title: Low temperature method for the production of calcium phosphate fillers.
abstract: BACKGROUND
  Calcium phosphate manufactured samples, prepared with hydroxyapatite, are used as either spacers or fillers in orthopedic surgery, but these implants have never been used under conditions of mechanical stress. Similar conditions also apply with cements. Many authors have postulated that cements are a useful substitute material when implanted in vivo. The aim of this research is to develop a low cristalline material similar to bone in porosity and cristallinity.
  
  
  METHODS
  Commercial hydroxyapatite (HAp) and monetite (M) powders are mixed with water and compacted to produce cylindrical samples. The material is processed at a temperature of 37-120 degrees C in saturated steam to obtain samples that are osteoconductive. The samples are studied by X-ray powder diffraction (XRD), Vickers hardness test (HV), scanning electron microscopy (SEM), and porosity evaluation.
  
  
  RESULTS
  The X-ray diffractions of powders from the samples show patterns typical of HAp and M powders. After thermal treatment, no new crystal phase is formed and no increase of the relative intensity of the peaks is obtained. Vicker hardness data do not show any relationship with treatment temperature. The total porosity decreases by 50-60% according to the specific thermal treatment. Scanning electron microscopy of the surfaces of the samples with either HAp 80%-M 20% (c) or Hap 50%-M 50% (f), show cohesion of the powder grains.
  
  
  CONCLUSIONS
  The dissolution-reprecipitation process is more intesive in manufactured samples (c) and (f), according to Vickers hardness data. The process occurs in a steam saturated environment between 37 degrees and 120 degrees C. (c) (f) manufactured samples show pore dimension distributions useful to cellular repopulation in living tissues.
authors.affiliation: Department of Cell Biology, University of Calabria, Italy. calafiori@unical.it
authors.forename: Anna Rita
authors.initials: AR
authors.lastname: Calafiori
authors.forename: Marcello
authors.initials: M
authors.lastname: Marotta
authors.forename: Alfonso
authors.initials: A
authors.lastname: Nastro
authors.forename: Guglielmo
authors.initials: G
authors.lastname: Martino
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D002417:Cattle; D017886:Durapatite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011208:Powders; D012995:Solubility; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D011208:Powders; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite