CBCT-based assessment of root canal treatment using micro-CT reference images.

Purpose: This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling. Materials and Methods: Isthmus-containing mesial roots of mandibular molars (n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses (α=5%). Results: Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory. Conclusion: CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.

High doses of zoledronic acid induce differential effects on femur and jawbone microstructure.

OBJECTIVES: The aim of this study is to investigate the long-term effects on jaw and femur bone induced by oncologic doses of zoledronic acid in a young rat model. MATERIAL AND METHODS: Six 12-week-old male Wistar rats received zoledronic acid (0.6 mg/kg) and six control rats received saline solution in the same volume. Compounds were administered intraperitoneally in five doses every 28 days. Euthanasia was performed 150 days after therapy onset. After animal sacrifice, their mandibles and femurs were scanned ex vivo using a high-resolution (14 µm) micro-computed tomography. Morphometric bone parameters were calculated using CT-Analyzer (Bruker, Belgium) between the first and second mandibular molars and in the distal femur metaphysis and epiphysis. RESULTS: The treatment group as compared to the controls showed a significantly (p < .05) increased bone quantity (↑BV/TV, ↓Po[Tot], ↑Tb.Th), bone density (↑TMD, ↑BMD), and osteosclerosis of the trabecular bone (↓Tb.Sp, ↓Conn.Dn, ↓Tb.Pf, ↓SMI) in all anatomical sites. Bone remodeling suppression due to zoledronic acid treatment was more pronounced (p < .05) in the femoral metaphysis relative to the mandible and epiphysis. The exploratory linear discriminant analysis showed that for the mandible, it was mainly the bone quantity-related morphometric indices (BV/TV and Tb.Th), while for the femoral epiphysis and metaphysis, it was bone structure-related (Tb.Pf and Tb.N), which are of primary importance to study the treatment effect. CONCLUSION: High doses of bisphosphonates can differently affect the bone quantity, density, and structure in long bones and jawbones. In the metaphysis, bone changes were primarily concentrated in the region of the growth plate. Future studies may consider the use of bone morphometric indices to evaluate the effect of bisphosphonates.

A quantitative analysis of metal artifact reduction algorithm performance in volume correction with 3 CBCT devices.

OBJECTIVE: The aim of this study was to quantitatively assess the performance of metal artifact reduction (MAR) algorithms on the volume of metal cylinders, considering the influence of materials, positions, and fields of view (FOVs), by using 3 cone beam computed tomography (CBCT) devices (NewTom VGi evo, Picasso Trio, and ProMax 3-D Max). STUDY DESIGN: Nine phantoms containing cylinders of amalgam, copper-aluminum (CuAl) metal alloy, and titanium, combined in up to 3 positions, were scanned by using 2 different FOVs. MATLAB software was used to evaluate the differences between volumes before and after MAR application, and the possible interference of materials, positions, and FOVs. Wilcoxon's test and the Kruskal-Wallis test were used at a level of significance of 5%. RESULTS: In general, images containing amalgam and CuAl showed a significant difference in volume before and after MAR application. However, no significant difference after MAR was observed (P > .05) relative to positions and FOVs. MAR had an impact on the cylinder volumes only in the NewTom VGi evo and ProMax 3-D Max scanners. CONCLUSIONS: The performance of MAR algorithms in volume correction of metal objects is dependent on the materials and the CBCT unit.

Relationship between trabecular bone architecture and early dental implant failure in the posterior region of the mandible.

OBJECTIVE: To investigate the relationship between preoperative trabecular bone structure and implant outcome based on bone morphometric bone parameters from CBCT scans. MATERIALS AND METHODS: Twenty consecutive cases with early implant failure in the posterior region of the mandible were matched with 20 control patients with a successful implant osseointegration selected. All patients had taken a preoperative CBCT image according to a standardized acquisition protocol. On these CBCT scans, the trabecular bone of each implantation site was selected and segmented, after which 3D morphometric bone parameters were calculated and used in a cluster analysis to objectively differentiate trabecular bone patterns. Fisher's exact test was used to determine whether there is a significant association between trabecular pattern and implant outcome. RESULTS: A sparse, intermediate, and dense trabecular bone pattern was distinguished by cluster analysis. The relationship between the trabecular bone pattern and early implant failure was significant (z = 9.6; p < .05). Early implant failure was more likely to occur in the sparse bone types, while implant survival was associated with intermediate bone types. CONCLUSION: Prior to implant placement, attention should be given to extreme deviations in trabecular structure at the planned implant sites. Very sparse or very dense bone should be carefully evaluated at the potential implant site, while intermediate bone types seem favorable for implant survival.

