Structural analysis of bovine root dentin after use of different endodontics auxiliary chemical substances

The use of chemical substances in endodontics during chemical-mechanical preparation may alter the structure of dentin, mainly collagen, which contributes considerably to the mechanical properties of this structure. This study evaluated the effect of different auxiliary chemical substances during endodontic treatment in root canal walls by implementing polarized light microscopy (PLM) and scanning electron microscopy (SEM).

Sixty bovine incisors were randomly divided into six groups (n = 10): G1, 5.25% NaOCl + 17% EDTA; G2, 2% chlorhexidine (CHX) gel; G3, 5.25% NaOCl; G4, 17% EDTA; G5, 2% CHX + 17% EDTA; and G6, 0.9% sodium chloride solution (control). Teeth were chemomechanically prepared and fractured into two fragments. One fragment was used for PLM, and the other was used for SEM analysis.

Groups treated with 5.25% NaOCl, whether associated or not associated to 17% EDTA, presented a significantly different birefringence pattern compared with the control group. The results revealed that groups irrigated with 2% CHX and EDTA, independently or combined, did not present any significant differences compared with the control group. SEM analysis showed structural alterations of the root canal inorganic matrix for all groups that used 17% EDTA.

It is possible to conclude that 5.25% NaOCl, whether associated or not associated with 17% EDTA, causes alterations in the dentin collagen. The obtained SEM images revealed demineralization areas for groups that used 17% EDTA alone or associated with other substances.