Qualitative and quantitative evaluation of enamel after various post-stripping polishing methods: an in vitro study

The purpose of this study was to evaluate the ultramorphology and surface roughness of permanent tooth enamel after various post-stripping polishing methods.

Sixty extracted, permanent lower incisors were randomly assigned to two groups (Group A and Group B). Group A was morphologically assessed by a scanning electron microscopy (SEM) and Group B was assessed by a stylus profilometer which applied a surface roughness test. Each group was divided into five subgroups of six incisors. Four of the subgroups were subjected to interpoximal enamel reduction, followed by various polishing methods; the fifth subgroup served as a control. The polishing methods comprised; Subgroup 1, diamond disk followed by a fine Sof-lex disc; Subgroup 2, diamond disk and fine diamond bur; Subgroup 3, diamond disk and fine tungsten carbide bur; Subgroup 4, diamond disk and chemical stripping using 37% orthophosphoric acid in conjunction with a fine 3M finishing strip and Subgroup 5 (control), no stripping nor polishing. Qualitative (scanning electron microscopy) and quantitative (surface roughness test) assessments were performed. Surface roughness values (Ra) for permanent enamel were evaluated using the Welch analysis of variance (ANOVA).

Subgroup 1 (diamond disk and fine Sof-lex disc) produced the smoothest enamel surface and Subgroup 4 (chemical stripping) produced the roughest enamel surface.

All proximal stripping and polishing methods significantly roughened the enamel surfaces. The best results were obtained when the stripped enamel surfaces were polished and finished with fine Sof-lex discs.