differentiation in osteoblasts, leading to the formation of a tissue similar to native bone (Thrivikraman et al., Nat Commun 2019). Thus, despite the good results achieved with calcium silicate (mineral trioxide aggregate, MTA) and Ca(OH)2 cements in pulp exposure cases, it is possible that biomimetic analogs stimulate dentin regeneration through greater differentiation of pulp stem cells into odontoblasts and guided mineralization of the dentin matrix, resulting in the formation of a reparative dentin with superior histological characteristics to that found with the use of Ca(OH)2 and MTA and in less time. The aim of this study is to verify whether the use of a biomimetic analog (polyaspartic acid, pAsp) associated with MTA would provide superior results to pulp capping with MTA only. Wistar rats (N=40) will be divided into two groups, according to the postoperative period (7 and 14 days). Under general anesthesia, mechanical pulp exposure of the occlusal surface of the first maxillary molars will be performed followed by one of the treatments (randomly defined, n=10): CIV Group (negative control) - only sealing the cavity with conventional glass ionomer cement (GIC); MTA Group (positive control) - pulp capping with MTA and cavity sealing with GIC; pAsp Group - application of 20 ¼L of pAsp solution and sealing the cavity with RMGIC; MTA / pAsp Group - application of pAsp mixed with MTA (before manipulation) in the ratio of 5:1 (by mass) and sealing the cavity with RMGIC. After euthanasia and processing of the hemimaxillas, the secctions will be submitted to histopathological analysis (HE staining) and immunohistochemical analysis to detect Dentin Sialoprotein (DSP), Nestin, Osteopontin (OPN) and Dentin Matrix Protein 1 (DMP1). Data analysis (qualitative or semi-quantitative) will be defined after preliminary studies. (AU)