OBJECTIVETo investigate the effect of the complex of casein phosphopeptide and amorphous calcium phosphate (CPP-ACP) on the demineralization and remineralization of dental enamel in vitro.

METHODSPremolars extracted from patients receiving orthodontic treatment were cut into two slabs, which were embedded and polished. The slabs were randomly divided into non-acid etching group, acid etching group (immersed in 37.5% phosphoric acid for 2 minutes), experimental group A (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 7 days), experimental group B (immersed in 37.5% Phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 14 days), experimental group C (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 21 days), experimental group D (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 28 days), with 6 slabs in each group. The mineral content was determined by scanning electron microscope.

RESULTSThere was a large amount of mineral deposited on enamel surface in experimental group A, B, C, D. The calcium content of experimental group D was higher than those of other 3 experimental groups. The calcium content of experimental group A, B, C, D (66.53 ± 0.63, 67.00 ± 0.49, 67.07 ± 0.24, 67.18 ± 0.50) was higher than that of acid etching group (65.74 ± 0.68) (P < 0.05). There was no significant difference of the calcium content among experimental group A, B, C, D (P > 0.05).

CONCLUSIONSCPP-ACP can reduce enamel demineralization and promote remineralization in vitro.