title: CBCT-based volume of simulated root resorption - influence of FOV and voxel size.
abstract: OBJECTIVE
  To examine the influence of the field of view (FOV) and voxel size on the measurement of the volume of simulated internal root resorption (IRR) lesions through cone-beam computed tomography (CBCT).
  
  
  METHODS
  Eleven single-rooted teeth with IRR simulated by acid demineralization were studied. CBCT images were acquired using large FOV (voxel sizes of 0.200, 0.250 and 0.300 mm) and limited FOV (voxel sizes of 0.076, 0.100 and 0.200 mm). The IRR volumes were calculated using the Dolphin(®) software. Volumetric measurements were validated using IRR silicone putty casts. The analysis of variance (anova) for randomized block design complemented with the Tukey's test was employed.
  
  
  RESULTS
  IRR volumes obtained using voxel sizes of 0.200 and 0.250 mm were similar (P > 0.05). However, both these values were significantly different from that obtained using the 0.300-mm voxel (P < 0.05). There was no significant difference between IRR volumes measured through voxel sizes of 0.076 and 0.100 mm (P > 0.05), but both differed significantly from that obtained through the 0.200-mm voxel (P < 0.05). There was no significant difference between the volumetric measurements of the 0.200-mm voxel images of the restricted and large FOV protocols. The mean volumes of the silicone casts were smaller than those calculated using a 0.200-mm voxel, but were similar to those obtained using voxel sizes of 0.076 and 0.300 mm.
  
  
  CONCLUSIONS
  Despite the FOV protocol, voxel size can influence measurement of simulated IRR volumes. The importance of standardization of CBCT image acquisition protocols is emphasized, especially during follow-up of an IRR lesion, to prevent misinterpretation of its extent, which can create a bias in clinical decisions.
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: P F
authors.initials: PF
authors.lastname: Da Silveira
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: M P
authors.initials: MP
authors.lastname: Fontana
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: H W
authors.initials: HW
authors.lastname: Oliveira
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: M B
authors.initials: MB
authors.lastname: Vizzotto
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Montagner
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: H L
authors.initials: HL
authors.lastname: Silveira
authors.affiliation: Department of Surgery and Orthopedics, Oral Radiology Division, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: H E
authors.initials: HE
authors.lastname: Silveira
mesh_terms: D054893:Cone-Beam Computed Tomography; D006801:Humans; D066298:In Vitro Techniques; D011857:Radiographic Image Interpretation, Computer-Assisted; D012391:Root Resorption / Q000000981:diagnostic imaging*; D012984:Software
keywords: cone-beam computed tomography; measurements; root resorption