ABSTRACT
<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>Premolars 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.</p><p><b>RESULTS</b>There 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).</p><p><b>CONCLUSIONS</b>CPP-ACP can reduce enamel demineralization and promote remineralization in vitro.</p>