title: Impacted teeth in the maxilla: usefulness of 3D Dental-CT for preoperative evaluation.
abstract: OBJECTIVE
  To compare the shapes of roots of impacted teeth shown in three-dimensional computed tomographic images (3D Dental-computed tomography (CT) images) and plain radiographs and to determine whether 3D Dental-CT images are useful for examination before performing an operation for extraction of a maxillary impacted tooth.
  
  
  METHODS
  Images obtained from patients who had impacted teeth in the maxilla, including impacted mesial supernumerary teeth in 13 patients, impacted incisors in two patients, impacted canines in 11 patients, impacted premolars in four patients and impacted molars in three patients, were used in this study. In all patients, plain radiographs and 3D Dental-CT images were retrospectively reviewed by an oral radiologist for evidence of root dilaceration before operations to extract the impacted teeth were performed. The findings in the images were compared with intraoperative findings in all cases.
  
  
  RESULTS
  The mean specificity and sensitivity of plain radiographs were 95 and 8%, respectively, while those of 3D Dental-CT images were 100 and 77%, respectively. There was a statistically significant (P<0.01) difference between the depiction capabilities of plain radiographs and 3D Dental-CT images with regard to dilacerations of roots of impacted teeth.
  
  
  CONCLUSIONS
  CT may enable radiologists to make a quick and accurate diagnosis of tooth impaction. 3D Dental-CT images are useful for determining the root shape of an impacted tooth in the maxilla.
authors.affiliation: Department of Dental Radiology, Dental Hospital, Hokkaido University, Kita-13, Nishi-6, Kita-ku, Sapporo 060-8586, Japan. tsuyo@den.hokudai.ac.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sawamura
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Minowa
authors.forename: Motoyasu
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging; D011861:Radiography, Dental / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014095:Tooth, Impacted / Q000000981:diagnostic imaging*