Oral and maxillofacial radiology
Efficacy of a cone beam computed tomography metal artifact reduction algorithm for the detection of peri-implant fenestrations and dehiscences

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Objective

To determine whether the use of a metal artifact reduction (MAR) algorithm improves the detection of peri-implant fenestrations and dehiscences on cone beam computed tomography scans.

Study Design

One hundred titanium fixtures were implanted into bovine ribs after the creation of defects simulating fenestrations and dehiscences. Images were acquired using four different protocols, namely, A2 (MAR on, voxel 0.2 mm), A3 (MAR on, voxel 0.3 mm), B2 (MAR off, voxel 0.2 mm), and B3 (MAR off, voxel 0.3 mm). For all protocols, receiver operating characteristic (ROC) curves were determined. Values for the areas under the ROC curves (Az) were subjected to analysis of variance.

Results

Az values were not statistically different among protocols regardless of the defect type (P > .05).

Conclusions

The MAR algorithm tested by us did not improve the diagnosis of peri-implant fenestrations and dehiscences with use of either the 0.2 mm or the 0.3 mm voxel sizes.

Section snippets

Materials and Methods

The Research Ethics Committee of Piracicaba Dental School, State University of Campinas (protocol 084/2011), approved this study without restrictions.

Fresh, soft tissue–free bovine ribs were used to simulate alveolar bone, as previously reported.7, 8 Before implant placement, the bone defects were created with a spherical bur (3017 HL; KG Sorensen, São Paulo, SP, Brazil). Defects were 2.5 mm in diameter, with an elliptical (fenestrations) or half-elliptical (dehiscences) shape. Dehiscences were

Results

Means and standard deviations for the kappa test are shown in Table I. Intraobserver agreement ranged from moderate to good, and interobserver agreement ranged from moderate to excellent.

The Az values for diagnosis of fenestrations and dehiscences are shown in Table II. Values were higher for fenestrations than for dehiscences, and neither the use of MAR nor the decrease in voxel size led to superior diagnostic accuracy for either defect type (P = .957 for fenestrations; P = .253 for

Discussion

When high-density structures, such as dental implants, are present in CBCT scans, beam hardening and scattering artifacts can affect image quality and impair the diagnosis of conditions such as radicular fractures or peri-implant fenestrations and dehiscences.4, 11, 12, 13, 14, 15 Peri-implant defects, such as fenestrations and dehiscences, may compromise implantation success.1 Thus, once these defects are suspected, patients may benefit from CBCT imaging, since it is an excellent aid to

Conclusions

The MAR algorithm tested did not improve the diagnosis of peri-implant fenestrations and dehiscences when either the 0.2-mm or the 0.3-mm voxel size was used.

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    Part of the results of this study were previously presented as posters at the 31st SBPqO Annual Meeting (2014) and at the 20th International Congress of Dento-Maxilo-Facial Radiology (2015). An abstract was published in the 28th volume of the journal Brazilian Oral Research (page 374).

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