title: Influence of basis images and skull position on evaluation of cortical bone thickness in cone beam computed tomography.
abstract: OBJECTIVE
  The aim of this study was to assess the influence of the number of basis images and the orientation of the skull on the evaluation of cortical alveolar bone in cone beam computed tomography (CBCT).
  
  
  METHODS
  Eleven skulls with a total of 59 anterior teeth were selected. CBCT images were acquired by using 4 protocols, by varying the rotation of the tube-detector arm and the orientation of the skull (protocol 1: 360°/0°; protocol 2: 180°/0°; protocol 3: 180°/90°; protocol 4: 180°/180°). Observers evaluated cortical bone as absent, thin, or thick. Direct observation of the skulls was used as the gold standard. Intra- and interobserver agreement, as well as agreement of scoring between the 3 bone thickness classifications, were calculated by using the κ statistic. The Wilcoxon signed-rank test was used to compare the 4 protocols.
  
  
  RESULTS
  For lingual cortical bone, protocol 1 showed no statistical difference from the gold standard. Higher reliability was found in protocol 3 for absent (κ = 0.80) and thin (κ = 0.47) cortices, whereas for thick cortical bone, protocol 2 was more consistent (κ = 0.60). In buccal cortical bone, protocol 1 obtained the highest agreement for absent cortices (κ = 0.61), whereas protocol 4 was better for thin cortical plates (κ = 0.38) and protocol 2 for thick cortical plates (κ = 0.40).
  
  
  CONCLUSIONS
  No consistent effect of the number of basis images or head orientation for visual detection of alveolar bone was detected, except for lingual cortical bone, for which full rotation scanning showed improved visualization.
authors.affiliation: Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil. Electronic address: Monikellyccn@gmail.com.
authors.forename: Monikelly do Carmo Chagas
authors.initials: MDCC
authors.lastname: Nascimento
authors.affiliation: Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Solange Maria de Almeida
authors.initials: SMA
authors.lastname: Boscolo
authors.affiliation: Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Francisco
authors.initials: F
authors.lastname: Haiter-Neto
authors.affiliation: Pontifical Catholic University of Paraná, Curitiba - Paraná, Brazil.
authors.forename: Emanuela Carla Dos
authors.initials: ECD
authors.lastname: Santos
authors.affiliation: Biomedical Research Institute, Laboratory of Morphology, Hasselt, Belgium.
authors.forename: Ivo
authors.initials: I
authors.lastname: Lambrichts
authors.affiliation: OMFS IMPATH research group, Department of Imaging & Pathology, University Leuven and Oral & Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Ruben
authors.initials: R
authors.lastname: Pauwels
authors.affiliation: OMFS IMPATH research group, Department of Imaging & Pathology, University Leuven and Oral & Maxillofacial Surgery, University Hospitals Leuven, Leuven, Belgium; Department of Dental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Reinhilde
authors.initials: R
authors.lastname: Jacobs
mesh_terms: D054893:Cone-Beam Computed Tomography; D000071538:Cortical Bone / Q000000981:diagnostic imaging*; D006801:Humans; D066298:In Vitro Techniques; D015203:Reproducibility of Results; D012886:Skull / Q000000981:diagnostic imaging*; D014070:Tooth / Q000000981:diagnostic imaging*