An anhydrous carboxymethyl chitosan/amorphous calcium phosphate nanocomposite toothpaste promotes enamel surface remineralization.

BACKGROUND

Early-stage carious lesions remain amenable to remineralization if appropriately managed. Various remineralizing toothpaste formulations have been developed and commercialized. Although these products have demonstrated certain remineralizing efficacy, each possesses inherent limitations. Carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) nanocomposites have been shown to possess both surface remineralization and antibacterial properties. However, a critical limitation remains: the bioactivity of CMC/ACP nanoparticles diminishes upon prolonged exposure to aqueous environments due to spontaneous crystallization, which precludes their direct incorporation into conventional aqueous toothpaste formulations.

PURPOSE: This study aimed to develop and evaluate a novel anhydrous toothpaste containing Carboxymethyl Chitosan/Amorphous Calcium Phosphate (CMC/ACP) nanoparticles for early caries management.

MATERIALS AND

METHODS

CMC/ACP nanoparticles (Ca/P = 20:12) were synthesized and characterized using TEM, XRD, and TG. The nanoparticles were incorporated into an anhydrous matrix to ensure stability. Antibacterial efficacy against Streptococcus mutans was assessed via CLSM and SEM. surface remineralization of demineralized enamel was evaluated through in vitro and in vivo rat models using SEM, EDS, and XRD. Biosafety was verified via CCK-8 assays and systemic animal toxicity tests.

RESULTS

CMC/ACP nanoparticles were stable in anhydrous matrix for one year with controlled ion release. The toothpaste inhibited S. mutans adhesion/biofilm (p < 0.05). A 2 μm surface remineralized layer formed within 3 days in vitro/vivo. The material showed excellent biocompatibility without oral or systemic toxicity.

CONCLUSION

The CMC/ACP dual-functional toothpaste effectively prevents caries by inhibiting early-stage biofilm formation and promoting robust enamel surface remineralization, offering a promising clinical strategy for daily oral care.

CLINICAL SIGNIFICANCE: As a daily-use toothpaste, the anhydrous CMC/ACP nanocomposite formulation offers improved patient compliance and greater convenience, enabling safe at-home enamel surface remineralization and caries inhibition. It provides a straightforward, noninvasive strategy for preventing early enamel caries and repairing white spot lesions, with strong potential for clinical translation and widespread application in public oral health.