Quantitative Analysis of Affinity Parameters Between Synthetic Hydroxyapatite and Enamel

Objectives: Particulate synthetic hydroxapatite (HAP) is rapidly gaining importance as a biomimetic agent in oral care products. The prerequisite for an adequate effect of the treatment is an efficient attachment of the HAP particles to the tooth substance. However, quantitative data about the interaction and affinity parameters involved are scarce.
Methods: We use an in-vitro approach with standardized bovine tooth enamel surfaces as model system to investigate the correlation between HAP concentration and particle size and attachment efficiency based on scanning electron microscopy images.
Results: Our results show that for pure mineral-mineral interaction the attachment efficiency increases with particle concentration. However, only a fraction of the particles within the size distribution of the HAP-powder studied can adhere under the tested conditions.
Conclusions: Based on the characteristic parameters obtained, concentration and particle size distribution can be tailored to optimize the efficiency of hydroxyapatite-based oral care formulations.