Comparative evaluation of cone beam CT and micro-CT on blooming artifacts in human teeth filled with bioceramic sealers.

AIM: To assess blooming artifacts caused by root canal sealers in CBCT images compared with those that appeared in micro-CT scan images used as references. MATERIALS AND METHOD: Thirty freshly extracted human mandibular central incisors were used. Root canals were prepared with nickel titanium files with an ISO size 40/0.06 taper and filled with a single cone (40/0.06 taper) and three different sealers. The samples were divided into the following three groups with 10 roots each: (I) AH Plus sealer; (II) Sure Seal Root; and (III) Total BC sealer. Teeth were scanned with the same voxel sizes (0.2 mm) in different CBCT devices and the micro-CT images were acquired as reference images. RESULTS: Significantly different results in terms of blooming artifacts were detected between CBCT and micro-CT images, as well as among the CBCTs images. The canals filled with AH Plus sealer showed more blooming artifacts than those filled with bioceramic sealers (p < 0.05). Additionally, the worst blooming artifact was observed when the images were acquired with lower kilovoltage peak. CONCLUSION: The appearance of blooming artifacts is dependent on sealer and CBCT, and their effects are significantly worse than they are in micro-CT images. The differential effect of different sealers and distinct CBCT protocols should be further investigated to enable the use of bioceramic sealers without a significant impact on post-treatment imaging. CLINICAL RELEVANCE: Root canal sealers showed a different extent of blooming artifact in CBCT images. Hence, researchers and clinicians should be aware of these artifacts before conducting endodontic evaluations using CBCT images.

The performance of metal artifact reduction algorithms in cone beam computed tomography images considering the effects of materials, metal positions, and fields of view.

OBJECTIVE: The aim of this study was to assess the performance of 2 metal artifact reduction (MAR) algorithms in cone beam computed tomography (CBCT) imaging, considering different materials, metal positions, and fields of view (FOVs). STUDY DESIGN: Nine phantoms containing cylinders of amalgam, copper-aluminum (Cu-Al) alloy, and titanium were scanned by using Picasso Trio and ProMax 3D CBCT units with small and medium FOVs. Scans were made with and without MAR algorithms. The standard deviation (SD) of voxel gray values was measured in the neighborhood of the cylinders. Differences in SD were statistically evaluated for effects of MAR and the other parameters, with a significance level of 5%. RESULTS: Significant differences between images with MAR and those without MAR for both devices (P ≤ .0001) were observed. Amalgam showed the largest artifact expression, followed by Cu-Al and titanium. After correction, differences remained only in Picasso Trio images (P = .002). Considering positions, no significant difference in the performance of the MAR algorithm was observed in either device. Considering FOVs, significant differences were observed for ProMax 3D (P = .005), with less artifact expression in the medium FOV after MAR correction. CONCLUSIONS: MAR algorithms were effective for artifact reduction despite variation in performance according to device, FOV, and material properties. The position of the metal cylinder within the FOV had no significant effect.

Computer-based automatic classification of trabecular bone pattern can assist radiographic bone quality assessment at dental implant site.

OBJECTIVE:: To develop and validate an automated classification method that determines the trabecular bone pattern at implant site based on three-dimensional bone morphometric parameters derived from CBCT images. METHODS:: 25 human cadaver mandibles were scanned using CBCT clinical scanning protocol. Volumes-of-interest comprising only the trabecular bone of the posterior regions were selected and segmented for three-dimensional morphometric parameters calculation. Three experts rated all bone regions into one of the three trabecular pattern classes (sparse, intermediate and dense) to generate a reference classification. Morphometric parameters were used to automatically classify the trabecular pattern with linear discriminant analysis statistical model. The discriminatory power of each morphometric parameter for automatic classification was indicated and the accuracy compared to the reference classification. Repeated-measures analysis of variances were used to statistically compare morphometric indices between the three classes. Finally, the outcome of the automatic classification was evaluated against a subjective classification performed independently by four different observers. RESULTS:: The overall correct classification was 83% for quantity-, 86% for structure-related parameters and 84% for the parameters combined. Cross-validation showed a 79% model prediction accuracy. Bone volume fraction (BV/TV) had the most discriminatory power in the automatic classification. Trabecular bone patterns could be distinguished based on most morphometric parameters, except for trabecular thickness (Tb.Th) and degree of anisotropy (DA). The interobserver agreement between the subjective observers was fair (0.25), while the test-retest agreement was moderate (0.46). In comparison with the reference standard, the overall agreement was moderate (0.44). CONCLUSION:: Automatic classification performed better than subjective classification with a prediction model comprising structure- and quantity-related morphometric parameters. ADVANCES IN KNOWLEDGE:: Computer-aided trabecular bone pattern assessment based on morphometric parameters could assist objectivity in clinical bone quality classification.

