Laboratory Toothpaste Cleaning Power Method Parameters

Objective: This study was to review individual characteristics of the established toothpaste Cleaning Power Method (Stookey et al, JDR 61:1236,1984). While this laboratory method has an established correlation with clinical studies, variance of results is higher than desired. Method characteristics more likely to affect the variance were reviewed including tooth surface preparation, pre-stain etching, staining procedure, color measurement of stain, specific site measurements, dilution of toothpaste slurry and number of strokes to remove the stain. While it may be desirable to use the natural surface for specific studies, the removal of the outer, often ridged, surface provided a more consistent and flatter surface for subsequent staining and measurement. Method: Cycling the teeth through the staining medium and under infrared heat lamps with a warm airflow reduced significantly the time required to stain the teeth. This approach produced a multi-layered stain that did not materially affect the stain or its removal. Smaller diameter colorimeter measuring ports coupled with a microscope micrometer positioning device increase the ability to measure the same site before and after treatments and minimized the need for a flatter tooth surface. Results: Stain removal reached a plateau at 3,000 double strokes, thus 3,000 rather than the recommended 1,000 strokes would reduce the variance of results. Tea stain was pH stable, thus a toothpaste pH of 4.5 to 10 will have little effect upon stain removal. Dilution of toothpaste slurry affected the cleaning power of soluble abrasive systems. Conclusion: The bovine tooth Cleaning Power Method remains the preferred laboratory method to assess toothpaste functionality. Supported in part by Church and Dwight. hefferen@ukans.edu