Influence of acquisition parameters on the magnitude of cone beam computed tomography artifacts

Abstract

In both machines, increasing kVp and MAR are effective in decreasing the CBCT artifacts in all their magnitude when they are pronounced. Therefore, the professionals should choose one of those options or even both considering the purpose of the CBCT imaging and radiation dose for the patient.

Use of the metal artefact reduction tool in the identification of fractured endodontic instruments in cone‐beam computed tomography

“…It can be hypothesized that the action of the MAR tool was not effective in the present study, because only a small number of artefacts were created due to the small dimensions of the instrument (2 mm). In the same way, the lack of an improvement in their detection in filled canals can be attributed to the composition of gutta‐percha (mixture of zinc oxide and isoprene rubber), which has a low atomic number (Queiroz et al ), and thus does not generate sufficient artefacts to be significantly reduced by the MAR tool (Freitas et al , Queiroz et al ). Therefore, it can be inferred that the detection of fractured instruments in filled canals is difficult not because of the direct effect of the artefacts, but because the gutta‐percha and endodontic instruments produce a similar density on the final images that does not allow the root filling and instrument to be differentiated.…”

“…Likewise, Vasconcelos et al () reported an increase in artefact generation when evaluating the use of the MAR tool in filled canals. On the other hand, in studies using metallic materials such as implants (zirconia and titanium; Vasconcelos et al , Freitas et al ) and for evaluation of proximal caries in the presence of some materials with a high atomic number (Cebe et al ), the MAR tool was effective. Thus, it can be inferred that the MAR tool has a greater potential to correct artefacts generated by materials with a high atomic number, as suggested by Queiroz et al () when evaluating the impact of the use of the MAR tool in the presence of various dental materials, amongst them metallic alloys and gutta‐percha.…”

“…Although there are doubts about the effectiveness of the MAR tool, it is suggested that this tool works in the post‐processing stage, correcting highly dense or sparse regions in the image, that is, acting by applying a threshold in relation to the grey value average in the image and increasing the contrast‐to‐noise ratio (Bechara et al , Queiroz et al , Freitas et al ). The image noise was quantified by measuring the standard deviation of mean grey value (Freitas et al , Queiroz et al ). High standard deviation means high image noise, which is supposed to be well discerned in homogeneous structures.…”

“…According to the American Association of Endodontists (AAE), the American Academy of Oral and Maxillofacial Radiology (AAOMR) and the European Society of Endodontology (ESE), CBCT is only recommended in those cases in which lower dose two‐dimensional radiography does not provide sufficient information for confident diagnosis (AAE & AAOMR Joint Position Statement , ESE ). However, when the region of interest contains metallic objects (restorations, implants, endodontic instruments) or root canal fillings, the high atomic number and density of these materials lead to the generation of artefacts, which are structures seen in the reconstructed image, but which are not present in the real object (Vasconcelos et al , Freitas et al ). These artefacts compromise the diagnostic accuracy of CBCT, since they can lead to formation of white striae and dark areas around anatomical structures of interest, hindering or even rendering the diagnosis impossible (Bechara et al , Queiroz et al , Freitas et al , Koç et al ).…”

Incidental findings of implant complications on postimplantation CBCTs: A cross‐sectional study—Methodological issues

“…First, the authors only cited the CBCT machine used to acquire the examinations but ignored the acquisition parameters, such as voxel size. This is critical because it may influence on the image quality, affecting spatial resolution and contributing to the occurrence of the partial volume effect . Such effect has demonstrated to mainly affect the image of very thin structures, compromising the measurements of the bone crest and the identification of any perforation or resorption of the cortical plates.…”