MICROSCOPIC AND MOLECULAR EVALUATION OF A NEW PULP PROTECTIVE BIOMATERIAL IN TEETH UNDERGOING PULPOTOMY IN RATS

• Grant number: 24/09074-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2024
• End date: September 30, 2028
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Léa Assed Bezerra da Silva
• Grantee: Ana Paula Gomes e Moura
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Therapeutic strategies that preserve the dental pulp are the best choices in the treatment of vital teeth with deep carious lesions or pulp exposures, known as vital pulp therapy (TPV). The materials used in TVD must maintain pulp vitality and promote the differentiation of pulp stem cells into odontoblastic cells, favoring the formation of reparative dentin or mineralized tissue. Thus, the objective of this study will be the microscopic and molecular evaluation of the use of a biomaterial composed of a Gelfoam® membrane embedded in the CAP-p5 peptide, as a pulp protective material during pulpotomy, in rat molars. Ninety-six animals will be divided into four groups (24 animals/group), as follows: Group I: pulp exposure covered by gutta-percha; Group II: pulp exposure and calcium hydroxide P.A. paste on the pulp + calcium hydroxide cement; Group III: pulp exposure and Gelfoam® membrane on the pulp; and Group IV: pulp exposure and Gelfoam® membrane associated with the CAP-p5 peptide on the pulp. All groups will have three subgroups (8 animals each), differentiating into subgroups A: period of 7 days; subgroups B: 30-day period; subgroups C: period of 60 days. The teeth of all animals will be sealed with self-curing restorative glass ionomer. After periods of 7, 30 and 60 days, the animals will be euthanized and the maxillae and mandibles will be processed for microscopic and molecular analysis. The slides will be stained in hematoxylin and eosin (HE) and analyzed under optical microscopy for descriptive analysis of the characteristics of the pulp chamber and possible formation of a dentin bridge, in addition to the root pulp tissue and apical and periapical regions. Furthermore, descriptive and quantitative analysis of the possible dentin bridge formed with the microscope in fluorescent mode. Histomicrobiological evaluation for the presence and location of bacteria and bacterial concentration/intensity, using modified Brown and Brenn staining. To analyze the presence of calcium, Von Kossa staining will be performed. An immunofluorescence assay will also be performed for the markers CD73, CD90 and CD105, to detect mesenchymal stem cells in the pulp tissue. RT-qPCR analysis will be performed for the markers dentin matrix protein 1 (DMP-1) and dentin sialophosphoprotein (DSPP). The results obtained will be subjected to statistical analysis using appropriate tests according to the nature of the data. For all analyzes a significance level of 5% will be adopted.