| Objective:A simple, rapid and environmental friendly method was used to synthesize bio-analog apatites. The influences of ultrasonic time, ultrasonic power or bath temperature on the crystallite features, composition and micro-appearances of the synthesized apatite powders were analyzed by multiple technologies. In addition, a surfactant was employed to modify the synthesized powders and then assembled on the enamel surface in vitro, so as to provider a novel method for rapid preparation of enamel coatings.Method:Na2HPO4, Ca(NO3)2, NaOH and NaF were used as the sources of Phosphate, Calcium, Hydroxyl and Fluoride. Samples depending on ultrasonic time, ultrasonic power and ultrasonic bath temperature were synthesized respectively. X-ray Diffraction (XRD), Fourier-transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were employed to analysis the relevant features of corresponding samples, such as crystallite features, composition and micro-appearances.In the second part, synthesized powders by ultrasonic irradiation were modified by SDS and then dropped on the enamel surfaces, to produce enamel coatings in vitro. In order to analyze the outcome of modification and preparation, FTIR and SEM were separately employed.Result:①A monophase of apatite was obtained by ultrasonic process. The synthesized apatite powders were similar to bio-apatite in terms of crystal dimension, crystallinity, lattice disorder, content of hydroxyl and carbonate groups.②Under longer process time or higher ultrasonic power, the obtained powders were comprised by smaller crystallites. With the increase of bath temperature, the average crystallite sizes of the synthesized powders were increased simultaneously.③In the suspension containing Ca(NO3)2, Na2HPO4, and NaOH, aggregates consists of apatite crystals were produced. Increase of the ultrasonic time and power as well as the bath temperature would improve the synthesis efficiency, i.e. decreases of the content of HPO4- in the powders.④F- was successfully introduced into the crystal lattice by adding NaF to the suspension of Ca(NO3)2, Na2HPO4, and NaOH.⑤Modification of the synthesized powders by a surfactant, SDS, would make it easy and rapid to prepare enamel coatings with relatively much stronger binding forces to the enamel substrate in vitro.Conclusion:Exposure of the suspension under ultrasonic irradiation would produce apatite powders with good dispensability and small dimension. Increase of ultrasonic time or power would cause grain size refinement, yet raising bath temperature inclined to produce crystal grains with larger sizes.The enamel coatings prepared by SDS-modified apatite particles is not yet perfect in the structure, but the fluoride containing bio-analog apatite as well as the SDS would contribute to make the coatings anti-carious and remineralization inductive. The exact properties and mechanism of the coatings on anti-carious features and remineralizaiton inductivities are still need further studies.
|
PDF Full Text Request