title: Comparison of different methods to assess alveolar cleft defects in cone beam CT images.
abstract: OBJECTIVE
  This study aimed to evaluate the accuracy of three different methods for assessing the volume of cleft defects in CBCT images. The influence of field of view (FOV) and voxel sizes was also assessed.
  
  
  METHODS
  Using three radio-opaque plastic skulls, unilateral defects were created to mimic alveolar clefts and were filled with wax following the contralateral side contours. They were scanned in a CBCT unit using four different acquisition protocols, varying FOV and voxel sizes. Using three different methods, the defect/wax volume was evaluated on the images by defining: (1) the width, height and facial-palatal length of the defect in maximum intensity projection; (2) the areas of the defect on axial slices; and (3) the threshold and segmentation of the region of interest. The values obtained from each method using different acquisition protocols were compared with the real volume of the wax (gold standard) using ANOVA and Tukey's test.
  
  
  RESULTS
  Methods 2 and 3 did not differ from the gold standard (p > 0.05). Conversely, Method 1 presented statistically significant overestimated values (p < 0.01). No differences were found among the different FOV and voxel sizes (p > 0.05).
  
  
  CONCLUSIONS
  CBCT volumes proved reliable for the volumetric assessment of alveolar cleft defects, when using Methods 2 and 3 regardless of FOV and voxel sizes. It may be possible to improve surgical planning and outcomes by knowing the exact volume of grafting material needed prior to the surgical intervention.
authors.affiliation: 1 Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Gabriella Lopes
authors.initials: GL
authors.lastname: de Rezende Barbosa
authors.affiliation: 2 Division of Plastic and Reconstructive Surgery, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Jeyhan S
authors.initials: JS
authors.lastname: Wood
authors.affiliation: 3 Department of Dental Ecology, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Luiz A
authors.initials: LA
authors.lastname: Pimenta
authors.affiliation: 1 Department of Oral Diagnosis, Division of Oral Radiology, Piracicaba Dental School, University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Solange
authors.initials: S
authors.lastname: Maria de Almeida
authors.affiliation: 4 Department of Diagnostic Sciences, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Tyndall
mesh_terms: D000539:Alveolar Process / Q000002:abnormalities* / Q000000981:diagnostic imaging; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000706:statistics & numerical data; D002972:Cleft Palate / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography / Q000706:statistics & numerical data*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data; D008953:Models, Anatomic; D010159:Palate / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012984:Software
keywords: CBCT; alveolar bone grafting; orofacial cleft