Evaluation of Threshold Values for Root Canal Filling Voids in Micro-CT and Nano-CT Images.

While several materials and techniques have been used to assess the quality of root canal fillings in micro-CT images, the lack of standardization in scanning protocols has produced conflicting results. Hence, the aim of this study was to determine a cutoff voxel size value for the assessment of root canal filling voids in micro-CT and nano-CT images. Twenty freshly extracted mandibular central incisors were used. Root canals were prepared with nickel titanium files to an ISO size 40/0.06 taper and then filled with a single cone (40/0.06 taper) and AH Plus sealer. The teeth were scanned with different voxel sizes with either micro-CT (5.2, 8.1, 11.2, and 16.73 µm) or nano-CT (1.5 and 5.0 µm) equipment. Images were reconstructed and analyzed with the NRecon and CTAn software. Void proportion and void volume were calculated for each tooth in the apical, middle, and coronal thirds of the root canal. Kruskal-Wallis and post hoc Mann-Whitney U tests were performed with a significance level of 5%. In micro-CT images, significantly different results were detected among the tested voxel sizes for void proportion and void volume, whereas no such differences were found in nano-CT images (p > 0.05). Micro-CT images showed higher void numbers over the entire root length, with statistically significant differences between the voxel size of 16.73 µm and the other sizes (p < 0.05). The values of the different nano-CT voxel sizes did not significantly differ from those of the micro-CT (5.2, 8.1, and 11.2 µm), except for the voxel size of 16.73 µm (p < 0.05). All tested voxel sizes enabled the detection of root canal filling voids except for the voxel size of 16.73 µm. Bearing in mind the limitations of this study, it seems that a voxel size of 11.2 µm can be used as a reliable cutoff value for the assessment of root canal filling voids in micro-CT imaging.

DIMITRA paediatric skull phantoms: development of age-specific paediatric models for dentomaxillofacial radiology research.

OBJECTIVES: This report aims to describe the development of age-specific phantoms for use in paediatric dentomaxillofacial radiology research. These phantoms are denoted DIMITRA paediatric skull phantoms as these have been primarily developed and validated for the DIMITRA European research project (Dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks). METHODS: To create the DIMITRA paediatric phantoms, six human paediatric skulls with estimated ages ranging between 4 and 10 years- old were selected, protected with non-radiopaque tape and immersed in melted Mix-D soft tissue equivalent material, by means of a careful procedure (layer-by-layer). Mandibles were immersed separately and a Mix-D tongue model was also created. For validation purposes, the resulting paediatric phantoms were scanned using a cone-beam CT unit with different exposure parameter settings. RESULTS: Preliminary images deriving from all scans were evaluated by two dentomaxillofacial radiologists, to check for air bubbles, artefacts and inhomogeneities of the Mix-D and a potential effect on the visualization of the jaw bone. Only skulls presenting perfect alignment of Mix-D surrounding the bone surfaces with adequate and realistic soft tissue thickness density were accepted. CONCLUSIONS: The DIMITRA anthropomorphic phantoms can yield clinically equivalent images for optimization studies in dentomaxillofacial research. In addition, the layer-by-layer technique proved to be practical and reproducible, as long as recommendations are carefully followed.

Conservative management of large mandibular dentigerous cysts with a novel approach for follow up: Two case reports.

