The Efficacy of Nanohydroxyapatite and High Concentration Fluoride Containing Toothpastes on Dentin Hypersensitivity: A Scanning Electron Microscopy and EDX Study

This study examined the changes in dentinal tubules after treatment with a toothpaste containing nanohydroxy- apatite and another containing high concentration fluoride which is known to strengthen teeth. Experimental tooth samples were prepared by exposing the dentin surfaces using a pH cycling model to simulate the oral environment. The two toothpastes were applied to the dentin surfaces. After treatment, the teeth were exposed to pH cycling for 3 or 6 days. Using scanning electron microscopy, initial occlusion of the dental tubules was observed in the high concentration fluoride group. By Day 6, the number of occluded tubules increased in the nanohydroxyapatite group. Analysis of the levels of calcium (Ca), phosphorous (P) using electromagnetic radiation spectroscopy revealed that the proportion of Ca and P atoms prominently increased in both groups for 6 days. These findings demonstrated that a toothpaste containing nanohydroxyapatite effectively occluded dentinal tubules. This suggests that nanohydroxyapatite may be effective for dentin desensitization.