title: The effect of crystallization of bioactive bioglass 45S5 on apatite formation and degradation.
abstract: OBJECTIVE
  Amorphous bioglass 45S5 has been used for many years as bone substitute material. Bioactive glasses are also suitable as coating materials for implants in order to improve the bone ongrowth behavior. We hypothesize that both the apatite formation on the surface and the chemical stability can be improved by crystallization of the bioglass.
  
  
  METHODS
  Synthesized amorphous bioglass 45S5 specimens as well as samples which were crystallized at 1000 °C were stored in simulated body fluid for 1, 7, and 14 days. The respective apatite formation was gravimetrically determined and characterized by SEM and XRD analysis. Moreover, the degradation behavior was studied after storage in distilled water.
  
  
  RESULTS
  The weight of the crystallized samples decreased 6.3% less than that of the amorphous samples. Calcium silica and calcium carbonate layers were found on amorphous bioglass after 7 and 14 days. However, apatite formation was observed only on the crystallized 45S5 samples after storage.
  
  
  CONCLUSIONS
  We conclude that the chemical resistance can be improved and, in parallel, a pronounced apatite formation on the surface of 45S5 can be obtained by controlled crystallization of the material for the particular test setup. Therefore, crystallized bioactive glasses should be considered to be promising coating material for dental implants.
authors.affiliation: Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital, Pauwelsstrasse 30, 52074 Aachen, Germany.
authors.forename: Manja
authors.initials: M
authors.lastname: Plewinski
authors.forename: Karolina
authors.initials: K
authors.lastname: Schickle
authors.forename: Markus
authors.initials: M
authors.lastname: Lindner
authors.forename: Armin
authors.initials: A
authors.lastname: Kirsten
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: Horst
authors.initials: H
authors.lastname: Fischer
mesh_terms: D001031:Apatites / Q000138:chemical synthesis*; D001826:Body Fluids; D002152:Calorimetry, Differential Scanning; D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization; D005898:Glass / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning
chemical_list: D001031:Apatites; C425330:bioactive glass 45S5
keywords: Amorphous bioglass 45S5; Apatite formation; Crystallized 45S5; Simulated body fluid