title: Generation of mineral density distribution maps from subject-specific models of mandibles - a preliminary study.
abstract: BACKGROUND
  Determination of the mineral content of bone and its distribution by computed tomography (CT) enables one to define the insertion points for prosthetic devices, or determine the degree of healing in cases of fracture or surgical intervention. The use of subject-specific models allows mapping of the spatial structure and the mineral content of the bone graphically and quantitatively.
  
  
  METHODS
  Subject-specific models and mineral density maps from pig jaws were developed using segmentation, transcription tools and finite element analysis software. This study considered six frozen heads from pigs aged 10-12 months, and phantom solutions of K(2) HPO(4) . The predicted bone mass of each jaw was compared with its respective ash mass after incineration.
  
  
  RESULTS
  The tridimensional maps show highest density values at the molar cusp and within the symphysis. The average percentage error relative to the mineral density maps was -18.4%. The radiation dose was reduced by a factor of eight from the recommended maximum without compromising the precision of the models.
  
  
  CONCLUSIONS
  The computed tridimensional mineral density maps illustrate, numerically and graphically, the spatial distribution of the density field within the mandibular bone. These maps could facilitate the location of insertion points or determine the evolution of the mineralization level of a patient's bone tissue.
authors.affiliation: Department of Mechanical and Metallurgical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Alister
authors.forename: Jorge Andrés
authors.initials: JA
authors.lastname: Ramos-Grez
authors.forename: Alex Patricio
authors.initials: AP
authors.lastname: Vargas
mesh_terms: D000818:Animals; D015519:Bone Density; D003198:Computer Simulation; D020342:Finite Element Analysis; D021621:Imaging, Three-Dimensional; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000378:metabolism*; D008953:Models, Anatomic; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted; D013552:Swine; D014057:Tomography, X-Ray Computed