BACKGROUND: Dentigerous cysts are odontogenic cysts of the jaws accounting for approximately 24% of all epithelium-lined jaw cysts. Rarely, these cysts can become extremely large causing additional symptoms, while challenging treatment. This article represents a novel approach for radiological treatment follow up of large dentigerous cysts. MATERIAL AND METHODS: Dentigerous cysts were treated by marsupialization, using dedicated obturators and enucleation of the cyst afterwards. Teeth vitality in the lesion was regularly assessed by laser doppler flowmetry, follow-up of lesion regression was accomplished using semi-automatic radiographic analysis of bone healing quantification. RESULTS: Cystic marsupialization by means of the obturator resulted in a number of advantages compared to a conventional approach: lower risk of spontaneous fracture of the mandible, anatomical structure preservation, mandibular canal identification and preservation of tooth vitality as measured by intraoral laser doppler flowmetry. Notwithstanding that a 1-year follow-up panoramic image could not visualize a remnant bone defect nor cystic lesion recurrence, 3D-CBCT based semi-automated bone quantification could only demonstrate an increase of 46% of mineralized bone volume one year after surgery. Bone healing typically occurred starting from the periphery of the original lesion towards the inner core. CONCLUSIONS: The presently reported cystic marsupialization was useful as a preliminary treatment for subsequent enucleation. 3-D CBCT based objective quantification of the bone volume and healing can provide new insights in lesion healing in general and more particular in the outcome of specific diagnostic and therapeutic challenges.

Dislocation of a mandibular condyle in the middle cranial fossa, diagnosed 54 years after trauma.

Dislocation of the mandibular condyle into the middle cranial fossa is a rare complication of mandibular trauma. We report the remarkable case of a 63-year-old patient in whom trauma 54 years prior to consultation resulted in intrusion of the right mandibular condyle into the middle cranial fossa. The diagnosis was missed because of insufficient data provided by conventional radiographies. Failure of timely diagnosis and lack of appropriate treatment resulted in temporomandibular joint ankylosis with functional impairment, disturbance of mandibular growth and dentofacial asymmetry. We emphasize the need for careful radiological investigation in case of a suspected condylar fracture or dislocation, especially when the mechanism of injury is likely to facilitate condylar intrusion. The use of CT and MR-imaging is therefore advocated.

Micro-CT and nano-CT analysis of filling quality of three different endodontic sealers.

OBJECTIVES: To investigate voids in different root canal sealers using micro-CT and nano-CT, and to explore the feasibility of using nano-CT for quantitative analysis of sealer filling quality. METHODS: 30 extracted mandibular central incisors were randomly assigned into three groups according to the applied root canal sealers (Total BC Sealer, Sure Seal Root, AH Plus) by the single cone technique. Subsequently, micro-CT and nano-CT were performed to analyse the incidence rate of voids, void fraction, void volume and their distribution in each sample. RESULTS: Micro-CT evaluation showed no significant difference among sealers for the incidence rate of voids or void fraction in the whole filling materials (p > 0.05), whereas a significant difference was found between AH Plus and the other two sealers using nano-CT (p < 0.05). All three sealers presented less void volume in the apical third; however, higher void volumes were observed in the apical and coronal thirds in AH Plus using micro-CT (p < 0.05), while nano-CT results displayed higher void volume in AH Plus among all the sealers and regions (p < 0.05). CONCLUSIONS: Bioactive sealers showed higher root filling rate, lower incidence rate of voids, void fraction and void volume than AH Plus under nano-CT analysis, when round root canals were treated by the single cone technique. The disparate results suggest that the higher resolution of nano-CT have a greater ability of distinguishing internal porosity, and therefore suggesting the potential use of nano-CT in quantitative analysis of filling quality of sealers.

Validation of a novel imaging approach using multi-slice CT and cone-beam CT to follow-up on condylar remodeling after bimaxillary surgery.

The main goal of this study was to introduce a novel three-dimensional procedure to objectively quantify both inner and outer condylar remodelling on preoperative multi-slice computed tomography (MSCT) and postoperative cone-beam computed tomography (CBCT) images. Second, the reliability and accuracy of this condylar volume quantification method was assessed. The mandibles of 20 patients (11 female and 9 male) who underwent bimaxillary surgery were semi-automatically extracted from MSCT/CBCT scans and rendered in 3D. The resulting condyles were spatially matched by using an anatomical landmark-based registration procedure. A standardized sphere was created around each condyle, and the condylar bone volume within this selected region of interest was automatically calculated. To investigate the reproducibility of the method, inter- and intra-observer reliability was calculated for assessments made by two experienced radiologists twice five months apart in a set of ten randomly selected patients. To test the accuracy of the bone segmentation, the inner and outer bone structures of one dry mandible, scanned according to the clinical set-up, were compared with the gold standard, micro-CT. Thirty-eight condyles showed a significant (P<0.05) mean bone volume decrease of 26.4%±11.4% (502.9 mm3±268.1 mm3). No significant effects of side, sex or age were found. Good to excellent (ICC>0.6) intra- and inter-observer reliability was observed for both MSCT and CBCT. Moreover, the bone segmentation accuracy was less than one voxel (0.4 mm) for MSCT (0.3 mm±0.2 mm) and CBCT (0.4 mm±0.3 mm), thus indicating the clinical potential of this method for objective follow-up in pathological condylar resorption.

