Evaluation of tea stain removal efficacy of ficin

Abstract

The aim of the present study was to investigate the stain removal efficacy and whitening effect of ficin with different concentrations comparing with commonly used whitening agents. Ninety enamel slices were obtained from bovine mandibular permanent incisors and randomly divided into 15 groups (n = 6), which were treated with five different concentrations of CP, STPP, and ficin respectively. Colour changes were measured before and after treatments based on the International Commission on Illumination (CIE) L* a* b* colour measurement system. The changes in the surface morphology of enamel slices before and after different treatments, and the degree of enamel damage after treatment with ficin were characterised by scanning electron microscopy (SEM) at different magnifications. The results show that when the concentration of CP and STPP was less than 0.8% and 8%, the change of ΔE (overall colour differences) was not significant (P > 0.05), but when the concentration of ficin was less than 0.1%, the change of ΔE was significant (P < 0.05). To study this issue, we performed dummy variable regression and confirmed that there was no significant difference in the ΔE between 0.1% and 0.2% ficin group (P = 0.089), and it was better than the other 13 groups (P < 0.05). Conclusively, we found that the tea stain removal efficacy of ficin was better than that of low-concentration CP and STPP which were originally introduced into whitening toothpaste as chemical whitening ingredients.