title: Cortical bone screw fixation in ionically modified apatite cements.
abstract: Hydroxyapatite cements are used in reconstruction of the face; usually in well-defined cavities where the cement can be stabilized without the need for internal fixation. A hydroxyapatite cement that could enable screw fixation and some loading therefore has considerable potential in maxillofacial reconstruction. It has been demonstrated recently that water demand of calcium phosphate cements can be reduced by ionically modifying the liquid component. This study investigated the capacity of an ionically modified precompacted apatite cement to retain self-tapping cortical bone screws. Screw pullout forces were determined in the direction of the screw long axis and perpendicular to it, using cortical bone and polymethylmethacrylate cement as a control. In bending pullout tests, measured forces to remove screws from ionically modified precompacted cement were insignificantly different from cortical bone. However, pullout forces of bone screws from hydroxyapatite cement decreased with aging time in vitro.
authors.affiliation: Faculty of Dentistry, Strathcona Building, McGill University, 3640 University Street, Montreal, Quebec H3A 2B2, Canada. jake.barralet@mcgill.ca
authors.forename: J E
authors.initials: JE
authors.lastname: Barralet
authors.forename: C O
authors.initials: CO
authors.lastname: Duncan
authors.forename: M S
authors.initials: MS
authors.lastname: Dover
authors.forename: D C
authors.initials: DC
authors.lastname: Bassett
authors.forename: H
authors.initials: H
authors.lastname: Nishikawa
authors.forename: A
authors.initials: A
authors.lastname: Monaghan
authors.forename: U
authors.initials: U
authors.lastname: Gbureck
mesh_terms: D001843:Bone Cements / Q000737:chemistry*; D001863:Bone Screws; D002130:Calcium Phosphates; D004355:Drug Stability; D017886:Durapatite; D005593:Fracture Fixation, Internal; D008422:Materials Testing
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; D017886:Durapatite; C020243:calcium phosphate