Zirconia implants interfere with the evaluation of peri-implant bone defects in cone beam computed tomography (CBCT) images even with artifact reduction, a pilot study.

OBJECTIVES: Three-dimensional cone beam computed tomography (CBCT) imaging can be considered, especially in patients with complicated peri-implantitis (PI). Artifacts induced by dense materials are the drawback of CBCT imaging and the peri-implant bone condition may not be assessed reliably because the artifacts are present in the same area. This pilot study investigates the performance of the artifact reduction algorithm (ARA) of the Planmeca Viso G7 CBCT device (Planmeca, Helsinki, Finland) with three different implant materials and imaging parameters. METHODS: Three pairs of dental implants consisting of titanium, zirconia, and fiber reinforced composite (FRC) were set into a pig mandible. A vertical defect simulating peri-implantitis bone loss was made on the buccal side of one of each implant. The defect was identified and measured by two observers and compared to the actual dimensions. In addition, the bone structure and the marginal cortex visibility between the implants were estimated visually. RESULTS: The bone defect and its dimensions with the zirconia implant could not be identified in any image with or without the metal artifact reduction algorithm. The bone defect of titanium and FRC implants were identified with all three imaging parameters or even without ARA. The interobserver agreement between the two observers was almost perfect for all categories analyzed. CONCLUSION: Peri-implantitis defect of the zirconia implant and the peri-implant bone structure of the zirconia implants cannot be recognized reliably with any ARA levels, or any imaging parameters used with the Planmeca Viso G7. The need for ARA when imaging the peri-implant bone condition of the titanium and FRC implants may be unnecessary.

Retrospective Analysis of Artifacts in Cone Beam Computed Tomography Images Used to Diagnose Chronic Rhinosinusitis.

BACKGROUND: Cone beam computed tomography (CBCT) is frequently used to corroborate the signs and symptoms of chronic rhinosinusitis (CRS). However, artifacts induced by dental restorations might complicate the diagnosis of CRS. Here, we assessed the frequency and location of artifacts in CBCT images taken to confirm the CRS. METHODS: All CBCT images of the patients referred to the Emergency Radiology unit, Turku University Hospital, with an indication of CRS in 2017 were re-examined. The prevalence of the artifacts was analyzed in three cross-sectional views and three horizontal levels delimited by anatomical landmarks. RESULTS: In total, 214 CBCT images of patients with CRS were evaluated. The diagnosis of apical periodontitis (AP) was impaired by artifacts present in 150/214 images (70%). The diagnosis of CRS was impaired in 5 of the 214 images (2.3%). The main origins of the artifacts were large dental fillings or crowns, and endodontic fillings were present in 95% (203/214) and 52% (111/214) of the images, respectively. CONCLUSIONS: AP as an etiology of CRS is possible to miss because of artifacts originating from dental and endodontic fillings in the CBCT images of the paranasal sinuses.

Intensity of artefacts in cone beam CT examinations caused by titanium and glass fibre-reinforced composite implants.

OBJECTIVES:: The aim was to compare titanium and glass fibre-reinforced composite (FRC) orbital floor implants using cone beam CT (CBCT). FRC implants are nonmetallic and these implants have not been analysed in CBCT images before. The purpose of this study is to compare the artefact formation of the titanium and the FRC orbital floor implants in CBCT images. METHODS:: One commercially pure titanium and one S-glass FRC with bioactive glass particles implant were imaged with CBCT using the same imaging values (80 kV, 1 mA, FOV 60 × 60 mm). CBCT images were analysed in axial slices from three areas to determine the magnitude of the artefacts in the vicinity of the implants. Quantified results based on the gray values of images were analysed using analysis-of-variance. RESULTS:: Compared to the reference the gray values of the titanium implant are more negative in every region of interest in all slices (p < 0.05) whereas the gray values of the FRC implant differ statistically significantly in less than half of the examined areas. CONCLUSIONS:: The titanium implant caused artefacts in all of the analysed CBCT slices. Compared to the reference the gray values of the FRC implant changed only slightly and this feature enables to use wider imaging options postoperatively.