Clinical Functionality of Seven Grades of Sodium Bicarbonate Crystalline Powder in the Same Toothpaste Formulation

Objective: This study was to measure the dentin abrasivity and cleaning power of seven grades of sodium bicarbonate (1, 1.5, 2, 3, 5, MP and spheronized) in the same toothpaste formulation in 1:1 aqueous slurry. Methods: The dentin abrasivity profilometric method used as a substrate ICI Lucite® cast acrylic cut into 3 X 26 X 50 mm strips. The acrylic was brushed in a cross-brushing motion with the ADA Reference medium hard, flat profile toothbrush with 150 gm load (JDR 55:563, 1976). Mahr Federal Surfanalyzer 5000® Profilometer was used to measure surface wear and other surface characteristics before and after brushing (JDR 79:469, 2001). The cleaning power method (Stookey et. al. 61:1236, 1982) used etched bovine teeth stained with tea (Wülknitz, Adv Dent Res 11:576, 1997). Calcium Pyrophosphate was used as a reference for both abrasivity and cleaning power phases of the study. Results: The dentin abrasivity of the seven grades ranged from 6 to 19% of the abrasivity reference. Post brushing profilometry scans indicated that the sodium bicarbonate pastes had much less effect than the abrasivity reference, e.g., surface roughness for grade 3 paste was 1/5th the abrasivity reference. The cleaning power of the seven pastes ranged from 42 to 88% of the cleaning power reference. The ratio of cleaning power to abrasivity ranged from 2.3 to 12.0 indicating that sodium bicarbonate toothpaste achieved more cleaning with less abrasion. Conclusion: Laboratory methods designed to measure the abrasivity and cleaning power of toothpaste indicated that sodium bicarbonate cleaned stain tooth surfaces with very little abrasion with methods designed to measure mechanical cleaning. It is probable that chemical cleaning is contributing to the total cleaning observed. This study was supported in part by Church & Dwight Company, Inc. hefferen@ku.edu