IADR Abstract Archives
Combined Effects of Nano-hydroxyapatite and Fluoride on Inhibiting Dental Erosion
Objectives: The aim of this study was to evaluate combined effects of nano-hydroxyapatite (nano-HA) and fluoride on inhibiting dental erosion.
Methods: Enamel blocks(4mm*4mm*3mm) were prepared from sound bovine teeth, and embeded in acylic resin. The specimen were covered by an acid-resistant nail varnish exposing an area of 3mm*3mm in the centre. Forty enamel blocks were randomly divided into 4 groups. The experimental solutions were distilled and deionised water(the control group), 1000ppm NaF(group 1), 10%(wt.%) nano-HA aqueous slurry in distilled water(pH 7.0, group 2), 1000ppm NaF solution with 10%(wt.%) nano-HA aqueous slurry(pH 7.0, group 3). The enamel specimens were treated with pH-cycling schedule which had 5 min 0.3% citric acid treatment and 2 hour experimental solution treatment respectively twice a day for 7 days, the specimens were stored in artificial saliva overnight at 25°C. Calcium concentration in the citric acid solutions were determined using atomic absorption spectrometer. Vickers hardness was determined on the enamel specimens before and after cycling with a microhardness indentor at 50g load for 15s.
Results: The lose of calcium in the nano-HA and fluoride combination group(0.12±0.25 mmol/L) was the lowest among the four groups, and was statistically significant lower than that of the control group (0.65±0.68mmol/L, P<0.001) , group 1(0.28±0.25 mmol/L, P<0.05)and group2(0.35±0.31 mmol/L, P<0.05). Surface hardness obtained from microhardness tests revealed that all the treatment groups had significantly greater effect on inhibiting erosion than that of the control group. The variation of hardness of the lesion in the nano-HA and fluoride combination group(21.1%) was the lowest among the four groups, and was statistically significant lower than that of the control group (62.6%, P<0.001) , group1(35.4%, P<0.05) and group 2(42.8%, P<0.05).
Conclusions: There was a significant synergistic effect of combined fluoride and nano-HA treatment on inhibiting the erosion of the enamel.
Methods: Enamel blocks(4mm*4mm*3mm) were prepared from sound bovine teeth, and embeded in acylic resin. The specimen were covered by an acid-resistant nail varnish exposing an area of 3mm*3mm in the centre. Forty enamel blocks were randomly divided into 4 groups. The experimental solutions were distilled and deionised water(the control group), 1000ppm NaF(group 1), 10%(wt.%) nano-HA aqueous slurry in distilled water(pH 7.0, group 2), 1000ppm NaF solution with 10%(wt.%) nano-HA aqueous slurry(pH 7.0, group 3). The enamel specimens were treated with pH-cycling schedule which had 5 min 0.3% citric acid treatment and 2 hour experimental solution treatment respectively twice a day for 7 days, the specimens were stored in artificial saliva overnight at 25°C. Calcium concentration in the citric acid solutions were determined using atomic absorption spectrometer. Vickers hardness was determined on the enamel specimens before and after cycling with a microhardness indentor at 50g load for 15s.
Results: The lose of calcium in the nano-HA and fluoride combination group(0.12±0.25 mmol/L) was the lowest among the four groups, and was statistically significant lower than that of the control group (0.65±0.68mmol/L, P<0.001) , group 1(0.28±0.25 mmol/L, P<0.05)and group2(0.35±0.31 mmol/L, P<0.05). Surface hardness obtained from microhardness tests revealed that all the treatment groups had significantly greater effect on inhibiting erosion than that of the control group. The variation of hardness of the lesion in the nano-HA and fluoride combination group(21.1%) was the lowest among the four groups, and was statistically significant lower than that of the control group (62.6%, P<0.001) , group1(35.4%, P<0.05) and group 2(42.8%, P<0.05).
Conclusions: There was a significant synergistic effect of combined fluoride and nano-HA treatment on inhibiting the erosion of the enamel.