A New Laboratory Whitening Method to Evaluate Toothpastes

Purpose: During the conduct of standard tooth brushing studies with toothpaste products it was observed that artificial plaque whitening occurred where there was no toothbrush bristle contact. The purpose of this research was to assess artificial plaque whitening after the application of commercially available whitening toothpastes, without brushing.Methods: Six toothpastes with labeled whitening claims were evaluated. Each toothpaste was placed into a prophylaxis cup, inverted onto the artificial plaque substrate and topped with a 50 g weight. The toothpaste products were evaluated at full strength and after diluting 1:3 with water. A Whitening Index (WI) was determined by visually evaluating the increase in whitening of the plaque using a 0 - 2 scale. Significant differences between the toothpastes were determined using t-tests, assuming unequal variances.Results: Two toothpastes containing hydrogen peroxide had significantly greater WI scores compared to two calcium peroxide-containing toothpastes and two peroxide-free toothpastes (p < 0.001) when tested at full strength or diluted 1:3. The two toothpastes containing calcium peroxide, tested undiluted, exhibited significantly higher whitening means than the peroxide-free whitening toothpastes (p < 0.05).Clinical Significance: It is important for dental health providers to have scientific evidence of efficacy for whitening toothpastes so as to advise patients as to which product will best meet their needs for tooth whitening. A new method has been developed and has been shown to detect significant differences in whitening scores between toothpastes containing different peroxide compounds and peroxide-free products.