Golden apple snail (Pomacea canaliculata L.) Shell as a Biogenic Calcium Source in a Melastoma Malabathricum l.-Enriched Dentifrice: Concentration-Dependent Remineralization Kinetics, Enamel Microhardness Recovery and Anticariogenic Activity

Abstract

Background: Dentine hypersensitivity is associated with an imbalance between enamel demineralization and remineralization, resulting in dentinal tubule exposure and stimulus-induced pain. The shell of the golden apple snail (Pomacea canaliculata L.), an invasive rice pest and abundant agricultural waste in Southeast Asia, is a potential source of biogenic calcium carbonate for sustainable remineralizing dentifrices. Melastoma malabathricum L. fruit (senduduk) provides bioactive phytochemicals with antibacterial potential.
Objective: To determine the effect of P. canaliculata shell concentration on the magnitude, kinetics, and durability of enamel remineralization and identify the optimal dentifrice formulation.
Methods: Four dentifrices containing 5%, 10%, 15%, and 20% (w/w) P. canaliculata shell powder with a fixed M. malabathricum fruit fraction were compared with a commercial sodium fluoride/potassium nitrate dentifrice. One hundred permanent human canines were demineralized at pH 3 for 72 h and allocated to five groups, each subdivided into 90-, 180-, 270-, and 360-min immersion periods (n = 5). Outcomes included Vickers surface microhardness, artificial salivary calcium concentration, antibacterial activity against Streptococcus mutans and Escherichia coli, scanning electron microscopy, pH, homogeneity, and compliance with SNI 12-3524-1995.
Results: All formulations were homogeneous, pH-neutral (pH 7), free of E. coli, and compliant with SNI requirements. Microhardness differed significantly among groups at all time points (p < 0.001; η² = 0.70–0.96). Peak hardness ranged from 306.50 to 341.83 HV, representing a 132–159% increase from baseline. The 5% formulation reached peak hardness at 180 min and showed the strongest early remineralization, whereas higher concentrations required longer exposure. At 90 min, hardness was inversely correlated with shell concentration (r = −0.947). The 5% formulation achieved hardness comparable to the commercial control (341.83 vs. 332.00 HV; p = 0.45), but demonstrated superior mineral retention and the greatest integrated mineral gain (48,945 vs. 39,583 HV·min). S. mutans inhibition was strongest with the 5% formulation (16 mm) and declined with increasing shell concentration, whereas no formulation inhibited E. coli. Salivary calcium decreased across all groups, indicating net mineral uptake.
Conclusion: Shell concentration primarily influenced remineralization kinetics and mineral retention rather than ultimate remineralization capacity. The 5% formulation demonstrated the most favorable overall performance, combining control-equivalent peak microhardness, superior mineral retention, and the strongest S. mutans inhibition. P. canaliculata shell combined with M. malabathricum fruit therefore represents a promising locally sourced and circular-bioeconomy-based dentifrice candidate.