Assessment of Volumetric Distortion Artifact in Filled Root Canals Using Different Cone-beam Computed Tomographic Devices.

INTRODUCTION: Artifacts in cone-beam computed tomographic (CBCT) imaging may compromise radiodiagnosis. Obturation materials for endodontic treatment may present with variable material density and thus also cause distinct artifact expression. The aim of this study was to assess the volume distortion artifact of root canal sealers using CBCT devices and micro-CT imaging as a reference. METHODS: Thirty single-root mandibular central incisors were used for this study. Teeth were prepared with EndoSequence rotary nickel-titanium files (Brasseler USA, Savannah, GA) and divided into 3 groups. Canals were obturated with gutta-percha and AH Plus root canal sealer (Dentsply Maillefer, Ballaigues, Switzerland) using single-cone filling techniques. Each tooth was scanned with different CBCT devices (ie, Promax 3D Max [Planmeca Inc, Roselle, IL], NewTom VGi evo [NewTom, Verona, Italy], and 3D Accuitomo 170 [J Morita, Kyoto, Japan]) with the same voxel size (0.2 mm3) and compared with micro-CT imaging as a reference standard. RESULTS: The results showed a significant difference in terms of volume distortion between micro-CT and CBCT images (P < .05). There were also significant differences among CBCT devices. Promax 3D Max measurements showed significantly larger root canal volumes than the other CBCT machines (P < .05). However, NewTom VGi evo and 3D Accuitomo 170 showed similar results without any significant difference (P > .05). CONCLUSIONS: CBCT devices showed more volumetric distortion artifact than micro-CT imaging. The volume was variable for different CBCT devices while scanning at the same voxel size. However, to assess the effect of sealer materials on CBCT imaging, further studies should be conducted for different sealers.

Quantitative evaluation of metal artifacts using different CBCT devices, high-density materials and field of views.

OBJECTIVE: To objectively compare the influence of different cone-beam computed tomography (CBCT) devices, high-density materials and field of views (FOVs) on metal artifact expression. MATERIAL AND METHODS: For this in vitro study, three customized acrylic resin phantoms containing high-density materials cylinders: titanium, copper-aluminum alloy and amalgam were scanned on three CBCT devices using high-resolution protocols, same voxel size (0.2 mm) and different FOVs. After fully automatic segmentation and image registration, the same region of interest was defined for the small and medium FOVs. The difference between the segmented and the real volume of the metal cylinders was assessed. Moreover for each segmented slice, the area difference between the segmented and the real axial section was determined. The artifacts on the background were measured as normalizing standard deviation of voxel values in the vicinity of the cylinder, in three different distances. RESULTS: Considerable differences were observed in volume measurements for all CBCTs devices and materials for both FOV sizes (up to 67%). The slice per slice area analysis indicated higher artifacts at the edges of the metal cylinder. Within the materials, amalgam and titanium had, respectively, the worst and best artifact expression in all the CBCT devices. Standard deviation values varied differently between the three distances in each device. CONCLUSION: Our in vitro study showed that different CBCT devices, high-density materials and FOV should be considered while evaluating CBCT images. More carefully, diagnosis conclusions should be drawn in images containing amalgam and copper-aluminum alloy.

Report of Neuropathic Pain After Dental Implant Placement: A Case Series.

PURPOSE: To report on a cohort of patients referred to a tertiary center because of neuropathic pain after dental implant placement. MATERIALS AND METHODS: This retrospective study of pain after dental implant placement involved a minimum follow-up of 12 months after the initial diagnosis of neuropathic pain or persistent, uncontrolled postoperative pain at the Department of Oral and Maxillofacial Surgery, Leuven University, Leuven, Belgium, from January 2013 to June 2014. RESULTS: Following clinical and radiologic examination, the cause of pain was established in 17 of 26 patients, while the cause was unknown in 9 of 26 patients. Regular implants were placed in the mandibles of 18 patients; in the remaining 8 patients, 6 received regular implants and 2 received a zygoma implant in the maxilla. Surgical management alone brought relief to 2 patients, surgical and pharmacologic management did so for 12 patients, and pharmacologic management alone brought relief for 10 patients. CONCLUSIONS: Early removal of an at-risk implant seems justified, preferably within 48 hours after placement. No treatment, either surgical or medical, seems to cure neuropathic pain, but amitriptyline appears to be associated with consistent improvement in symptoms.

