Efficacy of Popular Natural Dental Bleaching Products on Dental Enamel

The aim of this study was to evaluate the effect of natural products used empirically for dental bleaching on the color alteration (ΔE00), whitening index for dentistry (WID), surface gloss and microhardness of dental enamel. For this study 70 fragments of bovine teeth (6x6x2mm) were obtained and separated in five groups (n=14), according to the product used for the treatments: G1 (conventional toothpaste), G2 (charcoal), G3 (curcumin), G4 (banana peel) and G5 (16% carbamide peroxide gel). Initial color (Easyshade, VITA), surface gloss (Micro-Gloss 45, BYK Gardner), and microhardness (Micro Hardness Tester HMV-2, Shimadzu) readings were performed. For G1 to G4, treatments were performed using a simulated toothbrushing machine where the samples were brushed for 560 cycles (14 day of brushing T1) and 1200 cycles total (simulating 30 days of brushing T2). New readings were obtained after T1 and T2. For the G5 group, the treatment with carbamide peroxide gel were submitted on the fragments during 4 hours/day for 14 days, and then final readings were obtained. Regarding EΔ00, only G5 showed difference from other groups (p>0.5). For the WID analysis, after 14 days G3 (curcumin) showed lower whitening efficacy (p>0.5), and after 30 days there was no difference between groups (p<0.5) except for the carbamide peroxide group. Banana peel, curcumin and carbamide peroxide caused a decrease in the enamel gloss values after T1, different (p>0.5) from the charcoal and toothpaste groups. Charcoal resulted in the higher gloss values in T2, different (p>0.5) from all groups, except toothpaste. Carbamide peroxide showed the lower microhardness values, similar (p<0.5) to the banana peel and curcumin groups. Considering the results found, it can be concluded that natural products that have been used for dental bleaching purposes did not present effectiveness on the enamel color alteration. Furthermore, banana peel and curcumin caused a decrease in microhardness similar to carbamide peroxide.