The Pellicle Cleaning Ratio of Three Whitening Dentifrices

The aim of this in vitro study was to evaluate the Pellicle Cleaning Ratio (PCR) of three commercial whitening dentifrices.

Method:

One modified method of tooth staining was used. 72 Bovine enamel specimens with a diameter of 5 mm (n = 18 for each treatment group) were used for this study. The specimens were polished and thereafter stored in human saliva for 2 min, 4 min in 0.2% chlorhexidine and 4 min in black tea (3g in 100ml^-1water at 50°C). After saliva and chlorhexidine exposition, the specimens were placed in distilled water for 30 sec. This cycle was repeated 8 times per hour. Specimens were brushed for 1000 strokes at a 1.5 N load. All treatments were performed on an automatic brushing machine using standard ADA toothbrushes and slurries. The three dentifrices were Colgate Max White (C:RDA=144), Blend a med 3D White (B:RDA=143), and Eurodont Fresh & White (E:RDA=80). The standard dentifrice was a calcium pyrophosphate preparation according to ISO 11609 (RDA = 100). Specimens’ colours (L indicates light / dark) were evaluated by using a chromameter (Shofu ShadeEye NCC, Shofu Inc. Kyoto, Japan) before, after discolouration (initial), and after brushing (final). Specimens’ treatment effects were assessed and relative efficacy compared to the reference pyrophosphate abrasive was calculated as follows:

{L*_tf-L*_ti/ΔL_{(avg. f-i)ADA Std}}x100
L =L* Value; t=test; f=final; i=initial

Data analysis was accomplished using the Kruskal Wallis Test und Mann Whitney U Test (p<0.05).

Result: The mean (standard deviation) of PCR value was 101.71(12.72) for C; 105.33(12.35) for B and 84.93(13.68) for E. No statistically significant differences were found between C and B, however  C and B were found to be more effective than E.

Conclusion:

Therefore, within the limitations of this study, the whitening dentifrices B and C with RDA >100 were equally effective in stain removal.