Development of high-viscosity, two-paste bioactive bone cements.
Self-curing two-paste bone cements have been developed using methacrylate monomers with a view to formulate cements with low polymerization exotherm, low shrinkage, better mechanical properties, and improved adhesion to bone and implant surfaces. The monomers include bis-phenol A glycidyl dimethacrylate (bis-GMA), urethane dimethacrylate (UDMA) and triethylene glycol dimethacrylate (TEGDMA) as a viscosity modifier. Two-paste systems were formulated containing 60% by weight of a bioactive ceramic, hydroxyapatite. A methacroyloxy silane (A174) was used as a coupling agent due to its higher water stability in comparison to other aminosilanes to silanate the hydroxyapatite particles prior to composite formulation. A comparison of the FT-infrared spectrum of hydroxyapatite and silanated hydroxyapatite showed the presence of the carbonyl groups ( approximately 1720 cm(-1)), -C=C-( approximately 1630 cm(-1)) and Si-O- (1300-1250 cm(-1)) which indicated the availability of silane groups on the filler surface. Two methods of mixing were effected to form the bone cement: firstly by mixing in an open bowl and secondly by extruding the two pastes by an auto-mixing tip using a gun to dispense the pastes. Both types of cements yielded low polymerization exotherms with good mechanical properties; however, the lower viscosity of UDMA allowed better extrusion and handling properties. A biologically active apatite layer formed on the bone cement surface within a short period after its immersion in simulated body fluid, demonstrating in vitro bioactivity of the composite. This preliminary data thus suggests that UDMA is a viable alternative to bis-GMA as a polymerizable matrix in the formation of bone cements.
Deb
S
S
Department of Dental Biomaterials, Guy's King's & St. Thomas' Dental Institute, King's College, Floor 17, Guy's Tower, London Bridge, London SE1 2RT, UK. sanjukta.deb@kcl.ac.uk
Aiyathurai
L
L
Roether
J A
JA
Luklinska
Z B
ZB
D040761:Biomimetic Materials / Q000032:analysis / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000032:analysis* / Q000737:chemistry*; D001826:Body Fluids / Q000737:chemistry*; D001843:Bone Cements / Q000032:analysis* / Q000737:chemistry*; D006244:Hardness; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000032:analysis* / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000032:analysis* / Q000737:chemistry*; D013499:Surface Properties; D014783:Viscosity
D001843:Bone Cements; D011109:Polymethacrylic Acids; C080508:poly(triethylene glycol dimethacrylate-1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimethylhexane) copolymer; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate