Fluoride-amorphous calcium phosphate and biomimetic nano-hydroxyapatite for enamel remineralization: An in-vitro study of surface microhardness and composition

Aim: Fluoride-Amorphous Calcium Phosphate and Biomimetic Nano-Hydroxyapatite for Enamel Remineralization; An In-Vitro Study of Surface Microhardness and Composition. Material and methods: Ninety-six extracted human premolars with sound buccal surface were divided using a randomization computer-generating software into four groups; Group I (control) sound untreated enamel, Group II (demineralized) demineralized to create white spot lesions, Group III (biom-n-HA) demineralized and then treated with biomimetic nanohydroxyapatite cream, and Group IV (F-ACP) demineralized and then treated using Fluoride-Amorphous Calcium Phosphate varnish. Each group was divided into two subgroups; subgroup "A" evaluated for mineral content using energy dispersive x-ray spectroscopy (EDX) and for surface microhardness using the Vickers microhardness test and Subgroup "B" evaluated for white spot lesion depth using a polarized light microscope (PLM). Results: The highest microhardness (VHN) was found in the (F-ACP) group (mean = 428.61 +/- 54.43) and then in the (Biom-n-HA) group (mean = 408.11 +/- 70.16) followed by the (Control) group (mean = 402.13 +/- 53.40) with no significant difference between them and finally in the significantly different (Demineralized) group (mean = 256.99 +/- 45.83). The weight percentage of Ca (30.29 +/- 1.04 and 33.44 +/- 1.07) and Ca/P ratio (1.87 +/- 0.06 and 2.03 +/- 0.05) were significantly different between Group III and Group IV respectively. PLM measurements in Group II (198.83 mu m), Group III (60.17 mu m), and Group IV (26.33 mu m) were significantly different. Conclusions: Both the (Biom-n-HA) cream and the (F-ACP) varnish showed promising results for enamel remineralization. The increased enamel surface microhardness was consistent with the mineral content and the changes in the birefringence.