Image quality for visualization of cracks and fine endodontic structures using 10 CBCT devices with various scanning protocols and artefact conditions.

The aim of this study was to evaluate CBCT exposure protocols and CBCT devices in terms of image quality for the detection of cracks and fine endodontic structures using 3 conditions of metallic artifacts. An anthropomorphic phantom containing teeth with cracks, isthmus, narrow canal, and apical delta was scanned using ten CBCT devices. A reference industrial CT image was used to detect and measure all structures. Three conditions were created: (1) metal-free, (2) 'endo' and (3) 'implant' with metallic objects placed next to the teeth of interest. For each condition, three protocols were selected: medium field of view (FOV) standard resolution, small FOV standard and high resolution. The results showed that only small FOV high-resolution metal-free images from two devices (A and H) were appropriate to visualize cracks. For fine structure identification, the best result was observed for small FOV high resolution. However, the visualization significantly worsened in the presence of metallic artefacts. The ability of CBCT images for visualizing cracks is restricted to certain CBCT devices. Once metallic artefacts are present, crack detection becomes unlikely. Overall, small FOV high-resolution protocols may allow detection of fine endodontic structures as long as there are no high-dense objects in the region of interest.

Effect of foraminal enlargement on microcrack formation and apical transportation: a nano-CT assessment.

The aim of this study was to evaluate the foraminal enlargement and its influence on microcrack formation and apical transportation in root canals with apical curvature. Eighteen maxillary lateral incisors with apical curvature were selected by using micro-CT images. Root canals were randomly divided in two groups (n = 9) according to root canal preparation using two working lengths: 1 mm short of the apical foramen (control group) and 1 mm beyond the apical foramen (foraminal enlargement). For both groups Reciproc Blue R40 was used for root canal instrumentation. Specimens were scanned by nano-CT (UniTOM HR) before and after root canal preparation. Percentage, length, and width of microcracks, and apical transportation were assessed. Kappa, chi-square and McNemar tests were used for qualitative analyses while paired and unpaired t-test were used for quantitative analyses (α = 0.05). For both groups, rather similar and low percentages of microcracks were observed before root canal preparation (P > 0.05). The foraminal enlargement promoted new microcracks, not observed in the control group. An increase in microcrack length was observed when the foraminal enlargement was performed (P < 0.05). Higher apical transportation was observed when foraminal enlargement was performed (P < 0.05). Foraminal enlargement using a heat-treated reciprocating file size 40 promoted microcracks and higher apical transportation than root canal preparation up to 1 mm short of apical foramen.

How do imaging protocols affect the assessment of root-end fillings?

Objectives: This study investigated the impact of micro-computed tomography (micro-CT)-based voxel size on the analysis of material/dentin interface voids and thickness of different endodontic cements. Materials and Methods: Following root-end resection and apical preparation, maxillary premolars were filled with mineral trioxide aggregate (MTA), Biodentine, and intermediate restorative material (IRM) (n = 24). The samples were scanned using micro-CT (SkyScan 1272; Bruker) and the cement/dentin interface and thickness of materials were evaluated at voxel sizes of 5, 10, and 20 µm. Analysis of variance and the Tukey test were conducted, and the degree of agreement between different voxel sizes was evaluated using the Bland and Altman method (p < 0.05). Results: All materials showed an increase in thickness from 5 to 10 and 20 µm (p < 0.05). When evaluating the interface voids, materials were similar at 5 µm (p > 0.05), while at 10 and 20 µm Biodentine showed the lowest percentage of voids (p < 0.05). A decrease in the interface voids was observed for MTA and IRM at 20 µm, while Biodentine showed differences among all voxel sizes (p < 0.05). The Bland-Altman plots for comparisons among voxel sizes showed the largest deviations when comparing images between 5 and 20 µm. Conclusions: Voxel size had an impact on the micro-CT evaluation of thickness and interface voids of endodontic materials. All cements exhibited an increase in thickness and a decrease in the void percentage as the voxel size increased, especially when evaluating images at 20 µm.

Malignant tumours mimicking periapical lesions: A report of three cases and literature review.

Apical periodontitis shows radiographic signs such as widening of the periodontal ligament and periapical radiolucency, which differ in extent depending on the stage of the lesion. However, other lesions can be associated with or coincidental to the apical region, representing developmental lesions and benign or malignant tumours. This article describes three cases of malignant tumours, a central mucoepidermoid carcinoma (CMEC), a chondroblast osteosarcoma and an osteosarcoma of the jaw (OSJ) that presented as periapical lesions. Endodontists must be aware of unsuccessful treatment, persistent pain, signs of paraesthesia, a rapid growth rate and delayed response to therapy associated with atypical features. Complementary examinations, such as biopsy and computed tomography, can allow the early diagnosis of malignant tumours, leading to a better prognosis and thus increased survival rates and improvement in quality of life.

How image-processing parameters can influence the assessment of dental materials using micro-CT.

