Color stability and microhardness alteration of irradiated dental enamel treated with a high fluoride concentration toothpaste

Radiotherapy (RT) is a kind of head and neck cancer (HNC) treatment, which is associated to the habit of smoking and can develop collateral effects in the oral cavity, such as the increase of caries prevalence. This study evaluated the color alteration, the microhardness, and the remineralizing potential of high fluoride concentration toothpastes on irradiated teeth.Forty bovine teeth were used (6 × 6 × 2 mm) and after color (EasyShade, VITA) and microhardness initial readings were separated into two groups: exposed to cigarette smoke and non-exposed. All samples were submitted to RT (30 Gy) and to cariogenic challenge. New color and microhardness readings were done. After RT (60 Gy), the samples were submitted to simulated toothbrushing (73,000 cycles = 5 years of brushing) with two different toothpastes: conventional (1450 ppm) and high fluoride concentration (5000 ppm). Final color and microhardness readings were done after brushing. Data were analyzed with 2-way ANOVA with repeated measures and Tukey's test (p < .05).There was no color difference after RT, nor after brushing (p > .05). However, after brushing, microhardness values increased for the samples treated with high fluoride concentration toothpaste (p < .05).Radiotherapy did not influence the teeth color, and the high fluoride concentration toothpaste presented remineralizing potential; therefore, it could be used on the caries prevention related to HNC radiation.Considering its remineralizing potential, toothpastes with high fluoride concentration could be a proper alternative for caries prevention in patients undergoing radiotherapy.