Diagnostic efficacy of a modified low-dose acquisition protocol for the preoperative evaluation of mini-implant sites

Abstract

PurposeThe objective of this study was to compare the outcomes of surgical mini-implant placement when potential mini-implant sites were scanned using a lower-dose 180° acquisition protocol versus a conventional 360° acquisition protocol.Materials and MethodsTen dentate human skulls were used to provide sites for potential mini-implant placement. The sites were randomly divided into 2 groups: 360° and 180° cone-beam computed tomography (CBCT) acquisition protocols. A small-volume 180° CBCT scan and a 360° CBCT scan of each site were acquired using a Morita Accuitomo-170 CBCT machine and then a mini-implant was placed. A follow-up 360° CBCT scan was done as a gold standard to evaluate the location of the mini-implant and root perforation. Two raters evaluated the scans.ResultsNinety-eight percent of the mini-implants placed did not perforate any root structure. Two percent of the sites had an appearance suggestive of perforation. On a Likert scale, both raters agreed that their subjective evaluation of the diagnostic quality of the protocols, ability to make and read measurements of the sites, and preferences for the specified diagnostic task were comparable. The Cohen kappa showed high inter-rater and intra-rater agreement.ConclusionIn this ex vivo study, we found that the 180° rotational acquisition was as effective as the conventional 360° rotational acquisition for the preoperative evaluation of potential mini-implant sites.

Influence of scan mode (partial/full rotations) and FOV size in the formation of artefacts in cone beam CT

“…However, another strategy for optimising the radiation dose is reducing the rotation arc, which is available in some CBCT devices, such as Galileos (Sirona Dental Systems Inc., Bensheim, Germany), Promax 3D (Planmeca, Helsinki, Finland), i-CAT (Imaging Sciences International, Inc., Hatield, PA) and Accuitomo (J Morita Corp., Kyoto, Japan). 1,5,8,9 Thus, through filtered projection algorithms, the image is reconstructed in 360°. 8 It should be mentioned that, during partial rotation, the patient experiences a significant reduction in radiation dose.…”

“…1,5,8,9 Thus, through filtered projection algorithms, the image is reconstructed in 360°. 8 It should be mentioned that, during partial rotation, the patient experiences a significant reduction in radiation dose. 1,5,8,9 In addition, as the partial rotation occurs preferably through the posterior region of the skull, it avoids the direct exposure of radiosensitive organs, such as eyes and the thyroid gland.…”

“…1,6,7 Some devices provide the option of scanning with full (360°) or partial (~180°) rotation. 5,8 The device rotation degree determines the number of basis images acquired. 5,8 Theoretically, the higher the number of images, the greater the amount of information for volume reconstruction and the better the image quality.…”

“…5,8 The device rotation degree determines the number of basis images acquired. 5,8 Theoretically, the higher the number of images, the greater the amount of information for volume reconstruction and the better the image quality. 1,5,8 However, the radiation dose will be higher in comparison with a scanning with partial rotation, 5,8 as the area of interest in partial rotation will be irradiated only in ~180°, i.e.…”

“…5,8 Theoretically, the higher the number of images, the greater the amount of information for volume reconstruction and the better the image quality. 1,5,8 However, the radiation dose will be higher in comparison with a scanning with partial rotation, 5,8 as the area of interest in partial rotation will be irradiated only in ~180°, i.e. half of a full rotation, usually skipping a direct exposition to the face of the patient.…”