title: Effects of calcium phosphate composition in sputter coatings on in vitro and in vivo performance.
abstract: Calcium phosphate (CaP) ceramic coatings have been used to enhance the biocompatibility and osteoconductive properties of metallic implants. The chemical composition of these ceramic coatings is an important parameter, which can influence the final bone performance of the implant. In this study, the effect of phase composition of CaP-sputtered coatings was investigated on in vitro dissolution behavior and in vivo bone response. Coatings were prepared by a radio frequency (RF) magnetron sputtering technique; three types of CaP target materials were used to obtain coatings with different stoichiometry and calcium to phosphate ratios (hydroxyapatite (HA), α-tricalciumphosphate (α-TCP), and tetracalciumphosphate (TTCP)) were compared with non-coated titanium controls. The applied ceramic coatings were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and inductively coupled plasma optical emission spectroscopy. The in vitro dissolution/precipitation of the CaP coatings was evaluated using immersion tests in simulated body fluid (SBF). To mimic the in vivo situation, identical CaP coatings were also evaluated in a femoral condyle rabbit model. TCPH and TTCPH showed morphological changes during 4-week immersion in SBF. The results of bone implant contact (BIC) and peri-implant bone volume (BV) showed a similar response for all experimental coatings. An apparent increase in tartrate resistant acid phosphatase (TRAP) positive staining was observed in the peri-implant region with decreasing coating stability. In conclusion, the experimental groups showed different coating properties when tested in vitro and an apparent increase in bone remodeling with increasing coating dissolution in vivo.
authors.affiliation: Department of Biomaterials, Radboudumc, PO Box 9101, 6500, HB, Nijmegen, The Netherlands.
authors.forename: Eva R
authors.initials: ER
authors.lastname: Urquia Edreira
authors.forename: Joop G C
authors.initials: JG
authors.lastname: Wolke
authors.forename: Abdullah AlFarraj
authors.initials: AA
authors.lastname: Aldosari
authors.forename: Sulieman S
authors.initials: SS
authors.lastname: Al-Johany
authors.forename: Sukumaran
authors.initials: S
authors.lastname: Anil
authors.forename: John A
authors.initials: JA
authors.lastname: Jansen
authors.forename: Jeroen J J P
authors.initials: JJ
authors.lastname: van den Beucken
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction; D055114:X-Ray Microtomography
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C020243:calcium phosphate
keywords: Ca/P ratio; RF magnetron sputtering; bone healing; calcium phosphate coatings; simulated body fluid (SBF)