Dentinal Tubule Occluding Capability Of Hydroxyapatite Containing Toothpaste

To investigate hydroxyapatite (HAP) containing toothpaste on dentine tubule occlusion. 1 mm thick bovine dentin were prepared. All dentin discs were etched with 40% phosphoric acid to expose dentinal tubules. Samples were randomly divided into two groups: test group (a commercial Repair & Protect Toothpaste containing HAP, potassium citrate and NaF) and control group (without HAP and potassium citrate, with NaF). The dentin discs were brushed with toothpaste every morning and evening for 2 min each time, and were kept in an artificial saliva incubator at 37 °C for the rest of the time. After 3 and 7 days, the surface and cross-section morphology were observed by SEM. After 3 and 7 days, the occlusion rates of dentinal tubules in the experimental group were 96.0 ± 2.1% and 99.7 ± 0.7%, which were significantly higher than those in the control group (43.5 ± 10.1% and 76.4 ± 7.3%). Mineralized layer with average thickness of 3.10 and 6.37 μm were formed on the dentin surface after 3 and 7 days, while no obvious mineralized layer was observed in the control group. The commercial Repair & Protect Toothpaste containing HAP and potassium citrate can effectively occlude the exposed dentinal tubules and form a mineralized layer on the dentin surface.