RAMAN MICROPROBE INVESTIGATION OF THE CALCIUM-PHOSPHATE PHASES OF 3 COMMERCIALLY AVAILABLE PLASMA-FLAME-SPRAYED HYDROXYAPATITE-COATED DENTAL IMPLANTS

The purpose of the current study was to evaluate the crystallographic properties of three commercially plasma-flame-sprayed hydroxyapatite (HAp) coatings on dental implants. For this purpose a Raman microprobe (MOLE U1000) was used. No preparation of the surfaces was necessary to examine the thin ceramic surface layers. Microspectra (5 mum) and macrospectra (1 00 mum) have been measured and compared to the spectra of crystalline and amorphous HAp as well as to the spectra of tricalciumphosphate. All implants showed spectra that were more like that of the amorphous phase of HAp than any of the other examined reference materials. However, the implant spectra exhibited an extra band that as yet has not been identified. This band is probably indicative of some structure within the sprayed amorphous phase. Such structural effects would result either directly from quenching from the plasma state or by incorporation of titanium into the lattice during plasma treatment.