Comparative efficacy of titanium dioxide nanoparticles loaded carboxymethyl cellulose and hydrogen peroxide gel on tooth whitening: An in-vitro study

In this study we evaluated the photocatalytic activity and dye degradation of blue light-activated and UV-activated carboxymethylcellulose gel containing titanium dioxide nanoparticles and compared with 40% hydrogen peroxide bleaching effect to reach to a new strategy that has most efficiency with minimal side effects. The effective concentration of carboxymethylcellulose gel containing TiO2 nanoparticles was determined. The color of the main samples was measured at first, after staining with coffee and after the bleaching process by colorimeter. E1, E2, E3 were recorded and ΔE1, ΔE2 were calculated. Samples were divided into eight groups, each containing six. In three groups, the bleaching effect of CMC gel containing TiO2 nanoparticles irradiated with UV-C was investigated after one, two, and three times exposure to the teeth. In the other three groups, the bleaching effect of CMC gel containing TiO2 nanoparticles irradiated with light cure was investigated after one, two, and three times exposure to the teeth. The results were compared with two control groups CMC and H2O2. The effective concentration of carboxymethylcellulose gel containing TiO2 nanoparticles was 20%. ΔE2  result for H2O2 control group was 6.34 and for CMC control group was 2.54. The values of ΔE2 in groups were exposed once, twice and three times to CMC gel containing TiO2 nanoparticles that were activated by UV were 3.83, 4.19, 4.42 respectively and ΔE2 results in groups were exposed once, twice and three times to CMC gel containing TiO2 nanoparticles that were activated by blue-light were 4.45, 5.03, 5.55 respectively.  The greatest value of ΔE2 belonged to the bleached group with hydrogen peroxide gel with ΔE2: 6.34 and after that related to the group activated three times with blue light with ΔE2: 5.55.  All groups except the CMC control group showed ΔE2 higher than 3.3.