title: A comparison of a new limited cone beam computed tomography machine for dental use with a multidetector row helical CT machine.
abstract: OBJECTIVE
  We sought to compare a new limited cone beam computed tomography (CT) machine for dental use (3DX) with the multidetector CT machine for image quality and skin doses.
  
  
  METHODS
  Images of the right maxillary central incisor and the left mandibular first molar of an anthropomorphic phantom were taken by both the 3DX and the multidetector CT. A 5-point method was used to evaluate the depiction of cortical and cancellous bone, enamel, dentin, pulp cavity, periodontal ligament space, lamina dura, and overall impressions. Furthermore, the skin doses for both modalities were compared.
  
  
  RESULTS
  The image quality of the 3DX was better than the multidetector CT for all items (P < .01). Moreover, the mean skin doses with the multidetector CT were 458 mSv per examination, whereas the doses with the 3DX were 1.19 mSv per examination.
  
  
  CONCLUSIONS
  These results clearly indicate the superiority of the 3DX in the display of hard tissues in the dental area while substantially decreasing the dose to the patient.
authors.affiliation: Department of Radiology and Division os Advanced Dental Treatment, School of Dentistry and Dental Research Center, Nihon University, Tokyo, Japan. hashimoto-k@dent.nihon-u.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Arai
authors.forename: Kazuo
authors.initials: K
authors.lastname: Iwai
authors.forename: Masao
authors.initials: M
authors.lastname: Araki
authors.forename: Shoji
authors.initials: S
authors.lastname: Kawashima
authors.forename: Masaaki
authors.initials: M
authors.lastname: Terakado
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation; D007180:Incisor / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D015588:Observer Variation; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D019252:Radiography, Dental, Digital / Q000295:instrumentation*; D036542:Tomography, Spiral Computed / Q000295:instrumentation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014963:X-Ray Intensifying Screens