CONE-BEAM COMPUTED TOMOGRAPHY DENSITY MEASUREMENT REPEATABILITY

Leszek Szalewski

Institute

Medical University of Lublin, Poland

Abstract

Introduction: Dental implants have been used for a long time as an option for patients who are partially or completely edentulous. Bone quantity and quality at the surgical site are key factors in an implant’s success.
Aim: To investigate the repeatability of density measurement in Cone-Beam Computed Tomography (CBCT) in different types of materials under four different acquisition protocols.
Material and Methods: The physical densities of three blocks (3x3x5cm) composed of plaster, acrylic, and wax were calculated. A VistaVoxS 3D CBCT device was used to scan each block at four different acquisition protocols varying field-of-view (5×5 and 13×5), kVp (98, 94, and 79), mA (11, 9, and 6), and voxel size (0.08 and 0.2 mm). After acquisitions, a virtual implant (16 mm x 5.2 mm) was centered in each block’s image, and the bone density tool in the AIS3DAPP 5.0 (Acteon Group, France) software was used to measure the HU along the implant’s thirds. For each implant, the mean HU values of the most anterior, posterior, left, and right sides were measured.
Results: HU values of Acrylic and Plaster were statistically significantly different among the 4 acquisition protocols. HU values of Wax were not statistically significantly different among the 4 acquisition protocols, but mean values were increased from protocol 1 (0.08 mm voxel size, 98 kVp, 11 mA, 5×5 FOV) to protocol 4 (0.2 mm voxel size, 79 kVp, 6 mA, 13×8 FOV).
Conclusions: The CBCT HU units were repeatable under the same acquisition protocols and significantly higher in high density materials despite of the field-of-view and acquisition parameters. The bone density tool demonstrated to be very useful when comparing the same acquisition parameters.
Keywords: Bone density, Cone beam computed tomography, grey values.