title: Performance of calcium deficient hydroxyapatite-polyglycolic acid composites: an in vitro study.
abstract: The strategic incorporation of bioresorbable polymeric additives to calcium-deficient hydroxyapatite cement may provide short-term structural reinforcement and modify the modulus to closer match bone. The longer-term resorption properties may also be improved, creating pathways for bone in-growth. The aim of this study was to investigate the resorption process of a calcium phosphate cement system containing either in polyglycolic acid tri-methylene carbonate particles or polyglycolic acid fibres. This was achieved by in vitro aging in physiological conditions (phosphate buffered solution at 37 degrees C) over 12 weeks. The unreinforced CPC exhibited an increase in compressive strength at 12 weeks, however catastrophic failure was observed above a critical loading. The fracture behaviour of cement was improved by the incorporation of PGA fibres; the cement retained its cohesive structure after critical loading. Gravimetric analysis and scanning electron microscopy showed a large proportion of the fibres had resorbed after 12 weeks allowing for the increased cement porosity, which could facilitate cell infiltration and faster integration of natural bone. Incorporating the particulate additives in the cement did not provide any mechanism for mechanical property augmentation or did not demonstrate any appreciable level of resorption after 12 weeks.
authors.affiliation: School of Mechanical and Aerospace Engineering, Queen's University of Belfast, Belfast, UK. n.dunne@qub.ac.uk
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dunne
authors.forename: Valerie
authors.initials: V
authors.lastname: Jack
authors.forename: Rochelle
authors.initials: R
authors.lastname: O'Hara
authors.forename: David
authors.initials: D
authors.lastname: Farrar
authors.forename: Fraser
authors.initials: F
authors.lastname: Buchanan
mesh_terms: D001843:Bone Cements / Q000737:chemistry; D018786:Bone Substitutes / Q000737:chemistry; D002118:Calcium / Q000494:pharmacology*; D019245:Compressive Strength / Q000187:drug effects; D006882:Hydroxyapatites / Q000737:chemistry*; D066298:In Vitro Techniques; D008422:Materials Testing; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D016062:Porosity; D016474:Weight-Bearing / Q000502:physiology; D014961:X-Ray Diffraction
chemical_list: D001843:Bone Cements; D018786:Bone Substitutes; D006882:Hydroxyapatites; D011100:Polyglycolic Acid; D002118:Calcium