Micro Hardness Of Bleached Human Enamel Following Application Of Conventional Versus Nano Active Bioglass: An Invitro Study

Objectives: The aim of this study was to compare the effect of conventional vesrsus nanosized bioactive glass on the microhardness values of bleached enamel.
Methods: Forty-five fresh extracted human incisors were divided into three main groups (15 each) according to the bleaching technique (B); unbleached (B0) as a Control, light activated bleaching (B1) and chemical activated bleaching (B2). Each group was further divided equally into three subgroups (5 each) according to application of remineralizing agent (R); either conventional bioactive glass (R1), nano bioactive glass (R2) and without application of any remineralizing agent as a control (R0). Teeth bleaching was done as per the manufacturer’s instructions, while, remineralizing agents were applied according to wang et al 2011. Microhardness assessment was done after bleaching as well as after remineralization using Digital Display Vickers Microhardness Tester.
Results: The unbleached group showed the highest mean microhardness followed by chemically activated bleaching group, then the light activated bleaching group. Regarding remineralization; nano bioactive glass groups showed higher microhardness results than conventional bioactive glass groups.
Conclusions: Bleaching has a deleterious effect on enamel microhardness. Bioactive glass can counter act the adverse effect of bleaching on enamel. Nanobioactive glass is a promising material for remineralization