Whitening Effect of Juglans regia Dry Husk Extract on Primary and Permanent Teeth

Abstract

Walnut is a common member of the family Juglandaceae. Recently, the evaluation of the phenolic content and antioxidant activity of the parts of walnut has received increased interest. Many reasons are responsible for teeth discolouration because teeth can absorb ingredients from tea, coffee, and food. Stains from these ingredients could stay in the porous enamel layer. Traditional whitening chemicals have some side effects, the most common of which is tooth sensitivity and mild or moderate gingival irritation. The aims of this comparative experimental study were to evaluate the whitening effect of Juglans regia dry husk extract and compare it with that of traditional prophylactic pumice. Forty human teeth were collected. Amongst these teeth, 20 were permanent, and the other 20 were primary. Each group was randomly divided into a study group (treated with dry husk extract) and a control group (treated with traditional pumice). Tooth colour was measured with Easy VitaShade Advanced 4.0, and the readings of lightness, chroma, and hue ( $a^{\ast }$ represents the green to red axis and $b^{\ast }$ represents the blue to yellow axis) were documented for each tooth before and after polishing. A statistical analysis was performed using the Statistical Package for Social Science (version 22; Chicago, Illinois, USA). Data were analysed using Shapiro–Wilk, Wilcoxon sum rank, and Wilcoxon signed rank tests, and the level of significance was set to 0.05. A normality test was conducted using the Shapiro–Wilk test, and it showed that the colour variables were not normally distributed. With regard to tooth lightness, significant differences were observed in the primary and permanent teeth and Juglans regia exerted a much better whitening effect than pumice at $p<0.05$ . This study supports the use of Juglans regia dry husk extract in dentistry as a natural product with a whitening effect. It has utilisation potential in dentistry due to its beneficial properties and highly active components.