Methods: The study encompassed two stages; stain formation and removal. On the buccal surface of 12 extracted bovine teeth, a 12mm2 varnish window was created. Surface stain was developed by immersion in artificial saliva, Chlorhexidine® mouthwash and tea solutions respectively for 8 cycles of 2 minutes in each solution. QLF was used to monitor the level of stain after each cycle; this level was then quantified using the QLF software. The mean ΔQ values (percentage fluorescence loss multiplied by the area) were recorded and the percentage stain uptake thus calculated.
Stain removal comprised immersing the tooth samples into toothpaste preparations: Colgate Whitening® and Asda Smartprice®, as well as controls of sodium perborate and distilled water. Each sample was subjected to 10 minutes immersion in the one of the above solutions (5 cycles of two minutes). Again, QLF was used to monitor changes in surface staining after each cycle. Mean ΔQ values and percentage stain removal were calculated.
Analysis of variance (ANOVA) tests were then used to identify any statistical significance between results.
Results: The results suggest that QLF can be used successfully to quantify stain uptake and removal. There were statistical differences between all the test solutions in stain removal. There was no statistical significance between stain removal for the positive control and toothpaste solutions.
Conclusion: All the test preparations removed stain to some extent; however the toothpaste solutions and positive control appeared to remove stain to a greater degree. Colgate Whitening Asda Smartprice appeared to have similar stain removal properties.