Effect of Different Cone Beam Computed Tomography Devices and Protocols on Image Quality for the Evaluation of Periodontal Structures / Efeito de Diferentes Dispositivos e Protocolos de Tomografia Computadorizada deFeixe Cônico na Qualidade de Imagem para Avaliação de Estruturas Periodontais

The quality of Cone Beam Computed Tomography (CBCT) images is directly influenced by scanning and visualization protocols. Evaluate the subjective quality of the Cone Beam Computed Tomography (CBCT) image of different devices and protocols for diagnosing periodontal structures and correlate the findings with the contrast-to-noise ratio (CNR). One dry dentate mandible was scanned by six CBCT devices: Accuitomo 3D 170, CS 9000, CS 9300, Eagle 3D, i-CAT Classic, and Orthophos XG 3D. All CBCT devices were adjusted to provide a spatial resolution closest to 0.2 mm, and a FOV height limited to less than 100 mm. Cross-sectional images were evaluated randomly. The buccal bone coverage, the periodontal ligament space and the amount of image noise were assessed. The statistics were calculated based on a logistic regression model with the significance level set at 5%. Protocols with large FOVs demonstrated significantly lower image quality. No statistical differences were found regarding buccal bone coverage between the CBCT devices. The CNR showed the highest value for the Accuitomo 60mm x 60mm HiFi 180°, followed by the Accuitomo 60mm x 60mm HiFi 360°, and lower values for the i-Cat Classic and Orthophos XG 3D devices. Most protocols studied presented good image quality in evaluating the buccal bone coverage and periodontal ligament space. However, the exam with the lowest FOV of the Accuitomo 60mm x 60mm HiFi 180° device showed superiority concerning the others.(AU)

A qualidade das imagens de tomografia computadorizada de feixe cônico (CBCT) é diretamente influenciada pelos protocolos de digitalização e visualização. Avaliar a qualidade subjetiva da imagem da Tomografia Computadorizada de Feixe Cone (CBCT) de diferentes aparelhos e protocolos para o diagnóstico de estruturas periodontais e correlacionar os achados com a razão contraste-ruído (RCR). Uma mandíbula dentada seca foi digitalizada por seis dispositivos CBCT: Accuitomo 3D 170, CS 9000, CS 9300, Eagle 3D, i-CAT Classic e Orthophos XG 3D. Todos os dispositivos CBCT foram ajustados para fornecer uma resolução espacial próxima a 0,2 mm e uma altura de FOV limitada a menos de 100 mm. Imagens transversais foram avaliadas aleatoriamente. A cobertura óssea vestibular, o espaço do ligamento periodontal e a quantidade de ruído da imagem foram avaliados. As estatísticas foram calculadas com base em um modelo de regressão logística com nível de significância de 5%. Protocolos com grandes FOVs demonstraram qualidade de imagem significativamente inferior. Não foram encontradas diferenças estatísticas em relação à cobertura óssea vestibular entre os dispositivos CBCT. O CNR apresentou o maior valor para o Accuitomo 60mm x 60mm HiFi 180°, seguido pelo Accuitomo 60mm x 60mm HiFi 360°, e valores menores para os dispositivos i-Cat Classic e Orthophos XG 3D. A maioria dos protocolos estudados apresentou boa qualidade de imagem na avaliação da cobertura óssea vestibular e do espaço do ligamento periodontal. Entretanto, o exame com menor FOV do aparelho Accuitomo 60mm x 60mm HiFi 180° apresentou superioridade em relação aos demais. (AU)

Efficacy of digital radiography for detecting a second mesiobuccal canal adjacent to unfilled or filled canals.

The aim of this study was to assess the diagnostic accuracy of digital periapical radiography for the detection of the second mesiobuccal (MB2) canal when the adjacent canals are unfilled or filled with gutta percha. Forty human maxillary first molars were selected, 20 of which had an MB2 canal. The presence or absence of the MB2 canal was confirmed using microcomputed tomography. Digital periapical radiographs of each tooth were obtained from 3 horizontal angles before and after the adjacent root canals were filled with gutta percha. Three experienced oral radiologists evaluated all images and indicated the presence or absence of the MB2 canal using a confidence scale of 5 points. To assess intraobserver and interobserver agreement, weighted kappa coefficients were calculated. The diagnostic test (sensitivity, specificity, and accuracy) and area under the receiver operating characteristic curve (Az) values were calculated and compared between groups (n = 40): radiographs of the first molars with unfilled adjacent canals and radiographs of the same teeth with filled adjacent canals. For all observers, intraobserver reproducibility ranged from substantial (0.70) to almost perfect (0.86), and interobserver reproducibility ranged from fair (0.39) to substantial (0.67). Similar values of specificity and Az for the detection of the MB2 canal were observed with unfilled and filled adjacent canals. The sensitivity and accuracy were slightly greater when the adjacent root canals were filled with gutta percha. Detection of the MB2 canal on digital periapical radiographs can be challenging even when obtained at varying horizontal angles, and the presence of gutta percha does not influence the detection.

