title: Biomechanical and histomorphometric investigations on two morphologically differing titanium surfaces with and without fluorohydroxyapatite coating: an experimental study in sheep tibiae.
abstract: The influence of fluorohydroxyapatite (FHA) coating and surface roughness of Ti6Al4V implants on bone response was investigated. Uncoated and FHA-coated screws with lower (LR and LR+FHA; Ra: 5.7+/-0.2 microm) and higher (HR and HR+FHA; Ra: 21.8+/-0.9 microm) surface roughness, were inserted into the diaphyses of 8 sheep tibiae. Twelve weeks after implantation, extraction torque and bone-to-implant contact were evaluated. The smoothest surfaces showed an improved extraction torque and significant differences were observed between LR and HR (-24.6%, p<0.0005), LR and HR+FHA (-30.7%, p<0.0005), LR+FHA and HR (-17.4%, p<0.005), and LR+FHA and HR+FHA (-24.0%, p<0.005). The bone-to-implant contact data paralleled the biomechanical data: the smoother the surface, the greater the bone-to-implant contact. Significant (p<0.0005) decreases in bone-to-implant contact were observed between LR+FHA and HR (-24.2%), and between LR+FHA and HR+FHA (-29.2%). The current findings suggest that LR surfaces significantly improve the osteointegration rate of implanted cortical screws independently of the FHA coating.
authors.affiliation: Experimental Surgery Department, Codivilla-Putti Research Institute, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136 Bologna, Italy. milena.fini@ior.it
authors.forename: M
authors.initials: M
authors.lastname: Fini
authors.forename: L
authors.initials: L
authors.lastname: Savarino
authors.forename: N
authors.initials: N
authors.lastname: Nicoli Aldini
authors.forename: L
authors.initials: L
authors.lastname: Martini
authors.forename: G
authors.initials: G
authors.lastname: Giavaresi
authors.forename: G
authors.initials: G
authors.lastname: Rizzi
authors.forename: D
authors.initials: D
authors.lastname: Martini
authors.forename: A
authors.initials: A
authors.lastname: Ruggeri
authors.forename: A
authors.initials: A
authors.lastname: Giunti
authors.forename: R
authors.initials: R
authors.lastname: Giardino
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001863:Bone Screws; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D006882:Hydroxyapatites / Q000494:pharmacology*; D008422:Materials Testing; D016348:Osseointegration; D019736:Prostheses and Implants; D012756:Sheep; D013314:Stress, Mechanical; D013499:Surface Properties; D013977:Tibia / Q000473:pathology*; D014025:Titanium / Q000378:metabolism*
chemical_list: D001672:Biocompatible Materials; D020099:Coated Materials, Biocompatible; D006882:Hydroxyapatites; C116586:fluorohydroxyapatite; D014025:Titanium