title: Determination of the mesio-distal tooth width via 3D imaging techniques with and without ionizing radiation: CBCT, MSCT, and µCT versus MRI.
abstract: The purpose of this study was to estimate the feasibility and accuracy of mesio-distal width measurements with magnetic resonance imaging (MRI) in comparison to conventional 3D imaging techniques [multi-slice CT (MSCT), cone-beam CT (CBCT), and µCT]. The measured values of the tooth widths were compared to each other to estimate the amount of radiation necessary to enable orthodontic diagnostics.
  
  
  
  Two pig skulls were measured with MSCT, CBCT, µCT, and MRI. Three different judges were asked to determine the mesio-distal tooth width of 14 teeth in 2D tomographic images and in 3D segmented images via a virtual ruler in every imaging dataset.
  
  
  
  Approximately 19% (27/140) of all test points in 2D tomographic slice images and 12% (17/140) of the test points in 3D segmented images showed a significant difference (P ≤ 0.05). The largest significant difference was 1.6mm (P < 0.001). There were fewer significant differences in the measurement of the tooth germs than in erupted teeth.
  
  
  
  Measurement of tooth width by MRI seems to be clinically equivalent to the conventional techniques (CBCT and MSCT). Tooth germs are better illustrated than erupted teeth on MRI. Three-dimensional segmented images offer only a slight advantage over 2D tomographic slice images. MRI, which avoids radiation, is particularly appealing in adolescents if these data can be corroborated in further studies.
authors.affiliation: Department of Orthodontics and Orofacial Orthopaedics, Universitätsklinikum Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Detterbeck
authors.affiliation: Department of Orthodontics and Orofacial Orthopaedics, Universitätsklinikum Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hofmeister
authors.affiliation: MRB Research Center for Magnetic-Resonance-Bavaria, Würzburg, Germany.|Fraunhofer Development Center X-Ray Technology EZRT, A Division of Fraunhofer Institute for Integrated Circuits IIS, Department Magnetic Resonance and X-Ray Imaging, Würzburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Haddad
authors.affiliation: MRB Research Center for Magnetic-Resonance-Bavaria, Würzburg, Germany.|Fraunhofer Development Center X-Ray Technology EZRT, A Division of Fraunhofer Institute for Integrated Circuits IIS, Department Magnetic Resonance and X-Ray Imaging, Würzburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weber
authors.affiliation: Institute of Medical Biometrics, Informatics and Epidemiology, University of Bonn, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Fraunhofer Institute for Integrated Circuits, Project Group NanoCT Systems, Würzburg, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Hölzing
authors.affiliation: Fraunhofer Institute for Integrated Circuits, Project Group NanoCT Systems, Würzburg, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Zabler
authors.affiliation: Department of Orthodontics and Orofacial Orthopaedics, Universitätsklinikum Erlangen, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hofmann
authors.affiliation: MRB Research Center for Magnetic-Resonance-Bavaria, Würzburg, Germany.|Fraunhofer Development Center X-Ray Technology EZRT, A Division of Fraunhofer Institute for Integrated Circuits IIS, Department Magnetic Resonance and X-Ray Imaging, Würzburg, Germany.
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Hiller
authors.affiliation: MRB Research Center for Magnetic-Resonance-Bavaria, Würzburg, Germany.|Fraunhofer Development Center X-Ray Technology EZRT, A Division of Fraunhofer Institute for Integrated Circuits IIS, Department Magnetic Resonance and X-Ray Imaging, Würzburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Jakob
authors.affiliation: Fraunhofer Institute for Integrated Circuits, Project Group NanoCT Systems, Würzburg, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Engel
authors.affiliation: Fraunhofer Institute for Integrated Circuits, Application Center for CT in Metrology, Deggendorf, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Hiller
authors.affiliation: Department of Orthodontics and Orofacial Orthopaedics, Universitätsklinikum Erlangen, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Hirschfelder
mesh_terms: D059925:Anatomic Landmarks; D000818:Animals; D054893:Cone-Beam Computed Tomography / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007568:Jaw / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging / Q000379:methods; D015588:Observer Variation; D009811:Odontometry / Q000379:methods*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D034421:Sus scrofa; D014057:Tomography, X-Ray Computed / Q000379:methods; D014070:Tooth / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014083:Tooth Germ / Q000033:anatomy & histology / Q000000981:diagnostic imaging