Remineralization Potential of Casein Phosphopeptide-Amorphous Calcium Phosphate---- Confocal Microscopy Study

Objectives: To determine if enamel samples treated with casein phosphopeptide-amorphous calcium phosphate(CPP-ACP) containing paste can resist acidic challenge in vitro when measured with confocal microscopy. Methods: Twenty extracted human third molars were sectioned into buccal and lingual halves and divided into three treatment groups (N=10): CPP-ACP Paste only; CPP-ACP and fluoridated toothpaste; CPP-ACP and ACP-containing toothpaste, and a control group with no treatment. The tooth samples with a 2x2 window were subjected to cycling in a demineralizing solution for 8 hrs(pH=4.46) and a remineralizing solution for 15 hrs(pH=7.00), with daily treatments rendered between cycles for 14 days. Tooth sections were stained with Rhodamine B and the artificial lesions were examined using confocal microscopy. Lesion depth, lesion area, fluorescence and total fluorescence were measured. Results were analyzed using ANOVA and Tukey-Kramer analyses (p=0.05). Results: No significant differences were found among the groups for mean lesion depth, lesion area or total fluorescence (p=0.07). There was; however, a definite trend showing reduction in lesion depth,lesion area and total fluorescence in the treatment groups. Lesion depth reduction was: 26.9% for CPP-ACP Paste only; 30.6% for CPP-ACP Paste/fluoridated toothpaste; and 38.3% for CPP-ACP Paste/ACP toothpaste compared to control. Lesion area reduction was: 13.3% for CPP-ACP Paste only; 18.9% for CPP-ACP Paste/fluoridated toothpaste; and 27.5% for CPP-ACP Paste/ACP toothpaste. Although not statistically significant, there was a decrease in fluroescence value in groups treated with CPP-ACP paste compared to the control. The fluorescence value did not appear to correlate with lesion depth, lesion area or total fluorescence. Conclusions: These results suggest that the use of CPP-ACP Paste alone, or in conjunction with commercially available products such as amorphous calcium phosphate containing toothpaste or fluoridated toothpaste has the potential of reducing lesion size and depth, and improving remineralization of enamel in an acidic challenging environment.