Lucas de Paula Lopes Rosado

We aimed to evaluate the effect of varying the tube current and the Metal Artifact Reduction (MAR) tool on the detection of the missing second mesiobuccal (MB2) canal. Forty maxillary molars (20 with and 20 without MB2) were selected and confirmed by micro-CT. The teeth underwent endodontic preparation, with the canals filled using gutta-percha and a silver-palladium metal post. CBCT scans were acquired using the OP300 Maxio system (voxel size: 0.085 mm, FOV: 50 x 50 mm) at 4 mA, 6.3 mA, and 12.5 mA, with and without MAR activation. The areas under the receiver operating characteristic curves (AUCs), sensitivities, and specificities were calculated for five examiners and compared using two-way ANOVA (p < 0.05). Intra- and interexaminer agreements were assessed using the weighted Kappa test. The AUC values ranged from 0.90 to 0.94, sensitivity from 0.75 to 0.78, and specificity from 0.89 to 0.95. Intra- and interexaminer indices ranged from moderate to substancial. Based on the tube current settings or MAR activation, there were no significant differences in the MB2 canal detection. Therefore, varying the tube current and MAR tool activation did not affect MB2 canal detection, with values close to 4 mA without MAR activation recommended in this scenario to reflect a better dose-benefit ratio.

Coelho-Silva F, et al. Imaging Sci Dent. 2025 Apr;55:e9. https://doi.org/10.5624/isd.20240218

This study aimed to evaluate the influence of the metal post composition, tooth location in the dental arch, and metal artifact reduction (MAR) on vertical root fracture (VRF) diagnosis in cone beam computed tomography (CBCT). Twenty-two unirradicular premolars (12 sound and 10 fractured) and two alveolar sockets of a mandible (anterior and posterior regions) composed the sample. CBCT scans of each tooth with a metal post placed into the root canal—silver–palladium (Ag–Pd), cobalt–chromium (Co–Cr), or nickel–chromium (Ni–Cr)—were individually acquired for each mandibular region, and two conditions of MAR, using a OP300 device (Instrumentarium, Finland). Images were assessed by five evaluators independently for VRF detection. Diagnostic values were calculated and compared among all groups using multi-way ANOVA with Tukey post hoc test to investigate the effect of post material, anatomical region, and MAR on VRF diagnosis (α = 0.05). Values of area under the receiver operating curve and specificity were not influenced by the studied factors (p > 0.05). Sensitivity was influenced by the MAR in both mandibular regions (p < 0.05). In the anterior region, sensitivity values increased when the MAR was enabled, regardless of the metal post material (p < 0.05). Similar behavior was noticed in the posterior region for Ni–Cr (p < 0.05) but not for Ag-Pd and Co–Cr posts (p > 0.05). The MAR improved the sensitivity in VRF diagnosis for all tested metal posts in the mandibular anterior region and for the Ni–Cr post in the mandibular posterior region. Therefore, for images obtained in the OP300 CBCT device, activation of the MAR is suggested in these cases.

Ruiz DC, et al. Imaging Sci Dent. 2024 Jun;54(2):139-145. https://doi.org/10.5624/isd.20230233

Objectives: To assess the distortion of high-density materials using two CBCT devices presenting convex triangular and cylindrical fields of view (FOVs). Methods and materials: Four high-density cylinders were individually placed in a polymethylmethacrylate phantom. 192 CBCT scans were acquired using the convex triangular and cylindrical FOVs of Veraviewepocs^® R100 (R100) and Veraview^® X800 (X800) devices. Using Horos^TM’s software, two oral radiologists determined the cylinders’ horizontal and vertical dimensional alterations. Nine oral radiologists subjectively identified each cylinder’s axial shape distortion. Statistical analysis comprised Multiway ANOVA (α = 5%), and the Kruskal–Wallis test. Results: The distortion in the axial plane was greater in the convex triangular FOVs for both devices in almost all the materials (p < 0.05). The evaluators subjectively identified a shape distortion in both FOVs for R100 device (p < 0.001), while no distortion was identified for X800 device (p = 0.620). A vertical magnification of all materials was observed in both FOVs for both devices (p < 0.05). No differences among vertical regions (p = 0.988) nor FOVs (p = 0.544) were found for the R100 device, while all materials showed higher magnification in all regions in the cylindrical FOV (p < 0.001) of the X800 device. Conclusions: The convex triangular FOV influenced the axial distortion of the high-density materials in both devices. A vertical magnification was observed in both FOVs of both devices, but it was greater in the cylindrical FOV of the X800 device.