Mental Foramen and Anterior Loop Anatomic Characteristics: A Systematic Review and Meta-analysis of Cross-sectional Imaging Studies.

INTRODUCTION: The present study aimed to review the epidemiologic, topographic, and morphometric aspects of the mental foramen (MF) and anterior loop (AL) on cone-beam computed tomographic imaging studies. METHODS: An International Prospective Register of Systematic Reviews (PROSPERO)-registered systematic review (CRD42018112991) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two reviewers independently performed data extraction from observational studies that evaluated MF and AL on 7 electronic databases. MedCalc (MedCalc Software bv, Ostend, Belgium) software was used to perform a meta-analysis with a 95% confidence level. RESULTS: Of 1545 articles, 66 met the inclusion criteria, totaling 14,233 patients from 5 continents, with a total of 6655 females and 5884 males (some studies did not report sex), with an age range between 8 and 89 years. The most prevalent shapes of MF were oval (48.72%) and circular (44.36%), and the most frequent horizontal positions were between premolars (43.66%) and in line with the long axis of the second premolar (43.12%). CONCLUSIONS: Based on the articles that assessed AL, the mean prevalence was 43.18%, with most studies reporting bilateral localization as the most prevalent.

Comparison of digital image displays performance in the detection of artificial internal root resorptions lesions.

OBJECTIVE: To compare the diagnostic efficacy of different devices for visualizing digital images in detecting simulated internal root resorption (IRR). METHODS: 26 uniradicular human teeth were sectioned along its long axis and randomly divided into two groups. Then, they were submerged in hydrochloric acid (HCl) P.A 37% at different times to make two types of defects: Type 1 (2 hours), and type 2 (3 hours). Digital periapical radiographs were acquired in three moments: before section, after section and after immersion in acid. The images were evaluated on three different devices: 27-inch iMac Desktop, 8-inch Android Tablet, and 5.5-inch iPhone 8 Plus using a 5-point scale. RESULTS: The sensitivity and accuracy values were higher with the use of the Android Tablet, for both types of defects. For the values of the area under ROC curve, higher results were observed with the Android Tablet and lower results with the iMac, showing a significant difference (p < 0.05) when comparing the use of the iMac with the Android Tablet and iPhone 8, for type 1 defects. When comparing the different devices, in the evaluation of images of type 2 defects, the values showed no statistical difference, regardless of the device evaluated (p > 0.05). CONCLUSIONS: The size of the lesion interferes with the detection capacity in the image. However, the use of portable devices does not impair the diagnosis of IRR, regardless of size and the dental practioners may use different devices/display, under optimal viewing conditions, to detect IRR lesions, without jeopardizing the diagnostic ability.

Influence of Cone Beam Computed Tomography Settings on Implant Artifact Production: Zirconia and Titanium.

PURPOSE: This in vitro study assessed the artifact production related to titanium and zirconia implants in cone beam computed tomography (CBCT) and compared the effect of different protocol settings on image quality for both materials. MATERIALS AND METHODS: A titanium implant and a zirconia implant were placed in a dry mandible. CBCT scans were obtained separately for each implant using the ProMax 3D (Planmeca) unit; 20 protocols were tested with varying kilovoltage (70 to 90 kVp) and resolution (high and low), and with and without a metal artifact reduction tool. Standard deviation and contrast-noise ratio were calculated in regions of interest adjacent and distant to the implant. RESULTS: The zirconia produced more artifacts and its images were more affected by the different protocols than titanium. High kVps and an activated metal artifact reduction tool decreased the standard deviation values related to both implants. Activation of the metal artifact reduction tool also increased contrast-noise ratio values for both implants, whereas increasing kVp improved them only on titanium images. The standard deviation and contrast-noise ratio were not affected by resolution. CONCLUSION: The zirconia implant generated more image artifacts than the titanium implant. Increasing kVp and the metal artifact reduction tool are efficient in decreasing the CBCT artifacts for both implants, whereas resolution does not affect their production.

