[Enamel surface roughness after interproximal enamel reduction with different methods in vitro]

To assess the surface roughness after application of interproximal enamel reduction(IER) with different methods under a pH cycling experiment in vitro.

Thirty healthy premolars were used after removal for orthodontic reasons and divided into three groups. One proximal surface underwent IER as the experimental surface while the other was untreated as control. Each group underwent IER according to one of the following techniques: tungsten carbide bur and Sof-Lex disks (group 1); tungsten carbide bur and 10% maleic acid on Sof-Lex disk (group 2); tungsten carbide bur, Sof-Lex disks and fluor protector (group 3). All samples were treated using the pH cycling experiment everyday for 60 days. Enamel surface roughness value (Ra) was measured with profilemetry and morphology was observed under scanning electron microscopy (SEM). Statistical analysis was performed using SPSS 13.0 software package by means of paired t test or one way ANOVA.

Ra of the experimental surface increased significantly than that of control in each group (P < 0.01). There was no significant difference among the experimental surfaces among the three groups (P > 0.05). SEM images demonstrated that enamel surfaces were smoother in the group 2 and group 3 compared with the experimental surfaces in group 1.

IER significantly increases surface roughness of the proximal enamel. The application of topical fluride on the enamel surface seems to be advantageous.