The Effect of Toothpaste Containing Nano-Hydroxyapatite on the Remineralization of the Enamel Surface. An In Vitro Study

The study material consisted of 90 human enamel samples, which were embedded in cylindrical acrylic blocks, washed, and polished. The samples were randomly divided into three groups (two test groups and one control group) in equal numbers. First, the microhardness of the enamel surface (SMH) was determined using the Vickers method, while surface roughness (Ra value) was measured with a profilometer. The enamel samples underwent preliminary demineralization to simulate the initial formation of carious lesions. Subsequently, the mean SMH and Ra values were determined again. After demineralization, half of each sample was coated with a protective varnish. The exposed fragment was subjected to a three-week cycle of pH fluctuations according to the protocol. The groups were as follows: NHAPF group – toothpaste containing nano-hydroxyapatite (Nano-HAP) and 1,450 ppm F; F group – toothpaste containing 1,450 ppm F; and P group (placebo) – distilled water. Upon completion of the treatment phase, the microhardness of the enamel and the roughness profile were measured again.