Effect of fluoride therapy on remineralization and whiting of bleached enamel

Objective To evaluate the effect of fluorin dentifrice on the microhardness and whiting of dental enamel bleached with different concentration bleachers.Methods 6%carbamide peroxide(CP)and 30%CP were selected as bleachers.Twenty undefected molars were subjected to 3 groups.Groups A and B.which composed of 8 teeth each,were tested and group C was the control one.Group A(buccal surface)and group B(buccal surface)were treated with 6%CP.Group A (lingual surface)and group B(lingual surface)were treated with 30%CP.They were bleached 30 min every day for two weeks.The teeth in group B were brushed with fluorin dentifrice for 15 min after bleached every time and then all tested samples were kept in the artificial saliva at 37℃.Vickers microhardness of all teeth and color measurement of groups A and B were made before and at the end of bleaching procedure.Results The difference of microhardness values between the bleached and control samples were not statistically significant(P＞0.05).Brushed with fluorin agent significantly increased the hardness of enamelin group B(P＜0.05).The color change was not significant between bleached samples.Conclusion Using fluoride in the interphase of bleaching makes this therapy safer,and does not affect the whitening effect. Key words: Tooth bleaching; Fluoride; Microhardness; Color