Objective: Tooth surface undergoes continuous remineralization and demineralization. The aim of this study was to compare the effect of Caseinphosphopeptide-amorphous calcium phosphate (CPPACP) paste and Fluoride gel on the microhardness of demineralized enamel lesions.Methods: Frothy eight specimens of premolar teeth were chosen and randomly divided to 4 groups of 12. After the initial measurement of micro-hardness the specimens were immersed in demineralizing solution for 4 day and then the measurements were recorded again. Two groups (GL and G3) were treated with CPP-ACP and Fluoride gel respectively according to manufacturer’s instruction. Two other groups (G2 and G4) were treated with CPP-ACP and fluoride gel every week for three months. After the treatments all specimens were taken into PH-cycling and the microhardness for each one were measured again. For data analysis, the Repeated Measures ANOVA test and the LSD tests were performed. In each group the percentage of micro-hardness recovery was measured.Results: Repeated Measures ANOVA and LED Test showed that the mean value of hardness was significantly decreased after demineralization in all groups (p=0.01). There was no significant difference in mean hardness value in groups (GL, G3) after treatment (p=0.1, p=0.12) In groups (G2, G4) the mean hardness value were significantly increased (p<0.0001, p=0.1). It is noticeable that the CPP-ACP was significantly more efficient than the fluoride gel.Conclusion: CPP-APC paste and fluoride gel both increase the micro-hardness of enamel when administrated for long time and repeated application.

Background and Aim: Dental caries is one of the most common childhood diseases worldwide. The implementation of strategies that facilitate the prevention of early dental caries and interrupt its progression has been recently advocated. It has been reported that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) derived from casein reduces tooth demineralization and enhances the remineralization process. The aim of this in-vitro study was to assess the efficacy of two types of CPPACP paste in calcium uptake by enamel surfaces. Materials and methods: Forty premolars were longitudinally dissected into experimental and control halves, and were coated with nail varnish, except for an enamel window of 4×4 mm. The samples were subjected to cycling in a demineralizing solution and were divided into two groups of GC Tooth Mousse CPP-ACP paste and Misswake CPP-ACP paste. The calcium contents of each half were examined using the acid etch enamel biopsy technique and were measured by atomic absorption. The values were statistically analyzed using Kolmogorov-Smirnov test and one-way analysis of variance (ANOVA). Results: The enamel surfaces treated with the pastes exhibited higher calcium contents compared to the controls. There was a significant difference between GC Tooth Mousse CPP-ACP paste and Misswake CPP-ACP paste in terms of calcium uptake; a higher calcium uptake was witnessed with GC Tooth Mousse CPP-ACP paste than with Misswake CPP-ACP paste (P<0. 05). Conclusion: Misswake CPP-ACP paste presented some protective potentials; however, the samples treated with GC Tooth Mousse CPP-ACP paste were better able to uptake calcium. These pastes could be considered as effective means for the prevention of dental caries in susceptible patients.