title: Extended CT scale overcomes restoration caused streak artifacts for dental identification in CT--3D color encoded automatic discrimination of dental restorations.
abstract: OBJECTIVE
  Besides DNA, dental radiographs play a major role in the identification of victims in mass casualties or in corpses with major postmortem alterations. Computed tomography (CT) is increasingly applied in forensic investigations and is used to scan the dentition of deceased persons within minutes. We investigated different restoration materials concerning their radiopacity in CT for dental identification purposes.
  
  
  METHODS
  Extracted teeth with different filling materials (composite, amalgam, ceramic, temporary fillings) were CT scanned. Radiopacities of the filling materials were analyzed in extended CT scale images.
  
  
  RESULTS
  Radiopacity values ranged from 6000-8500HU (temporary fillings), 4500-17000HU (composite fillings) and >30710HU (Amalgam and Gold). The values were used to define presets for a 3D colored volume rendering software.
  
  
  CONCLUSIONS
  The effects of filling material caused streak artifacts could be distinctively reduced for the assessment of the dental status and a postprocessing algorithm was introduced that allows for 3D color encoded visualization and discrimination of different dental restorations based on postmortem CT data.
authors.affiliation: Institute of Forensic Medicine, University of Bern, and Department of Diagnostic Radiology, Lindenhofspital, Bremgartenstrasse 117, 3001 Bern, Switzerland. christian.jackowski@irm.unibe.ch
authors.forename: C
authors.initials: C
authors.lastname: Jackowski
authors.forename: A
authors.initials: A
authors.lastname: Lussi
authors.forename: M
authors.initials: M
authors.lastname: Classens
authors.forename: T
authors.initials: T
authors.lastname: Kilchoer
authors.forename: S
authors.initials: S
authors.lastname: Bolliger
authors.forename: E
authors.initials: E
authors.lastname: Aghayev
authors.forename: A
authors.initials: A
authors.lastname: Criste
authors.forename: R
authors.initials: R
authors.lastname: Dirnhofer
authors.forename: M J
authors.initials: MJ
authors.lastname: Thali
mesh_terms: D000180:Acrylic Resins; D000465:Algorithms; D016477:Artifacts; D003188:Composite Resins; D003442:Crowns; D003723:Dental Amalgam; D003793:Dental Restoration, Permanent; D003794:Dental Restoration, Temporary; D005553:Forensic Dentistry; D006801:Humans; D021621:Imaging, Three-Dimensional; D011140:Polyurethanes; D011861:Radiography, Dental; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D011140:Polyurethanes; D003723:Dental Amalgam