LAUSR

INTRODUCTION Although epigallocatechin-3-gallate (EGCG) from green tea has been sucessfully used in the prevention and treatment of several infectious and immunoinflammatory diseases due to its proven anti-inflammatory, anti-oxidant, antimicrobial and anti-resorptive role, its use as an intracanal dressing has not been proposed. The aim of this study was to develop a formulation based on Epigallocatechin-3-gallate (EGCG) for endodontic use by assessing its physicochemical and biological properties. METHODS Initially, physicochemical characterization of EGCG was performed by ultraviolet-visible (UV/Vis) and fluorescence spectroscopy to evaluate if the properties were maintained in acidic pH and time (1-6, 24 and 27 hours). After that, biological studies evaluated the developed formulation of EGCG at different concentrations (1,25; 5; 10 and 20 mg/mL). The tissue compatibility with subcutaneous tissue of mice was evaluated by plasma leakage after 24 hours and the examination of macroscopic and microscopic features at 7, 21 and 63 days after insertion of polyethylene tubes containing the formulations. The repair of experimentally induced periapical lesions in dog teeth by radiographic and histopathological analysis was also evaluated. The scores were statistically analyzed by the chi square and Fisher's exact test. The analysis of variance (ANOVA) followed by Tukey's post-test were used for the quantitative analysis. The significance level was 5%. RESULTS The physicochemical characterization performed under UV/Vis spectrophotometry showed that the EGCG properties remained unaltered in acid pH and in function of time, keeping it's wavelength to 274 nm. Macroscopic parameters evaluated at 7, 21 and 63 days showed that all concentrations presented no epithelial ulceration, presence of mild superficial tissue necrosis, edema and vascularization, with no significant difference in the control group. During all periods of microscopic examination, all groups presented the absence of abscess foci, edema and the presence fibrous capsule and neovascularization. The presence of reparative tissue with the gentle presence of neutrophilic inflammatory cells was also observed for all groups, except for calcium hydroxide paste group that presented a more pronounced inflammation and tissue necrosis, at days 7 and 21 (p<0.001). At day 63 all groups presented absence of inflammatory infiltrate and necrosis. The evaluation of dog teeth showed that treatment with the EGCG formulation provided a reduction of the periapical radiolucent area and allowed the repair of apical and periapical tissues (p>0.05). CONCLUSIONS The developed formulation based on EGCG from green tea presented physicochemical stability, tissue compatibility and provided the repair of periapical lesions when used as an intracanal dressing.