title: A mechanical investigation of fluorapatite, magnesiumwhitlockite, and hydroxylapatite plasma-sprayed coatings in goats.
abstract: Ceramic coatings of fluorapatite (FA), magnesiumwhitlockite (MW), and hydroxylapatite (HA), and noncoated Ti-6Al-4V alloy (Ti) implants were evaluated before and after implantation in an animal study. Cylindrical plugs were coated by plasma-spraying with FA, MW, and HA. X-ray-diffraction patterns showed for FA and HA a crystalline and for MW an amorphous-crystalline coating structure. The plugs were implanted into the right femora and left humeri of 16 adult goats. Follow-up periods were 12 and 25 weeks. The in vivo results were evaluated using push-out tests and scanning electron microscopy. There were significant differences in push-out strengths between femur and humerus. The FA and HA implants showed significantly higher push-out strengths than the MW and Ti alloy implants, especially for the 12 week follow-up period. Furthermore, at 12 weeks, MW showed significantly lower push-out strengths than Ti alloy. SEM-investigation of the interfaces revealed that FA did not degrade while both MW and HA showed extensive degradation at 12 and 25 weeks. In addition, the interface after push-out testing showed for the MW, HA, and Ti alloy implants to be fractured at the implant-tissue interface and for the FA to be fractured at the coating-titanium interface.
authors.affiliation: Department of Biomaterials, School of Medicine, University of Leiden, The Netherlands.
authors.forename: W J
authors.initials: WJ
authors.lastname: Dhert
authors.forename: C P
authors.initials: CP
authors.lastname: Klein
authors.forename: J G
authors.initials: JG
authors.lastname: Wolke
authors.forename: E A
authors.initials: EA
authors.lastname: van der Velde
authors.forename: K
authors.initials: K
authors.lastname: de Groot
authors.forename: P M
authors.initials: PM
authors.lastname: Rozing
mesh_terms: D000818:Animals; D001031:Apatites; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000502:physiology*; D002130:Calcium Phosphates; D017886:Durapatite; D005260:Female; D005269:Femur / Q000502:physiology; D006041:Goats; D006811:Humerus / Q000502:physiology; D006882:Hydroxyapatites; D008855:Microscopy, Electron, Scanning; D019736:Prostheses and Implants; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D001672:Biocompatible Materials; D002130:Calcium Phosphates; D006882:Hydroxyapatites; C021767:whitlockite; D017886:Durapatite; C025105:fluorapatite