Comparative evaluation of application of 2% sodium fluoride, 0.4% stannous fluoride, 1.23% apf on enamel micro-hardness using 16% carbamide peroxide bleaching agent by vhn - an in vitro study

Introduction: Bleaching is simplest, least invasive and least expensive means available to lighten discoloured teeth and diminish and eliminate many stains in both vital and nonvital teeth. Aim- To compare different fluoride gel applications on micro-hardness of bleached teeth using Vicker’s Hardness profiles. Materials and method: 80 extracted human maxillary anterior teeth were selected. Roots of selected teeth were sectioned horizontally 2 mm below the level of CEJ and crown were sectioned labiopalatally. Samples were randomly divided into 3 experimental groups and one control group, 20 samples in each group and stored in artificial saliva for 10 days prior to the bleaching procedure as well as in between 2 successive bleaching procedure. Microhardness testing was done preoperative, post bleaching and post fluoride application. Bleaching was carried out for 21 days for 4 hours. Allotted fluoride application was done on 21st day for 5 minutes group A- Control, Group B- 2% Sodium Fluoride, Group C- 0.4% Stannous fluoride, Group D- 1.23% APF. Results and Conclusion: Application of bleaching agents led to decrease in microhardness, whereas application of fluorides post bleaching helped to restore the microhardness equal to the preoperative values. APF led to highest increase in the microhardness post bleaching.