Dental enamel roughness with different acid etching times: Atomic force microscopy study

Abstract

Abstract Objective: An important characteristic of human dental enamel not yet studied in detail is its surface roughness in mesoscopic scale. This study evaluated quantitatively and qualitatively the surface topography of acid etched enamel with different etching times. Materials and Methods: Ninety-six human maxillary bicuspids were randomly distributed into three groups (n=32): T0 (control), pumiced; T15, 35% phosphoric acid etched enamel for 15 s; T30, 35% phosphoric acid etched enamel for 30 s. Roughness measurements Ra, Rz and root mean square (RMS) and 3D images of enamel′s topography were obtained with atomic force microscopy (AFM), which is a powerful technique to obtain direct measurements on microscale features. Results and Conclusions: Roughness variables Ra, Rz and RMS presented statistically significant differences to all groups (P<0.000), with values increasing with etching time. This increase was greater from T0 to T15 than from T15 to T30. Enamel surface alterations T15 to T30 occur mainly due to increase in height and deepening of prisms central region.