PURPOSE: The aim of this study was to evaluate the influence of voxel size and different post-processing algorithms on the analysis of dental materials using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Root-end cavities were prepared in extracted maxillary premolars, filled with mineral trioxide aggregate (MTA), Biodentine, and Intermediate Restorative Material (IRM), and scanned using micro-CT. The volume and porosity of materials were evaluated and compared using voxel sizes of 5, 10, and 20 µm, as well as different software tools (post-processing algorithms). The CTAn or MeVisLab/Materialise 3-matic software package was used to perform volume and morphological analyses, and the CTAn or MeVisLab/Amira software was used to evaluate porosity. Data were analyzed using 1-way ANOVA and the Tukey test (P<0.05). RESULTS: Using MeVisLab/Materialise 3-matic, a consistent tendency was observed for volume to increase at larger voxel sizes. CTAn showed higher volumes for MTA and IRM at 20 µm. Using CTAn, porosity values decreased as voxel size increased, with statistically significant differences for all materials. MeVisLab/Amira showed a difference for MTA and IRM at 5 µm, and for Biodentine at 20 µm. Significant differences in volume and porosity were observed in all software packages for Biodentine across all voxel sizes. CONCLUSION: Some differences in volume and porosity were found according to voxel size, image-processing software, and the radiopacity of the material. Consistent protocols are needed for research evaluating dental materials.

A new cone-beam computed tomography-driven index for osteoporosis prediction.

OBJECTIVE: To verify whether mandibular cortical analyses accurately distinguish postmenopausal women with normal bone mineral density (BMD) from women with osteoporosis by means of a cone-beam computed tomography (CBCT)-driven composite osteoporosis index (three-dimensional mandibular osteoporosis index-3D MOI). MATERIAL AND METHODS: The comparison was performed between 52 women with normal BMD and 51 women with osteoporosis according to dual-energy X-ray absorptiometry (DXA) examination of the lumbar spine and hip. Mandibular cortical width (MCW) and cortical quality were evaluated on cross-sectional and panoramic reconstructed images. ANOVA, ROC curves and accuracy measurements were used for statistical analyses, as well as a predictive model combining the quantitative and qualitative analyses and age. RESULTS: All CBCT-driven measurements presented good to moderate intra- and interobserver agreements. MCW values were significantly lower in women with osteoporosis. Postmenopausal women with osteoporosis were 8 times more likely to have the cortex classified as C3, and 2.4 times more likely to have MCW thinner than 2.75 mm. The area under the ROC curve was 0.8 for the predictive model. CONCLUSIONS: The newly developed 3D MOI enables distinguishing women with osteoporosis from those with normal BMD with good sensitivity and specificity. CLINICAL RELEVANCE: Whenever a CBCT scan is performed for specific clinical indications, a 3D MOI may be performed to qualitatively and quantitatively assess the condition of the mandibular cortex. This may be surely helpful to assess the osteoporosis status in the ageing population and more specifically in peri- or postmenopausal women.

MicroCT assessment of bone microarchitecture in implant sites reconstructed with autogenous and xenogenous grafts: a pilot study.

PURPOSE: To assess bone microarchitecture in maxillary sites grafted with autogenous or xenogenous grafts as well as to demonstrate the usefulness of microCT in dental implant research. MATERIALS AND METHODS: Samples (n = 12) consisting of titanium fixation screws covered by at least 0.5-1 mm of human bone were obtained from 17 sites grafted with autogenous or xenogenous materials and prepared for microCT scanning and conventional histology. Bone histomorphometric parameters were evaluated in three distinct regions (graft region, transitional region, and native bone region). Three-dimensional (3D) bone-to-implant contact (BIC) calculation was performed using microCT data. Histological sections were used to calculate two-dimensional (2D) BIC percentages, which were compared with values obtained from 2D microCT images. RESULTS: Histomorphometric parameters varied according to the type of graft used, but sites reconstructed with autogenous bone showed higher mean values in general. In autograft samples, indices for parameters such as Tb.Th and Tb.Sp were significantly different when the native bone region was compared to the graft region. While a higher mean 3D BIC was found in the native bone region for both graft materials, significant BIC differences were absent when graft types were compared. The 2D BIC percentages obtained from histological and microCT images were similar. CONCLUSIONS: Autografts outperformed the xenogenous material used in this study concerning the histomorphometric parameters assessed. While graft type did not seem to influence 3D BIC, the native bone region showed the highest BIC percentages when compared to the other regions in both graft groups. In addition, 2D BIC ratios were similar regardless of graft material or image source (histological sections x microCT slices). Taken together, our findings suggest that microCT is an effective tool for 2D and 3D histomorphometric and BIC assessments in dental implant research.

Brazilian young dental practitioners' use and acceptance of digital radiographic examinations.

PURPOSE: The aim of this study was to investigate the use and acceptance of digital radiographic examinations by Brazilian dental practitioners in daily practice and to evaluate the advances that have occurred over the past 5 years. MATERIALS AND METHODS: Dental practitioners enrolled in extension courses at the Piracicaba Dental School, University of Campinas, Brazil, responded to a self-administered questionnaire in the years 2011 and 2015. They were asked about sociodemographic factors and their knowledge and use of digital radiographic examinations. Descriptive analysis was performed, as well as the chi-square and Fisher exact tests, with a significance level of 5% (α=0.05). RESULTS: A total of 181 participants responded to the questionnaire in the years 2011 and 2015. Most of the respondents worked in private practice, had graduated within the last 5 years, and were between 20 and 30 years old. In 2011, 55.6% of respondents reported having ever used digital radiographic examinations, while in 2015 this number increased significantly to 85.4% (p<.0001), out of which 71.4% preferred it to conventional images. Moreover, 21.4% of respondents reported having used digital radiographic examinations for more than 3 years. A significant increase in use of intraoral digital radiography (p=0.0316) was observed in 2015. In both years, image quality and high cost were indicated, respectively, as the main advantage and disadvantage of digital radiographic examinations. CONCLUSION: This study showed that digital radiology has become more common in Brazil over the past 5 years. Most of the Brazilian dental practitioners evaluated in 2015 used digital radiographic examinations.