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 resininfiltration 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 randomlydivided 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, 10specimens were tested for surface roughness and another 10 for microhardness. WSLs were artificially inducedin all specimens and after treatment, all specimens were subjected to acidic challenge. Surface roughness wasmeasured by the tapping mode of the atomic force microscope (AFM) and microhardness was measured bydigital 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 showedsignificant increase. Groups I and III showed significant increase in the microhardness after treatment, whilegroup II showed insignificant increase. The three tested groups showed significant increase in surface roughnessvalues and significant reduction in microhardness after acidic challenge. Conclusion: Resin infiltration andbleaching followed by resin infiltration reduced the surface roughness and enhanced the microhardness of theWSLs. The three treatment modalities failed to resist acidic challenge resulting in increasing surface roughnessand reducing microhardness.KEYWORDSAFM; Bleaching; Microhardness; Resin infiltration; White spot lesions.