Diagnosis of vertical root fracture in teeth close and distant to implant: an in vitro study to assess the influence of artifacts produced in cone beam computed tomography.

OBJECTIVES: To evaluate the influence of artifacts produced by zirconium implant on the diagnosis of vertical root fracture (VRF) in teeth close and distant to the implant in cone beam computed tomography (CBCT) images. We also determined if kilovoltage (kVp) and metal artifact reduction (MAR) tool could influence this diagnosis. MATERIALS AND METHODS: Twenty single-root teeth were divided in control and fractured groups (n = 10). The teeth were randomly positioned in the first and second and right and left pre-molar alveoli of a dry human mandible. CBCT exams were acquired using a ProMax 3D unit with varying kVp (70, 80, or 90 kVp), with or without MAR, and with and without a zirconium implant placed in the alveolus of first right molar. The images were evaluated by five observers. The area under the receiver operating characteristic curve (ROC), sensitivity, and specificity were calculated and compared by analysis of variance with a significance level of 5%. RESULTS: In general, ROC and sensitivity were not affected by the factors studied (p > 0.05). The main effects occurred in specificity; when implant was used without MAR, the values were lower for tooth 45 for all kVps (p = 0.0001). CONCLUSIONS: Artifacts produced in the vicinity of teeth with suspected VRF impair the diagnosis by decreasing the specificity, because they can mimic the VRF line generating false positives. However, MAR improves the specificity, being its use recommended when metallic objects are present near teeth with suspected VRF. CLINICAL RELEVANCE: Since nowadays, many patients who undergo CBCT show implants and they definitively produce artifacts, it is important to evaluate the influence of such artifacts in the diagnosis of teeth that are close to the generator-artifact object.

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

AIM: To evaluate the influence of kilovoltage (kVp) and metal artifact reduction tool (MAR) on the magnitude of cone beam CT (CBCT) artifacts. METHODS: A titanium and zirconia implants were inserted alternately in a posterior region of a mandible. CBCT exams were acquired with ProMax 3D (Planmeca Oy, Helsinki, Finland) and Picasso Trio machines (Vatech, Hwaseong, South Korea) using 70 kVp, 80 kVp and 90 kVp with and without MAR activation. The other exposure factors remained fixed at 5mA, field of view 80 × 50 mm and voxel 0.20 mm. The scans were performed before and after the insertion of the implants. Regions of interest were determined in different distances from the artifact production area (15, 25 and 35 mm) in an axial image, in which standard deviation (SD) of grayscale values was measured and contrast-to-noise ratio (CNR) was calculated. Analysis of variance was used to compare the data. RESULTS: Overall, in cases where the artifact was pronounced, MAR was efficient in reducing SD values. MAR also improved the CNR of ProMax images, but did not affect the Picasso images. Additionally, the higher was the kVp, the lower was the SD value and the higher was the CNR in both machines. CONCLUSION: 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.

Evaluation of artifacts generated by zirconium implants in cone-beam computed tomography images.

OBJECTIVE: To evaluate zirconium implant artifact production in cone beam computed tomography images obtained with different protocols. STUDY DESIGN: One zirconium implant was inserted in an edentulous mandible. Twenty scans were acquired with a ProMax 3D unit (Planmeca Oy, Helsinki, Finland), with acquisition settings ranging from 70 to 90 peak kilovoltage (kVp) and voxel sizes of 0.32 and 0.16 mm. A metal artifact reduction (MAR) tool was activated in half of the scans. An axial slice through the middle region of the implant was selected for each dataset. Gray values (mean ± standard deviation) were measured in two regions of interest, one close to and the other distant from the implant (control area). The contrast-to-noise ratio was also calculated. RESULTS: Standard deviation decreased with greater kVp and when the MAR tool was used. The contrast-to-noise ratio was significantly higher when the MAR tool was turned off, except for low resolution with kVp values above 80. Selection of the MAR tool and greater kVp resulted in an overall reduction of artifacts in images acquired with low resolution. CONCLUSIONS: Although zirconium implants do produce image artifacts in cone-bean computed tomography scans, the setting that best controlled artifact generation by zirconium implants was 90 kVp at low resolution and with the MAR tool turned on.

Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification.

