title: [Influence of different mixing fluids on mechanical and micromorphological in vitro qualities of hydroxyapatite cement].
abstract: OBJECTIVE
  In reconstructive craniofacial surgery a new synthetic hydroxyapatite cement has been used in the last few years. Tetra- and dicalcium phosphates react with either slow setting aqua bidest. or with faster setting sodium monophosphate solution to hydroxyapatite. The aim of this study was to investigate the two mixing fluids of hydroxyapatite for resulting micromorphology, pressure strength, and interactions with fibroblasts.
  
  
  METHODS
  Pressure strength tests of hydroxyapatite cement test samples (n=80) were performed after a setting time of 3 and 24 h. The micromorphology of surfaces of the resulting particles was assessed under an electron microscope. In cell cultures L-929 and HEp2 cells were incubated with test samples and cell growth was assessed by light and electron microscopy.
  
  
  RESULTS
  The test samples mixed with sodium monophosphate solution showed statistically significantly higher values of pressure strength. The resulting pressure strength depended on respective mixing fluids, setting time, and pressure of application. In general, test samples mixed with sodium monophosphate solution showed a more load-stable, homogeneous anorganic matrix whereas test samples mixed with aqua bidest. had a porous microarchitecture which was more fragile. In cell culture the porous structure showed disintegration in cell culture medium.
  
  
  CONCLUSIONS
  To what extent the two mixing liquids of hydroxyapatite cement influence the resorption and bony substitution has to be shown in further studies.
authors.affiliation: Abteilung für Mund-, Kiefer- und Gesichtschirurgie, Georg-August-Universität Göttingen, 37075 Göttingen. axel.nitsch@gmx.de
authors.forename: A
authors.initials: A
authors.lastname: Nitsch
authors.forename: A
authors.initials: A
authors.lastname: Patyk
authors.forename: P
authors.initials: P
authors.lastname: Schwartz
authors.forename: H-A
authors.initials: HA
authors.lastname: Merten
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002460:Cell Line; D045744:Cell Line, Tumor; D005079:Excipients; D005347:Fibroblasts; D006801:Humans; D006882:Hydroxyapatites / Q000737:chemistry*; D066298:In Vitro Techniques; D007822:Laryngeal Neoplasms / Q000473:pathology; D008689:Methacrylates; D051379:Mice; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D019647:Oral Surgical Procedures; D010710:Phosphates; D013329:Structure-Activity Relationship
chemical_list: C121036:Aqua-Prep; D005079:Excipients; D006882:Hydroxyapatites; D008689:Methacrylates; D010710:Phosphates; C475044:hydroxyapatite cement; C018279:sodium phosphate