In Vitro Measurement of the Instant Whitening Efficacy of Commercial Dentifrices

Objectives: To evaluate the in-vitro instant whitening efficacy of commercially available dentifrices.

Methods: 27 human molars were mounted in acrylic blocks, three blocks per tray. Baseline CieLAB values were measured with a spectrophotometer (Spectroshade Micro, MHT). The teeth were soaked in saliva for 15 min. Saliva was removed and six grams of dentifrice and 12mL of new saliva were added to each tray. The teeth were brushed for two minutes with settings of 120 strokes/min and 250g on a brushing machine. The toothpaste slurry was rinsed from the teeth using 100 mL of deionized water and CieLAB values were measured. Saliva was added to each tray and the teeth were soaked at 37 ᵒC for 10 min. At this time the saliva was removed and Cielab values measured. This was repeated at 30 and 60 minutes. The products evaluated in this study were a commercial dentifrice containing blue pigment and PVM/MA co-polymer, and a commercial dentifrice containing blue pigment. The change in whiteness is reported as ΔWIO. Analysis of variance was used to compare the mean ΔWIO values.

Results: After the initial brushing the ΔWIO for the formula with blue pigment was 4.4+2.4, at 10 min 4.1+2.6, at 30 min 2.8+2.9, and at 60 min 2.3+3.0. After the initial brushing the ΔWIO for the formula with blue pigment and PVM/MA co-polymer was 2.4+3.2, at 10 min 1.7+1.7, at 30 min 1.4+2.9, and at 60 min 1.3+2.3. At all time points the ΔWIO for the formula with blue pigment was significantly greater than for the formula with blue pigment and PVM/MA co-polymer (p<0.05).
Conclusions: This in-vitro study suggests that the formula containing blue pigment can deliver better instant whitening than the formula with blue pigment and PVM/MA co-polymer after only one application.