Accuracy and reliability of different cone beam computed tomography (CBCT) devices for structural analysis of alveolar bone in comparison with multislice CT and micro-CT.

OBJECTIVE: The aim of this study was to assess whether cone beam computed tomography (CBCT) may be used for clinically reliable alveolar bone quality assessment in comparison to its clinical alternatives, multislice computed tomography and the gold standard (micro-CT). MATERIALS AND METHODS: Six dentate mandibular bone samples were scanned with seven CBCT devices (ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170, Carestream 9300, Scanora 3D, I-CAT Next generation), one micro-CT scanner (SkyScan 1174) and one MSCT machine (Somatom Definition Flash) using two protocols (standard and high-resolution). MSCT and CBCT images were automatically spatially aligned on the micro-CT scan of the corresponding sample. A volume of interest was manually delineated on the micro-CT image and overlaid on the other scanning devices. Alveolar bone structures were automatically extracted using the adaptive thresholding algorithm. Based on the resulting binary images, an automatic 3D morphometric quantification was performed in a CT-Analyser (Bruker, Kontich, Belgium). The reliability and measurement errors were calculated for each modality compared to the gold standard micro-CT. RESULTS: Both MSCT and CBCT were associated with a clinically and statistically (P <0.05) significant measurement error. Bone quantity-related morphometric indices (bone volume fraction 8.41% min to 17.90% max, bone surface density -0.47 mm-1 min to 0.16 mm-1 max and trabecular thickness 0.15 mm min to 0.31 mm max) were significantly (P <0.05) overestimated, resulting in significantly (P <0.05) closer trabecular pores (total porosity percentage -8.41% min to -17.90% max and fractal dimension 0.08 min to 0.17 max) in all scanners compared to micro-CT. However, the structural pattern of the alveolar bone remained similar compared to that of the micro-CT for the ProMax 3D Max, NewTom GiANO, Cranex 3D, 3D Accuitomo 170 and Carestream 9300. On the other hand, the Scanora 3D, i-CAT Next Generation, standard and high-resolution MSCT displayed an overrated bone quantity and aberrant structural pattern compared to other scanning devices. The calculation of morphometric indices had an overall high reliability (intraclass correlation coefficient [ICC] 0.62 min to 0.99 max), except for the i-CAT Next Generation CBCT (ICC 0.26 min to 0.86 max) and standard resolution MSCT (ICC 0.10 min to 0.62 max). CONCLUSIONS: This study demonstrated that most CBCT machines may be able to quantitatively assess alveolar bone quality, with a level of accuracy and reliability that approaches micro-CT. One may therefore propose to extrapolate this to clinical CBCT imaging, certainly when there is a need for implant rehabilitation in dentate jaw bones. Conflict-of-interest statement: There is no conflict of interest to declare. FUNDING: Fellowship support was received from Research Foundation Flanders (FWO) from the Belgian government and from the Coordination for the Improvement of Higher Education Personnel (CAPES) programme, Science without Borders, from the Brazilian government.

Quantification of bone quality using different cone beam computed tomography devices: Accuracy assessment for edentulous human mandibles.

