Research about bovine teeth brightness with using dentifrice slurry including nano-hydroxyapatite

Hydroxyapatite has high affinity rate with organic substance in an oral cavity, therefore lately nano-sized hydroxyapatite is extensively researched to increase affinity to tooth and remineralization. The objective of this research is indirectly to investigate the effect of nano-hydroxyapatite on remineralization using valuation about brightness of the bovine tooth. We have designed in vitro test for this purpose. The bovine teeth are sliced into human teeth size then the baseline brightness of total 90 teeth is measured and assigned into 3 groups (30 teeth per group) by cross-matching according to the brightness. These samples were embedded into resin mold and underwent mechanical brushing during fixed schedule. The brightness of teeth are measured and compared among 3 groups. Each dentifrice used in the experiment is composed of B.S.I group (15% Calcium Carbonate, precipitated-CaCo₃) with abrasion rate of 100, Test □ group (15% Sodium Metaphosphate, insoluble-NaPo₃), Test □ group (15% Nano-hydroxyapate-Ca₁₀(PO₄)₆(OH)₂). After 10,000 strokes of mechanical brushing with each group sample teeth brightness is measured for 2^nd time. The teeth brightness is measured again for 3^rd time. We have compared with average of brightness before and after test in group and each other 3 group. The brightness of teeth was maintained in test group II, however in other group the whiteness achieved through brushing was lost (p<;;0.01). It is concluded that the dentifrice including the nanohydroxyapatite is replaced with the organic substance in enamel resulting the increase in brightness, which leads to the increase the enamel remineralization in teeth and result to decrease in caries susceptibility.