An in vitro evaluation of the effect of fluoride products on white spot lesion remineralization.

PURPOSE: To compare the effect of combinations of fluoride (F) products on remineralization of caries-like lesions. METHODS: Demineralized human enamel specimens were assessed by surface microhardness (SMH), stratified and allocated to five treatments groups: (1) Toothpaste containing 1% nano hydroxyapatite (HAP) + 1,450 ppm F; (2) Tooth mousse containing 10% casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) + 900 ppm F plus F toothpaste (1,450 ppm F as NaF); (3) F varnish containing 22,600 ppm F plus F toothpaste (1,450 ppm F as NaF); (4) F toothpaste (1,450 ppm F as NaF); and (5) placebo--distilled water (P). Each group was treated in a 21-day pH-cycling model. Groups 1, 4 and 5 were treated 2x/day. In Group 3, the tooth mousse was administered 1x/day plus 2x/day F toothpaste treatment. In Group 4, F varnish was administered 1x/week plus 2x/day treatment with F toothpaste. After cycling, SMH was re-measured and cross-sectional microhardness measurements were taken. RESULTS: Groups 1-4 produced significant rehardening of enamel. In the superficial layer (25-50 µm deep) significantly higher mineralization (up to 83%, by Volume (V), P < 0.0001) was achieved for Groups 2 and 3. In the area of 75-100 µm deep, the highest mineralization was observed for Groups 1 and 4 (V% = 68-83%).

The effect of nano-hydroxyapatite toothpaste on enamel surface remineralization. An in vitro study.

PURPOSE: To compare, in vitro, the surface remineralization effect of two fluoride dentifrices. METHODS: 90 human enamel specimens, embedded in cylindrical acrylic blocks, washed and polished, served as a study material. The specimens were randomly assigned in equal numbers to the three groups (two test and one control). Initially the microhardness of the enamel surface (SMH) was assessed by Vickers method, while a profilometer was used to evaluate the surface roughness (Ra value). The enamel specimens were subjected to the preliminary demineralization, simulating the initial carious lesion formation. Subsequently, mean SMH and Ra values were re-assessed. Upon demineralization, one half of each specimen was covered with a protective varnish. The exposed fragment underwent the 3-week cycle of pH changes, according to the protocol. The groups were as follows: NHAPF group--toothpaste containing nanohydroxyapatite (nano HAP) and 1,450 ppm F; F group--toothpaste containing 1,450 ppm; and P group (placebo)--distilled water. Upon completion of the treatment period, the enamel microhardness and roughness profile were re-measured. RESULTS: The demineralization procedure resulted in statistically significant reduction of SMH level in all the groups, and the mean post demineralization values were in the range of 49.7 VHN to 51.2 VHN. Remineralization therapies led to statistically significant increase of enamel SMH value (P < 0.0001). None of the groups reached their original baseline level of SMH following the remineralization therapy.