Influence of preferred orientation on the bioactivity of hydroxyapatite: a potential tooth repair and implant surface coating material

Abstract

Abstract Bioactive hydroxyapatite (HAp) material was synthesized using a simple wet chemical precipitation and heat-treatment method from snail (Achatina achatina) shells and a phosphate-containing solution. According to X-ray diffraction patterns obtained, the heat-treatment caused a crystallographic preferred orientation along the HAp c-axis and thus, affected the material mineralization and bioactivity modeled in vitro using simulated body fluid (SBF) for 7 and 21 days. After 21 days of immersion, calcium and phosphate mineral concentrations in SBF decreased by 66% and 83%, respectively. This corresponded to a transformation from a poor calcium amorphous apatite phase (calcium phosphate) to a resorbing crystalline calcium apatite indicated by scanning electron microscopy micrographs. The material crystallite size (~15 nm), lattice parameters, physicochemical properties, and morphological characteristics were all typical of the human enamel apatite and, therefore, could be considered ideal for use in tooth repairs and implant surface coatings.

Keywords

• bioactivity
• biomaterial
• hydroxyapatite
• snail shell