title: Compositional dependence of bioactivity of glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2.
abstract: The bioactivity, i.e., bone-bonding ability, of 26 glasses in the system Na2O-K2O-MgO-CaO-B2O3-P2O5-SiO2 was studied in vivo. This investigation of bioactivity was performed to establish the compositional dependence of bioactivity, and enabled a model to be developed that describes the relation between reactions in vivo and glass composition. Reactions in vivo were investigated by inserting glass implants into rabbit tibia for 8 weeks. The glasses and the surrounding tissue were examined using scanning electron microscopy (SEM), light microscopy, and energy-dispersive X-ray analysis (EDXA). For most of the glasses containing < 59 mol % SiO2, SEM and EDXA showed two distinct layers at the glass surface after implantation, one silica-rich and another containing calcium phosphate. The build-up of these layers in vivo was taken as a sign of bioactivity. The in vivo experiments showed that glasses in the investigated system are bioactive when they contain 14-30 mol % alkali oxides, 14-30 mol % alkaline earth oxides, and < 59 mol % SiO2. Glasses containing potassium and magnesium bonded to bone in a similar way as bioactive glasses developed so far.
authors.affiliation: Department of Chemical Engineering, Abo Akademi University, Abo/Turku, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Brink
authors.forename: T
authors.initials: T
authors.lastname: Turunen
authors.forename: R P
authors.initials: RP
authors.lastname: Happonen
authors.forename: A
authors.initials: A
authors.lastname: Yli-Urpo
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology*; D001843:Bone Cements / Q000737:chemistry / Q000494:pharmacology; D001896:Boron Compounds; D017610:Calcium Compounds; D004577:Electron Probe Microanalysis; D005260:Female; D005898:Glass / Q000737:chemistry*; D020007:Implants, Experimental; D008277:Magnesium Oxide; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D016348:Osseointegration; D010087:Oxides; D017553:Phosphorus Compounds; D017680:Potassium Compounds; D011817:Rabbits; D012822:Silicon Dioxide; D017670:Sodium Compounds; D013977:Tibia / Q000187:drug effects / Q000601:surgery / Q000648:ultrastructure
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D001896:Boron Compounds; D017610:Calcium Compounds; D010087:Oxides; D017553:Phosphorus Compounds; D017680:Potassium Compounds; D017670:Sodium Compounds; C096707:sodium oxide; D008277:Magnesium Oxide; C042168:boron oxide; C012500:phosphorus pentoxide; C068440:potassium oxide; D012822:Silicon Dioxide; C016538:lime