In Vitro Remineralization of Acid-etched Bovine Enamel with Amino Acids/Hydroxyapatite Composite

doi:10.15541/jim20190027

Abstract

Abstract:

Remineralization of early enamel caries lesions plays a crucial role in prevention and restoration of dental caries. Based on the crucial amino acids contained in enamel matrix, amino acids /hydroxyapatite (AA/HAP) composite was synthesized in the presence of 10 mmol/L glycine, 10 mmol/L L-serine and 5 mmol/L L-aspartic acid. The physical, chemical and biological properties of the composite were characterized. And its remineralization effect on acid-etched bovine enamel was evaluated. Under the inhibition properties of amino acids, the composite has lower crystallinity and higher biocompatibility compared to the hydroxyapatite (HAP) without amino acids. In vitro remineralization of acid-etched bovine enamel using AA/HAP was conducted in artificial saliva. After remineralization, the surface and cross-section morphology, the components, and the mechanical property of bovine enamel samples were characterized, respectively. The results showed that the AA/HAP could induce the restoration of both surface and subsurface enamel lesions. The amino acids released from the composite could adsorb on the organic matrix residues and induce the formation of parallel arranged HAP crystals, eventually formed significant surface microhardness (SMH) recovering.

Key words: remineralization, enamel, hydroxyapatite, amino acid

CLC Number:

R318

LIU Ji-Tao, CHUAN Ding-Ze, YANG Ze-Bin, CHEN Xi-Liang, YAN Ting-Ting, CHEN Qing-Hua. In Vitro Remineralization of Acid-etched Bovine Enamel with Amino Acids/Hydroxyapatite Composite[J]. Journal of Inorganic Materials, 2019, 34(11): 1222-1230.

Figures/Tables 10

Fig. 1 FT-IR spectra of the HAP and AA/HAP composite

Fig. 2 XRD patterns of the HAP and AA/HAP composite

Fig. 3 TEM images of the HAP (a1) and AA/HAP (b1); HRTEM of the HAP (a2) and AA/HAP (b2) with inserts showing their corresponding FTT images

Fig. 4 CCK-8 assay of the HAP and AA/HAP at different concentrations

Fig. 5 Ca2+ concentration in the supernatant of remineralization solution

Fig. 6 Surface and cross-section FESEM images of the enamel: sound enamel (a1) and (a2), acid-etched enamel (b1) and (b2) with insert in each image showing corresponding enlarged view

Fig. 7 Surface and cross-section FESEM images of the enamel: blank group (a1, a2), HAP (b1, b2), and AA/HAP (c1, c2) with insert in each image showing corresponding to its enlarged view

Sample	Elemental composition/at%			Ca/P ratio
Sample	O	P	Ca	Ca/P ratio
Polished enamel	19.86	17.97	29.04	1.62
Acid-etched enamel	25.95	19.34	28.59	1.48
Blank group	14.07	17.59	27.85	1.58
HAP group	19.63	16.05	26.20	1.63
AA/HAP group	40.61	17.87	29.49	1.65

Fig. 8 XRD patterns of the enamel surface: sound enamel (a); acid-etched enamel (b); blank group (c); HAP group (d) and AA/HAP group (e)

Fig. 9 Comparison of the SMH before demineralization, after demineralization and after remineralization

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