PURPOSE: To determine the accuracy of the latest cone beam computed tomography (CBCT) machines in comparison to multi-slice computer tomography (MSCT) and micro computed tomography (micro-CT) for objectively assessing trabecular and cortical bone quality prior to implant placement. MATERIALS AND METHODS: Eight edentulous human mandibular bone samples were scanned with seven CBCT scanners (3D Accuitomo 170, i-CAT Next Generation, ProMax 3D Max, Scanora 3D, Cranex 3D, Newtom GiANO and Carestream 9300) and one MSCT system (Somatom Definition Flash) using the clinical exposure protocol with the highest resolution. Micro-CT (SkyScan 1174) images served as a gold standard. A volume of interest (VOI) comprising trabecular and cortical bone only was delineated on the micro-CT. After spatial alignment of all scan types, micro-CT VOIs were overlaid on the CBCT and MSCT images. Segmentation was applied and morphometric parameters were calculated for each scanner. CBCT and MSCT morphometric parameters were compared with micro-CT using mixed-effect models. Intraclass correlation analysis was used to grade the accuracy of each scanner in assessing trabecular and cortical quality in comparison with the gold standard. Bone structure patterns of each scanner were compared with micro-CT in 2D and 3D to facilitate the interpretation of the morphometric analysis. RESULTS: Morphometric analysis showed an overestimation of the cortical and trabecular bone quantity during CBCT and MSCT evaluation compared to the gold standard micro-CT. The trabecular thickness (Tb.Th) was found to be significantly (P < 0.05) different and the smallest overestimation was found for the ProMax 3D Max (180 µm), followed by the 3D Accuitomo 170 (200 µm), Carestream 9300 (220 µm), Newtom GiANO (240 µm), Cranex 3D (280 µm), Scanora 3D (300 µm), high resolution MSCT (310 µm), i-CAT Next Generation (430 µm) and standard resolution MSCT (510 µm). The underestimation of the cortical thickness (Ct.Th) in ProMax 3D Max (-10 µm), the overestimation in Newtom GiANO (10 µm) and the high resolution MSCT (10 µm) were neglible. However, a significant overestimation (P < 0.05) was found for 3D Accuitomo 170 (110 µm), Scanora 3D (140 µm), standard resolution MSCT (150 µm), Carestream 9300 (190 µm), Cranex 3D (190 µm) and i-CAT Next Generation (230 µm). Comparison of the 2D network and 3D surface distance confirmed the overestimation in bone quantity, but only demonstrated a deviant trabecular network for the i-CAT Next Generation and the standard resolution MSCT. Intraclass correlation coefficients (ICCs) showed a significant (P < 0.05) high intra-observer reliability (ICC > 0.70) in morphometric evaluation between micro-CT and commercially available CBCT scanners (3D Accuitomo 170, Newtom GiANO and ProMax 3D Max). The ICC for Tb.Th and Ct.Th were 0.72 and 0.98 (3D Accuitomo 170), 0.71 and 0.96 (Newtom GiANO), and 0.87 and 0.92 (ProMax 3D Max), respectively. CONCLUSIONS: High resolution CBCT offers a clinical alternative to MSCT to objectively determine the bone quality prior to implant placement. However, not all tested CBCT machines have sufficient resolution to accurately depict the trabecular network or cortical bone. Conflict-of-interest statement: There is no conflict of interest to declare. FUNDING: Fellowship support came from Research Foundation Flanders (FWO) from the Belgian government, and Coordination for the Improvement of Higher Education Personnel (CAPES) program and Science without borders from the Brazilian government.

Presurgical CBCT assessment of maxillary neurovascularization in relation to maxillary sinus augmentation procedures and posterior implant placement.

PURPOSE: To provide more information to clinicians planning sinus grafting and maxillofacial surgical interventions, the present study evaluated the prevalence, diameter and location of the superior alveolar canals (SAC) using CBCT images. METHODS: The maxillary sinus CBCT scans (i-CAT Classic(®), ISI, USA) of 100 adult patients (67 women and 33 men) aged 20-79 years [mean (SD) 40 (15)] were examined. A dentomaxillofacial radiologist observed the SAC based on CBCT image data and more specifically the parasagittal views to assess SAC's diameter and location. RESULTS: The anterior and posterior SAC, double ASAC, intraosseous anastomoses and the extension of the anterior SAC to the piriform aperture were observed in 100, 73, 24.5, 38.5 and 84 % of the cases, respectively. The anastomosis was located between canine and first premolar in 43 % of the cases. The SAC diameters were in 80 % of the cases ≤1 mm, remaining canals had a diameter between 1 and 2 mm. The distance of the SAC to the alveolar crest ranged between 2.42 and 44.6 mm. The anterior SAC was more prevalent in the upper (53 %) and middle (44 %) thirds of the maxillary sinus, while the posterior SAC was more prevalent in the middle (36 %) and lower thirds (64 %). The distance was significantly bigger in men in some tooth positions. CONCLUSIONS: Based on the present findings, one-fifth of the patients may have a diameter of the SAC >1 mm, large enough to cause bleeding and/or paraesthesia. CBCT imaging may assist surgeons to plan grafting and osteotomy procedures, while avoiding these neurovascular structures.

