Bovine Cancellous Hydroxyapatite Toothpaste Enhances Enamel Remineralization

Abstract

Background: Hydroxyapatite (HA) is a biomimetic material capable of promoting enamel remineralization and exhibiting antimicrobial properties. Bovine cancellous bone is a promising HA source due to its bioactivity, biocompatibility, and cost-effectiveness. This study evaluated the effects of toothpaste formulations containing varying concentrations of bovine cancellous HA (1%, 3%, and 5%) on enamel remineralization, antimicrobial activity, abrasivity, and biocompatibility.

Methods: Toothpaste formulations were prepared with bovine cancellous HA at 1%, 3%, and 5%, alongside a base formulation and a commercial control. Physical properties (pH, viscosity, homogeneity, stability) and organoleptic characteristics (odour, taste, texture, colour) were assessed. Enamel remineralization was evaluated via Vickers microhardness testing and surface roughness analysis after simulated brushing. Antimicrobial activity was assessed against Staphylococcus aureus and Candida albicans.

Results: All formulations exhibited slightly alkaline pH, stable viscosity, uniform homogeneity, and no phase separation over 30 days. Sensory evaluation indicated that 3% HA toothpaste provided the optimal balance between functionality and acceptability. Brushing with HA toothpaste increased enamel microhardness in a dose-dependent manner, with 3% and 5% HA toothpaste showing superior remineralization (Vickers Hardness Number: 327.6 ± 14.0 and 319.4 ± 19.9, respectively) compared to 1% (226.9 ± 11.1). Surface roughness was minimized with HA incorporation, indicating protective effects against enamel wear. Antimicrobial assays demonstrated concentration-dependent inhibition of S. aureus, with the 5% HA toothpaste (9.1 ± 0.06 mm) comparable to commercial toothpaste (9.4 ± 0.1 mm), whereas inhibition of C. albicans was highest at 1% HA (9.7 ± 1.2 mm).

Conclusion: Bovine cancellous HA toothpaste effectively enhances enamel remineralization, reduces abrasivity, exhibits antimicrobial potential, and demonstrates excellent biocompatibility. The 3% to 5% HA toothpaste provide a balanced combination of efficacy, safety, and user acceptability, supporting their potential for translational applications in preventive oral care.

Keywords: Antimicrobial; Bovine cancellous bone; Enamel remineralization; Hydroxyapatite; Toothpaste.