Bone‐supportive behavior of microplasma‐sprayed CaP‐coated implants: mechanical and histological outcome in the goat

Abstract

New microplasma spray (MPS) equipment to deposit calcium phosphate (CaP) ceramic coatings onto titanium substrates has been developed. With this apparatus, it is possible to spray fine particles, as well as to apply textured hydroxylapatite coatings onto titanium surfaces. Moreover, due to the low heat power of the microplasma jet, overheating of the powder particles as well as excessive local overheating of the substrate is reduced. Furthermore, because of the small laminar plasma jet, it is possible to achieve high spray efficiency in the case of spraying of dental implants. Additionally, the low level of noise (25-50 dB) and hardly any dust makes it possible to operate the MSE under normal workroom conditions. The aim of this study was to examine the biological properties of different MPS - CaP coatings on titanium implants when inserted into the femoral condyle of goats. For histomorphometrical evaluation as well as mechanical testing, 48 screw-type titanium implants were inserted into the femoral condyles of 12 goats each. The implants were either coated with a conventionally plasma-sprayed CaP ceramic, MPS CaP ceramic, or acid-etched without an additional CaP coating. Six and 12 weeks after implantation, the animals were sacrificed and bone-to-implant contact, amount of bone, as well as mechanical bone fixation were evaluated. For bone-to-implant contact no statistically significant difference was found between the different CaP coatings. However, statistically significant differences were found between non-coated, acid-etched titanium implants and CaP-coated implants after 6 and 12 weeks of healing. The bone values were not statistically significantly different between the different CaP coatings at 6 and 12 weeks. Furthermore, CaP ceramic-coated implants showed statistically significantly higher torque values compared with the non-coated implants after 6 and at 12 weeks of healing. No significant differences existed between the various types of CaP coatings. On the basis of our observations, we conclude that conventionally plasma-sprayed CaP ceramic-coated implants, as well as MPS-coated implants have a comparable effect on adjacent bone response.