Mineralizing Properties of Calcium Phosphate-Based Treatment for Enamel Surfaces

Objective: The aim of this study is to determine  the efficacy of adding zinc (Zn²⁺) or fluoride (F^-) or both ions to a saturated calcium phosphate solution (sCaP) in providing enamel surfaces that are less susceptible to acid dissolution. 

Method: Extracted human molars were collected, sterilized by autoclaving and sectioned. The enamel sections (n=12) were treated with the following saturated calcium phosphate (sCaP) solutions: (A) containing F^-+ Zn²⁺ ions, (B) containing only F^- ions , (C) containing only Zn²⁺ ions, (D) without Zn²⁺ or F^- ions. Enamel surfaces were characterized using scanning electron microscopy (SEM). The dissolution properties of the enamel surfaces were determined in acidic buffer (0.1M KAc, pH 6, 37⁰C) by monitoring the release of calcium ions with time using inductive coupled plasma (ICP). The effect of pre-treatment with albumin on the dissolution properties was also investigated. Statistical analysis employed ANOVA followed by Tukey’s HSD test.

Result: SEM images showed that greater amount of crystal deposits were observed on enamel surfaces treated with solution A compared to surfaces treated with solutions B, C, or D, with the surface treated with solution D showing the least amount.  All the treated groups showed significant difference in reducing enamel susceptibility to acid dissolution compared to the untreated group. The greatest effect was observed in group treated with solution A, and the least effect in the group treated with solution D. No significant difference in dissolution properties was observed between groups pretreated or not pretreated with albumin.

Conclusion: sCaP solutions containing F^- and Zn²⁺ ions are effective in providing a protective coating against acid dissolution on enamel surfaces. Results of this study suggest that calcium phosphate-based solutions containing these ions may be a  potential strategy for making the enamel surface less susceptible to acid dissolution.