This study aimed at evaluating the validity of cone-beam computed tomography (CBCT) for assessing mandibular bone quality using the Klemetti classification. The morphology of the endosteal mandibular cortex of 30 (60 hemi-mandibles) postmenopausal women between the ages of 45 and 80 years was evaluated based on the Klemetti classification in panoramic radiographs used as reference images. Afterwards, panoramic reconstruction and cross-sectional slices of CBCT examinations of these patients were analyzed and categorized according to the same classification. All the images were assessed by two oral radiologists. The McNemar-Bowker test compared the agreement between the CBCT images and the reference images. No differences were found between the diagnostic results based on panoramic radiography and panoramic reconstruction. However, the mean scores for the cross-sectional evaluation were higher, and the results, statistically different from the others. Based on the disagreement found between the panoramic radiographs and the CBCT cross-sectional slices, the Klemetti classification is not an adequate means of assessing bone quality with CBCT. On the other hand, the higher values found for the cross-sectional slices could be associated with better visibility on the CBCT images.

Validation of cone-beam computed tomography as a predictor of osteoporosis using the Klemetti classification

Abstract This study aimed at evaluating the validity of cone-beam computed tomography (CBCT) for assessing mandibular bone quality using the Klemetti classification. The morphology of the endosteal mandibular cortex of 30 (60 hemi-mandibles) postmenopausal women between the ages of 45 and 80 years was evaluated based on the Klemetti classification in panoramic radiographs used as reference images. Afterwards, panoramic reconstruction and cross-sectional slices of CBCT examinations of these patients were analyzed and categorized according to the same classification. All the images were assessed by two oral radiologists. The McNemar-Bowker test compared the agreement between the CBCT images and the reference images. No differences were found between the diagnostic results based on panoramic radiography and panoramic reconstruction. However, the mean scores for the cross-sectional evaluation were higher, and the results, statistically different from the others. Based on the disagreement found between the panoramic radiographs and the CBCT cross-sectional slices, the Klemetti classification is not an adequate means of assessing bone quality with CBCT. On the other hand, the higher values found for the cross-sectional slices could be associated with better visibility on the CBCT images.

Vertical bone measurements from cone beam computed tomography images using different software packages.

This article aimed at comparing the accuracy of linear measurement tools of different commercial software packages. Eight fully edentulous dry mandibles were selected for this study. Incisor, canine, premolar, first molar and second molar regions were selected. Cone beam computed tomography (CBCT) images were obtained with i-CAT Next Generation. Linear bone measurements were performed by one observer on the cross-sectional images using three different software packages: XoranCat®, OnDemand3D® and KDIS3D®, all able to assess DICOM images. In addition, 25% of the sample was reevaluated for the purpose of reproducibility. The mandibles were sectioned to obtain the gold standard for each region. Intraclass coefficients (ICC) were calculated to examine the agreement between the two periods of evaluation; the one-way analysis of variance performed with the post-hoc Dunnett test was used to compare each of the software-derived measurements with the gold standard. The ICC values were excellent for all software packages. The least difference between the software-derived measurements and the gold standard was obtained with the OnDemand3D and KDIS3D (-0.11 and -0.14 mm, respectively), and the greatest, with the XoranCAT (+0.25 mm). However, there was no statistical significant difference between the measurements obtained with the different software packages and the gold standard (p> 0.05). In conclusion, linear bone measurements were not influenced by the software package used to reconstruct the image from CBCT DICOM data.

Vertical bone measurements from cone beam computed tomography images using different software packages

This article aimed at comparing the accuracy of linear measurement tools of different commercial software packages. Eight fully edentulous dry mandibles were selected for this study. Incisor, canine, premolar, first molar and second molar regions were selected. Cone beam computed tomography (CBCT) images were obtained with i-CAT Next Generation. Linear bone measurements were performed by one observer on the cross-sectional images using three different software packages: XoranCat®, OnDemand3D® and KDIS3D®, all able to assess DICOM images. In addition, 25% of the sample was reevaluated for the purpose of reproducibility. The mandibles were sectioned to obtain the gold standard for each region. Intraclass coefficients (ICC) were calculated to examine the agreement between the two periods of evaluation; the one-way analysis of variance performed with the post-hoc Dunnett test was used to compare each of the software-derived measurements with the gold standard. The ICC values were excellent for all software packages. The least difference between the software-derived measurements and the gold standard was obtained with the OnDemand3D and KDIS3D (-0.11 and -0.14 mm, respectively), and the greatest, with the XoranCAT (+0.25 mm). However, there was no statistical significant difference between the measurements obtained with the different software packages and the gold standard (p> 0.05). In conclusion, linear bone measurements were not influenced by the software package used to reconstruct the image from CBCT DICOM data.

