Birefringence Alterations of Dentin Collagen Treated with Endodontic Irrigant Solutions

Birefringence consists in anisotropic propertie caused by the difference in the refractive index of an object. One of the applications of the birefringence research is solving problems of organization and physiology of the collagen fibers. Alterations on collagen structure can induce interferences in adhesion between dentin and restorative materials. Objectives: This study evaluated the alterations on the collagen birefringence after treatment with different endodontic irrigant solutions. Methods: 60 bovine incisors were divided in 6 groups: Group I – 5,25% NaOCl + 17% EDTA, group II – 2% Chlorhexidine Gel, group III – 5,25% NaOCl, group IV – 17% EDTA, group V – 2% Chlorhexidine Gel + 17% EDTA, group VI – saline. The samples had their crowns cut, their dental pulps extirpated and were irrigated in accordance with the group they belonged, using a total volume of 10ml for each sample except for the 2% chlorhexidine gel groups, in which 2ml of total volume for each sample was used. After the instrumentation, the irrigant solutions were maintained for 45 minutes in the root canal, except for 17% EDTA groups which were maintained for 15 minutes. The samples were evaluated through the polarized light microscopy. Results: The results demonstrated birefringence alterations on the groups I and III. Conclusions: According this, it can be observed the occurence of possible variations in the structure of the collagen organization.