Sensitivity Reduction Mechanism of Calcium and Phosphate Delivering Toothpaste

Tooth Sensitivity reduction can be achieved by occluding dentinal tubules. However, ingredients in conventional toothpastes interfere with a standard tubule occlusion assessment method (Pashley et al). Objective: The purpose of this study was to assess a new desensitizing fluoride-toothpaste, delivering calcium and phosphate ions, for its ability to occlude dentinal tubules using an alternative dye penetration technique. Method: Eighteen cleaned, intact teeth were perfectly sealed with enamel paint (Rustoleum®). Windows, 100-200µ deep, were opened on opposite sides of each tooth at the dento-enamel junction and briefly etched using 20% polyacrylic acid (Novean GoodRight K702®), finally rinsing in water. One batch of teeth was treated 8 times with a 1:3 slurry of Enamel Care Sensitive(R), a new British sensitivity toothpaste formulated without potassium nitrate (ECS), and one in a placebo slurry (P) for ˝ hour. A 0.85% aq. solution of Acid Red Fuschin dye was applied to each window and allowed to dry for 3 hours followed by a brief rinse and sectioning across the windows. Results: After sectioning, virtually no dye penetration can be seen in those teeth treated with ECS but extensive penetration was visible in P-treated teeth. Subjective comparisons and pixel counts both showed ECS to minimize dye penetration more effectively than placebo (p<0.001). Conclusion: Tubule occlusion due to calcium and phosphate ions from the desensitizing toothpaste accounts for its tooth-desensitizing efficacy. The dye penetration technique may be useful for evaluating tubule occlusion by other desensitizing toothpastes.