Influence of the milliamperage settings on cone beam computed tomography imaging for implant planning.

PURPOSE: To evaluate the influence of the milliamperage settings on cone beam computed tomography (CBCT) images for qualitative and quantitative preoperative implant planning. MATERIALS AND METHODS: Eight dry mandibles were scanned under different milliamperage values (2, 4, 6.3, 8, 10, 12, and 15 mA) available for selection on the Kodak 9000 CBCT unit. Cross-sectional slices of incisor, canine, premolar, first molar, and second molar regions were analyzed by three oral radiologists. A subjective image quality evaluation of the height measurements compared with the real measurements obtained in the mandible were performed. After 30 days, 25% of the sample was reevaluated to obtain the reproducibility of the results. RESULTS: The weighted-kappa coefficient and intraclass correlation coefficient for intra- and interobserver agreement varied between moderate and substantial agreement for the image quality evaluation, and excellent agreement was found for the bone measurements. For the image quality evaluation, the Friedman test showed a negative influence of the milliamperage setting only when the lowest values (2 and 4 mA) were used; for the measurements, one-way analysis of variance with the post hoc Tukey test showed that milliamperage settings did not influence their accuracy. However, images obtained with 6.3 mA were closest to the real measurements. CONCLUSION: On the basis of this study of dried skulls using CBCT, it was determined that image quality degradation was not significantly improved when the milliamperage setting was increased above 6.3 mA, whereas a milliamperage level below 6.3 mA resulted in degradation of the image quality. Therefore, significant dose reduction can be achieved with diagnostically satisfactory image quality on CBCT exams for implant planning by reducing the milliamperage setting.

Oblique or orthoradial CBCT slices for preoperative implant planning: which one is more accurate?

AIM: To assess which slice inclination would be more accurate in measuring sites for implant placement: the oblique or the orthoradial slice. METHODS: Five regions of eight edentulous mandibles were selected (incisor, canine, premolar, first molar and second molar). The mandibles were scanned with a Next Generation i-CAT CBCT unit. Two previously calibrated oral radiologists performed vertical measurements in all the selected regions using both the oblique and orthoradial slices. The mandibles were sectioned in all the evaluated regions in order to obtain the gold standard. The Wilcoxon signed rank test compared the measurements obtained in the oblique and orthoradial slices with the gold standard. RESULTS: The bone height measurements for the first and second molar regions using the orthoradial slices were statistically different from the gold standard. CONCLUSIONS: Using the orthoradial slices to obtain cross-sectional images may offer insufficient accuracy for implant placement in the posterior region...

Influence of cone-beam computed tomography enhancement filters on diagnosis of simulated external root resorption.

INTRODUCTION: The aim of this study was to determine if cone-beam computed tomography (CBCT) enhancement filters influence the diagnosis of simulated external root resorption (ERR). METHODS: Buccal, mesial, and distal root surfaces of 20 single-rooted premolar teeth were evaluated for the presence or absence of simulated defects. Images were obtained using a Classic i-CAT CBCT device (Imaging Sciences International, Inc, Hatfield, PA) and analyzed by 3 oral radiologists. Evaluations were performed with and without CBCT filters. Accuracy, sensitivity, specificity, and positive and negative predictive values were determined. The McNemar test verified the disagreement between all images versus the gold standard and original images versus images with filters; P values < .05 were considered statistically significant. Inter- and intraobserver agreement was calculated by the kappa test. RESULTS: The means of intra- and interobserver agreement ranged from good to excellent. Sharpen 3×3 had the highest sensitivity (0.64), accuracy (0.62), and negative predictive value (0.33). Specificity was the highest (0.56) for S9, Smooth, Smooth 3×3, and Angio Sharpen High filters. Positive predictive values were the highest (0.81) for the Smooth 3×3 and Angio Sharpen High filters. The McNemar test showed statistically significant differences from the gold standard for all images (P < .05) as well as for original images versus images with the Shadow filter (P = .01). The other filters did not show statistically significant differences from the original images. CONCLUSIONS: The influence of enhancement CBCT filters on ERR diagnosis is small. The Sharpen 3×3 filter gave the best results and the Shadow filter the worst results.