Effect of demineralizing agents on roots surfaces: microscopic study in rats subcutaneous tissue.

• Grant number: 09/16853-7
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): June 01, 2010
• Effective date (End): December 31, 2010
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal researcher: Maria Lúcia Rubo de Rezende
• Grantee: Gabriela Mariela Schiavetto
• Home Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Radicular biomodification using physical and chemical agents have been widely approached and stressed as important co-operating procedure aiming at periodntal tissue reattachment to dental roots previously exposed to periodontal disease. Demineralization by citric acid, phosphoric acid, tetracycline or EDTA is one of the most used biomodifyers for this purpose in different protocols relative to its concentration, lasting time and way of application. Nevertheless, although several of those substances have demonstrated to be effective on neutralizing bacterial endotoxin, widening of dentinal tubules and smear layer removal, there is still controversy in respect to the necessity of their use for fiber reattachment ad cellular adhesion on diseased roots surfaces. With the aim of contributing with the understanding and validation of biomodification procedures, this study will evaluate the ability of collagen fibers attachment and inflammatory response of rats' subcutaneous tissue to human radicular fragments previously exposed to periodontal disease, in which manual scaling and demineralization were performed during 3 minutes by the following chemical agents: citric acid pH 1, acid tetracycline, phosphoric acid at 37% and EDTA at 24%. Saline solution will serve as positive control and non contaminated fragments will serve as negative control. The radicular fragments will be implanted subcutaneously in 45 rats: 15 fragments for each type of treatment and 2 for animal. Biopsies containing the fragments and surrounding tissues will be obtained at 7, 14 and 30 days post-operatively, totalizing biopsies for type of treatment in each period. The specimens will histologically processed for light microscopy and stained with hematoxilin-eosin staining. In the sections, classic parameters for inflammation will be qualitatively evaluated and computerized quantitative analysis will be made for intensity of collagen fiber insertion to roots surfaces. The results will be compared among the groups using variance analysis (ANOVA) and Tukey test when statistically significant differences are found