IADR Abstract Archives
In vitro method for evaluating extrinsic stain prevention and removal
In vitro method for evaluating extrinsic stain prevention and removal
J. GORDON
GlaxoSmithKline Consumer Healthcare, Weybridge, UK
Objective: To develop a simple and rapid in vitro stain prevention/removal method that is predictive of clinical outcome. Method: The method was based on an in vivo forced stain model (Claydon et al. 2004, J. Clin. Periodontol. 31: 1088 -1091). Naturally stained bovine teeth were pre-brushed with a standard toothpaste to remove loose extrinsic stain. Baseline L*a*b* was taken for each tooth using a Hunter LabScan XE spectrophotometer. The teeth were randomised and allocated to test groups (n=7). Aquafresh Multiaction+Whitening (AMW) and Rembrandt Whitening (RW) were slurried in water (3g paste:10g water) and applied to the teeth. The teeth were then exposed to a repeated chlorhexidine/tea cycle. L*a*b* was re-measured after every 4th cycle. After every 8th cycle, the teeth were brushed with water on a brushing machine (100 strokes) and the L*a*b* re-measured. The procedure was repeated twice. The change in L*a*b* was calculated. A one-way ANOVA (95% LSD) was carried out using StatGraphics Plus software.
Results:
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Mean change in L* (± s.d) |
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Stain cycles |
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4 |
8 (pre-brushing) |
8 (post-brushing) |
12 |
16 (pre-brushing) |
16 (post-brushing) |
|
AMW |
-5.41 (0.73) |
-6.00 (0.75) |
-3.17 (1.35) |
-6.76 (1.77) |
-5.90 (1.01) |
-2.53 (0.77) |
|
RW |
-7.88 (1.86) |
-13.24 (2.66) |
-5.68 (2.13) |
-10.50 (2.30) |
-14.08 (2.67) |
-6.34 (4.65) |
|
Water |
-7.79 (0.76) |
-12.83 (1.19) |
-7.24 (2.49) |
-11.51 (2.14) |
-15.61 (2.19) |
-8.52 (3.38) |
In vitro there was a statistically significant difference between AMW and RW at every time point. There was statistically, no significant difference between RW and water at any time point. Conclusions: AMW inhibited stain build up and aided stain removal by brushing compared to RW and water controls. This in vitro method correlates well with the results from a clinical study (Claydon et al. 2004). However, the discrimination between treatments in the in vitro model was greater than that in vivo.