Estudo dos canais alveolares superiores e do canal infra-orbital por meio da tomografia computadorizada de feixe cônico / Study of the superior alveolar canals and infraorbital canal using cone beam computed tomography

Para oferecer mais informações aos cirurgiões no planejamento de intervenções cirúrgicas maxilofaciais, o presente estudo teve como objetivo avaliar a presença, localização e tamanho dos canais alveolares superiores (CAS), anterior (CASA) e posterior (CASP), canal infra-orbital (CI) e forame infra-orbital (FI) em imagens de tomografia computadorizada de feixe cônico (TCFC) de 100 pacientes adultos (≥ 20 anos), obtidas pelo aparelho i-CAT Classic®. Um examinador calibrado observou a presença dos CAS, CI e FI bilateralmente. Quando presentes, eram medidos comprimento (parte descendente, parte do assoalho da órbita e total), largura e altura do CI; altura, largura e distância ao rebordo inferior da órbita (RIO) do FI; distância da borda inferior dos CAS a crista do rebordo alveolar em 5 regiões: canino (CAN), primeiro pré-molar (1PM), segundo pré-molar (2PM), primeiro molar (1M) e segundo molar (2M); e os diâmetros dos CAS. Foram também observados a localização dos CAS em relação ao seio maxilar e a presença de reparos anatômicos como canal duplo/múltiplo, anastomose intra-óssea e extensão do CASA para a abertura piriforme. Associações entre homens e mulheres, lados direito e esquerdo e regiões foram investigadas para todas as medidas e visibilidade, utilizando separadamente os métodos estatísticos. A presença do CI e FI foi de 100%. A visibilidade do CASA/CASP foi de: 99%/0% (CAN), 99%/21% (1PM), 89%/41% (2PM), 46%/44% (1M) e 7%/61% (2M). As médias dos comprimentos da parte descendente, da parte do assoalho da órbita e total do CI foram de 8,82mm, 19,44mm e 28,35mm, respectivamente. Altura e largura médias do CI foram, respectivamente, 2,08mm e 3,91mm. As médias da altura, largura e distância ao RIO do FI foram: 4,43mm, 5,18mm e 7,52mm, respectivamente. As distâncias médias do CASA ao rebordo alveolar foram: 18,54mm (CAN), 25,47mm (1PM), 28,43mm (2PM), 30,78mm (1M) e 33,21mm (2M); e do CASP: 22,3mm (1PM), 17,65mm (2PM), 15,34mm (1M) e 16,87mm (2M)...

To provide more information to clinicians in planning maxillofacial surgical interventions, the present study evaluated the presence, location and size of the superior alveolar canals (SAC), anterior (ASAC) and posterior (PSAC), infraorbital canal (IC) and infra-orbital foramen (IF) in cone beam computed tomography (CBCT) of 100 adult patients (≥ 20 years old), obtained by i-CAT Classic®. One calibrated examiner observed SAC, IC and IF presence, bilaterally. When present, were measured: length (descending part, orbital floor part and total), width and height of the IC, height, width and distance from the IF to the inferior orbital rim (IOR), distance from the lower border of SAC to the alveolar crest in 5 regions: canine (CAN), first premolar (1PM), second premolar (2PM), first molar (1M) and second molar (2M); and the diameters of SAC. It was also observed the location of SAC in relation to the maxillary sinus floor and the presence of anatomical landmarks such as doble/multiple canal, intraosseous anastomosis and ASAC extension to the piriform aperture. Associations between men and women, right and left sides and regions were investigated for all measurements and presence using statistical methods separately. The presence of the IC and IF was 100%. The presence of ASAC/PSAC was: 99%/0% (CAN), 99%/21% (1PM), 89%/41% (2PM), 46%/44% (1M) e 7%/61% (2M). The mean lengths of the IC descending part, IC orbital floor part and total lenght of the IC were 8.82mm, 19.44mm and 28.35mm, respectively. The mean height and width of the IC were, respectively, 2.08mm and 3.91mm. The mean height, width and distance to the IOR of IF were: 4.43mm, 5.18mm and 7.52mm, respectively. The mean distances of ASAC to the alveolar crest were: 18.54mm (CAN), 25.47mm (1PM), 28.43mm (2PM), 30.78mm (1M) and 33.21mm (2M); and of PSAC: 22.3mm (1PM), 17.65mm (2PM) 15.34mm (1M) and 16.87mm (2M). The mean diameters of ASAC and PSAC were 0.90mm and 0.83mm, respectively, and that, 77...