Effect of resin infiltration and bleaching on surface roughness and microhardness of human enamel with induced white spot lesions

Abstract

Objective: To comparatively evaluate the effect of resin infiltration, bleaching and bleaching followed by resin infiltration on the surface roughness and microhardness of human enamel with induced white spot lesions (WSLs) and their resistance to acidic challenge. Material and Methods: Sixty human specimens were randomly divided into three groups (n=20) according to the treatment modality applied; group I Icon® resin infiltration, group II bleaching and group III bleaching followed by Icon® resin infiltration. For each treatment modality, 10 specimens were tested for surface roughness and another 10 for microhardness. WSLs were artificially induced in all specimens and after treatment, all specimens were subjected to acidic challenge. Surface roughness was measured by the tapping mode of the atomic force microscope (AFM) and microhardness was measured by digital Vickers hardness tester at baseline, after induction of WSLs, after treatment and after acidic challenge. Results: Groups I and III showed significant reduction in surface roughness after treatment, while group II showed significant increase. Groups I and III showed significant increase in the microhardness after treatment, while group II showed insignificant increase. The three tested groups showed significant increase in surface roughness values and significant reduction in microhardness after acidic challenge. Conclusion: Resin infiltration and bleaching followed by resin infiltration reduced the surface roughness and enhanced the microhardness of the WSLs. The three treatment modalities failed to resist acidic challenge resulting in increasing surface roughness and reducing microhardness.