Effects of irrigation solutions on dentin wettability and roughness

Irrigation solutions are used to disinfect the root canal, flush out debris, and dissolve pulp tissue. It is hypothesized that irrigation solutions might influence the physicochemical properties of human root canal dentin including the wettability and roughness.

The roots of 20 human permanent anterior teeth were sectioned longitudinally into dentin slices and randomly divided into 4 groups with different treatments as follows: (1) 17% ethylenediaminetetraacetic acid (EDTA) for 10 minutes, (2) 5.25% NaOCl for 10 minutes, (3) 3% H2O2 for 10 minutes, and (4) distilled water as control. Wettability was evaluated by contact angle measurement. Atomic force microscopy was used to measure the surface roughness (Ra).

Water contact angles significantly decreased from 54.35 degrees (control) to 22.04 and 46.35 degrees on the dentin treated by 5.25% NaOCl and 3% H2O2, respectively, with the wettability increasing accordingly (both P < .05). The roughness of dentin surfaces (Ra) was increased from 85.39 (control) to 121.90 and 140.49 nm by 5.25% NaOCl and 17% EDTA, respectively (both P < .05).

These findings indicated that all the irrigation solutions could alter the physicochemical characteristics of dentin surfaces and might influence bacterial adhesion.