title: Characterization of a new composite PMMA-HA/Brushite bone cement for spinal augmentation.
abstract: Calcium phosphate fillers have been shown to increase cement osteoconductivity, but have caused drawbacks in cement properties. Hydroxyapatite and Brushite were introduced in an acrylic two-solution cement at varying concentrations. Novel composite bone cements were developed and characterized using rheology, injectability, and mechanical tests. It was hypothesized that the ample swelling time allowed by the premixed two-solution cement would enable thorough dispersion of the additives in the solutions, resulting in no detrimental effects after polymerization. The addition of Hydroxyapatite and Brushite both caused an increase in cement viscosity; however, these cements exhibited high shear-thinning, which facilitated injection. In gel point studies, the composite cements showed no detectable change in gel point time compared to an all-acrylic control cement. Hydroxyapatite and Brushite composite cements were observed to have high mechanical strengths even at high loads of calcium phosphate fillers. These cements showed an average compressive strength of 85 MPa and flexural strength of 65 MPa. A calcium phosphate-containing cement exhibiting a combination of high viscosity, pseudoplasticity and high mechanical strength can provide the essential bioactivity factor for osseointegration without sacrificing load-bearing capability.
authors.affiliation: Department of Bioengineering, University of Texas at Dallas, Texas, USA sxa117530@utdallas.edu.
authors.forename: Shant
authors.initials: S
authors.lastname: Aghyarian
authors.affiliation: Department of Bioengineering, University of Texas at Dallas, Texas, USA.
authors.forename: Lucas C
authors.initials: LC
authors.lastname: Rodriguez
authors.affiliation: Department of Bioengineering, University of Texas at Dallas, Texas, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Chari
authors.affiliation: Department of Bioengineering, University of Texas at Dallas, Texas, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bentley
authors.affiliation: Orthopedic Surgery Department, University of North Texas Health Science Center (UNTHSC), Texas, USA Department of Materials Science and Engineering, University of North Texas, Texas, USA.
authors.forename: Victor
authors.initials: V
authors.lastname: Kosmopoulos
authors.affiliation: Scoliosis & Spine Tumor Center, Texas Back Institute, Texas Health Plano Hospital, Texas, USA.
authors.forename: Isador H
authors.initials: IH
authors.lastname: Lieberman
authors.affiliation: Department of Bioengineering, University of Texas at Dallas, Texas, USA.
authors.forename: Danieli C
authors.initials: DC
authors.lastname: Rodrigues
mesh_terms: D001843:Bone Cements / Q000737:chemistry*; D018786:Bone Substitutes; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D019245:Compressive Strength; D017886:Durapatite / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods; D016348:Osseointegration / Q000502:physiology*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D011312:Pressure; D012212:Rheology; D016103:Spinal Fractures; D013131:Spine / Q000737:chemistry*; D013314:Stress, Mechanical; D054854:Vertebroplasty; D014783:Viscosity; D016474:Weight-Bearing
chemical_list: D001843:Bone Cements; D018786:Bone Substitutes; D002130:Calcium Phosphates; D011108:Polymers; D019904:Polymethyl Methacrylate; D017886:Durapatite; C020243:calcium phosphate; C494366:calcium phosphate, dibasic, dihydrate; D002118:Calcium
keywords: Composite bone cement; bone cement; calcium phosphate; poly-methyl methacrylate; spine; vertebral compression fracture; vertebroplasty