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Efficacy of experimental chitosan solution with natural extracts in permeability and dentinal tubule occlusion

Grant number: 16/12786-7
Support type:Scholarships in Brazil - Master
Effective date (Start): December 01, 2016
Effective date (End): February 28, 2018
Field of knowledge:Health Sciences - Dentistry
Principal Investigator:Regina Guenka Palma-Dibb
Grantee:Tatiana Carvalho Montes
Home Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Frequent oral cavity exposure to endogenous and exogenous acids favors erosives processes. With the decay of pH, followed by neutralization, demineralization tissue starts, promoting the activation of metalloproteinases, which not inhibited, contribute to its progression, caused mainly by erosion, furthermore, the contact with acid exposes dentin and dentinal tubules, which may cause the development of dentine hypersensitivity. In order to inhibit erosion process, natural inhibitors of MMPs have been employed, such as green tea extracts (EGCG) and gardenia fruit (genipin), which by reacting with amine groups within and between molecules collagen, form intra and intermolecular crosslinks. The aim of this in vitro study will be evaluate the effect of an experimental solution containing chitosan and natural extracts of green tea (EGCG) and gardenia jasminoides (genipin) in dentin permeability and dentinal tubule occlusion. The specimens will be made from the bovine incisors root dentin. Will be 45 dentine discs, with 4 mm diameter and thickness equal to the distance between the dentine surface and the wall of the root canal. With an intention to obliterate dentinal tubules, a solution containing Chitosan, sodium tripolifostato (TPP), EGCG and genipin as main components, will be developed. The specimens will be divided into 3 groups, two experimental treatment groups (experimental solution; desensitizing NanoP) and a control group (artificial saliva) .The dentin permeability will be measured in five times (Pre-erosive challenge, in smear layer presence; after erosive challenge with citric acid; after 1st test products application; after erosive challenges, post test products application; after 2nd test products application) with confocal microscopy analysis after erosive challenge and after 1st test products application. In confocal microscopy analysis, the number of tubules, area and lumen perimeter are made of the difference of initially degraded dentin and dentin degraded with subsequent surface treatment. The data obtained from permeability tests and number of tubules, area and lúmen perimeter (quantitative) will be analyzed regarding their distribution. Verification of normality and homogeneity of the sample distribution will be held. If it is normal and homogeneous will be performed analysis of variance, otherwise performed nonparametric test. The morphological analysis will be assessed qualitatively. (AU)