Thin film hydroxyapatite as a model dental surface

This paper reports the use of thin film hydroxyapatite (HA) coatings, deposited by RF magnetron sputtering, as a possible model dental surface. Dissolution behavior of the coatings has been monitored by exposure to Phosphate Buffered Saline (PBS) solution for periods of 1 hr, 24 hrs and 7 days and analyzed by FTIR, XPS and AFM. Coatings sputter deposited at 15 mTorr argon gas pressure proved to be the most stable, with post deposition annealing to 500degreesC noted to further enhance the stability of the coating. Micro- and nano-indentation techniques indicate that the HA coatings exhibit hardness values close to that of polished human enamel samples. Wear tests have been conducted in the presence of toothpaste of varying abrasivity and also indicate that the HA coatings perform in a similar manner to the enamel controls.