Effect of deproteinization before and after acid etching on the surface roughness of immature permanent enamel

The purpose of this in vitro investigation was to assess the effect of deproteinization before and after acid etching on the surface roughness of immature human enamel of permanent teeth compared to acid etching alone using noncontact three-dimensional (3D) optical profilometer.

Forty-eight enamel blocks were randomly distributed into 4 groups (12 each) according to the surface treatment in the form of deproteinized with 2.5% sodium hypochlorite (NaOCl) before and after acid etching with 32% phosphoric acid (H3PO4) compared to application of H3PO4 alone. The surface roughness (Sa) was measured using a 3D optical noncontact surface profiler. Two specimens from each group were selected and prepared for scanning electron microscopic (SEM) analysis. Shapiro-Wilk test, one-way analysis of variance, and Tukey's honest significance difference test were used. All statistical analyses were established with a significance level of P < 0.05.

The highest surface roughness (Sa) was recorded for Group 3/NaOCl ± H3PO4 and the lowest Sa was recorded for Group 1 (control). All surface treatments applied showed significantly greater values of surface roughness (Sa) than the enamel surfaces with no surface treatment (control). There was significant difference between control group and Group 2/H3PO4 (P = 0.002), Group 3/NaOCl ± H3PO4 (P = 0.0001), and Group 4/H3PO4 ± NaOCl (P = 0.017). There was no significant difference between Group 2/H3PO4 and Group 4/H3PO4 ± NaOCl. SEM evaluation showed different topographical features of deproteinized enamel surface.

Deproteinizing the enamel of immature permanent teeth with 2.5% NaOCl before and after acid etching with 32% H3PO4 increased surface roughness compared to the application of H3PO4 alone.