title: Hydroxyapatite particles maintain peri-implant bone mantle during osseointegration in osteoporotic bone.
abstract: In osteoporotic bones, resorption exceeds formation during the remodelling phase of bone turnover. As a consequence, decreased bone volume and bone contact result in the peri-implant region. This may subsequently lead to loss of fixation. In this study we investigated whether the presence of nonresorbable, osteoconductive hydroxyapatite (HA) particles could help maintain a denser and more functional peri-implant bone structure. Titanium screws were implanted into the proximal tibial metaphysis of four months old, ovariectomized Wistar rats (n=60). In the right tibia, the drill hole was first filled with HA particles, while the left tibia served as a control without HA particles. Histological analysis demonstrated that during the remodelling phase the amount of newly formed bone was significantly higher on the HA over the control side. Micro-CT analysis corroborated the significant changes over time as well as differences in peri-implant bone volume density between treatment and control group. Mechanical tests demonstrated that the pull-out force was greater with HA particles. These results indicate that HA particles are able to induce and maintain for a longer time a denser peri-implant bone mantle in osteoporotic bone, which may have important implications in the prevention of implant migration and cut-outs.
authors.affiliation: AO Research Institute, AO Foundation, Clavadelerstrasse 8, 7270 Davos, Switzerland. andrea.tami@aofoundation.org
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Tami
authors.forename: Melanie M
authors.initials: MM
authors.lastname: Leitner
authors.forename: Michelle G
authors.initials: MG
authors.lastname: Baucke
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Mueller
authors.forename: G Harry
authors.initials: GH
authors.lastname: van Lenthe
authors.forename: Ralph
authors.initials: R
authors.lastname: Müller
authors.forename: Keita
authors.initials: K
authors.lastname: Ito
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology*; D017886:Durapatite / Q000494:pharmacology*; D005260:Female; D020007:Implants, Experimental; D016348:Osseointegration / Q000187:drug effects*; D010012:Osteogenesis / Q000187:drug effects; D010024:Osteoporosis / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography
chemical_list: D017886:Durapatite