Background: During oral rehabilitation, dental implants in the posterior maxilla can penetrate the maxillary sinus. The aim was to evaluate the presence of maxillary sinus abnormalities in patients with dental implants in the posterior maxillary region using cone-beam computed tomography (CBCT) images. Materials and Methods: This was a retrospective cross-sectional study, and CBCT scans of 199 patients (459 dental implants) were evaluated. Implants were assessed according to their relative location to the maxillary sinus floor (up to 2 mm from the maxillary sinus cortex, within 2 mm to intimate contact with the maxillary sinus cortex, apical third inside the maxillary sinus, two-thirds or more inside the maxillary sinus) and bone-fixation tissue (Alveolar ridge or Bone graft). Maxillary sinus abnormalities were classified. Kappa and Weighted Kappa and the Kruskal–Wallis test were applied. Results: A higher prevalence of mucosal thickening and non-specific opacification were observed in implants located within 2 mm to intimate contact with the cortex of the maxillary sinus floor. Of the 66 implants with apical thirds located inside the maxillary sinus, 31 (46.7%) were associated with sinus abnormalities and of all implants (n = 5) with two-thirds or more located inside the maxillary sinus, all of these were associated with sinus abnormalities. No association was observed in relation to implant bone-fixation tissue. Conclusions: This study found a significant association between dental implant placement near or within the sinus and sinus abnormalities, mainly mucosal thickening and non-specific opacification.

Background: There is no established acquisition protocol based on scientific evidence for the acquisition of cone‐beam computed tomography (CBCT) exams to evaluate the temporomandibular joint (TMJ).Objectives: To evaluate the influence of acquisition protocols and jaw positioning on the diagnostic accuracy of TMJ condylar morphological alterations (CMA), dimension, position and excursion.Methods: Thirty‐six TMJs on 18 dry skulls were imaged using a CBCT unit (OP300 Maxio, Instrumentarium, Tuusula, Finland) at two exposure settings (4.5 and 6.3 mA), three voxel resolutions (0.085, 0.125 and 0.280 mm), three jaw positions (concentric, anteriorised and posteriorised) and three jaw excursions (normoexcursion, hyperexcursion and hypoexcursion). The macroscopic anatomy examination and high‐resolution CBCT images were used as ground truth for CMA. Twenty‐five TMJs had at least one CMA with 11 healthy TMJs serving as controls. Three experienced oral and maxillofacial radiologists evaluated the parasagittal images for the presence of CMA, position and excursion and measured dimensions. The area under the ROC curve, sensitivity and specificity were calculated. Weighted Kappa (α = 0.05) was used to determine intra‐ and interexaminer reliability and comparisons between dependent variables analysed by Analysis of Variance at an a prior level of significance of 0.05.Results: The agreement of the evaluation of the position and excursion with the reference standard was high, independent of the protocol (range, 0.75–0.91). Various combinations of acquisition protocols and jaw position did not influence the CMA evaluation. Erosion was overdiagnosed in protocols with larger voxel sizes and the detection of osteophytes greater in images with smaller voxel sizes. The anteroposterior dimension was greater in the open jaw position (p < .05).Conclusion: CBCT protocols using reduced radiation exposure from the CBCT machine evaluated in this study can be used to assess condylar morphology, dimension, position and excursion, without compromising diagnostic performances for these parameters.

Objective To evaluate the potential of maxillary molar dimensions as predictors of the presence of the second mesiobuccal (MB2) canal. Methods Micro-computed tomography scans were obtained from 47 maxillary molars, out of which 26 had the MB2 canal. The distance between root canals, extension of the canals, and thickness of surrounding dentin were obtained from axial images at the furcation level, 3 mm from the apex, and 5 mm from the apex. The association between the measurements and the presence of the MB2 canal was assessed using multiple logistic regression and odds ratio. Results At the furcation level, the bucco-palatal extension of the MB1 canal significantly decreased the chance of the presence of the MB2 canal. Regarding the thickness of surrounding dentin measurements, the mesial and distal aspects of the MB1 canal at 3 mm from the apex were statistically significant to decrease and increase the chance of presence of the MB2 canal, respectively. Regarding the extension of the canals, only buccal-palatal extension seems to decrease the chance of the presence of the MB2 canal. Conclusion The presence of the MB2 canal in the mesiobuccal root of maxillary molars is associated with the bucco-palatal extension and surrounding dentin thickness of the first mesiobuccal canal, and seems to be unrelated to the dimensions of the distobuccal and palatal roots.