Filling quality of several obturation techniques in the presence of apically separated instruments: A Micro‐CT study

2020 ◽  
Author(s):  
Sevinç Aktemur Türker ◽  
Emel Uzunoğlu‐Özyürek ◽  
Sena Kaşikçi ◽  
Melike Öndeş ◽  
Ferhat Geneci ◽  
...  
Keyword(s):  
Micro Ct

scholarly journals ON THE ROLE OF HISTOMORPHOMETRIC (STEREOLOGICAL) MICROSTRUCTURE PARAMETERS IN THE PREDICTION OF VERTEBRAE COMPRESSION STRENGTH

2019 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
Leszek Karol Wojnar ◽  
Aneta Gądek-Moszczak ◽  
Jacek Pietraszek
Keyword(s):  
Compression Strength ◽  
Correlation Coefficients ◽  
Diagnostic Techniques ◽  
Micro Ct ◽  
Compression Tests ◽  
Mineral Density ◽  
3D Images ◽  
Microstructure Parameters

The well-documented relation between bone mineral density (BMD) and bone compression strength constitutes the basis for osteoporosis diagnostics and the assessment of fracture risk. Simultaneously, this relation demonstrates a considerable scatter of results as bones of identical mineral density may have significantly different properties. The experimentally confirmed theorem that two materials or tissues of identical microstructure have identical properties leads to the evaluation of various quantitative stereological parameters (also referred to in biomedicine as histomorphology). These parameters, obtained from analysis of 2D or 3D images, have been used in numerous attempts to explain changes in bone strength. Although numerous correlation dependencies, often with high correlation coefficients, were evaluated, we do not know which parameters are worth evaluating, and there is no physical interpretation of these relations. An extended statistical analysis was accomplished on the basis of analysis of 3D images from 23 lumbar (L3) vertebrae scanned with micro-CT and the results of subsequent compression tests. A new parameter called SDF (structure destruction factor) was proposed in order to characterise the quality of 3D trabecular structures, and its significance was demonstrated. The final correlation function, which uses only three stereological parameters, made it possible to predict compression strength with considerable precision. The estimated values correlated very well with the apparent values (correlation coefficient r=0.96). Finally, the stereological parameters most suitable for characterisation of bone compression strength were chosen and a mechanism responsible for the changes in mechanical properties was proposed. The results obtained defined the necessary improvements in diagnostic techniques that would allow for more efficient quantitative microstructure evaluation and guidelines on how to improve treatment of patients with weakened bones.

scholarly journals Effect of BMP-2 with Microfracture on Osteochondral Defect in a Rabbits Talus

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0015
Author(s):  
Le Hoang Nam Dang ◽  
Kwang-Bok Lee
Keyword(s):  
Bone Regeneration ◽  
Subchondral Bone ◽  
Collagen Type ◽  
Osteochondral Defect ◽  
Border Zone ◽  
Micro Ct ◽  
Full Thickness ◽  
Group I ◽  
Defect Repair

Category: Ankle, Basic Sciences/Biologics Introduction/Purpose: Microfracture is a technically safe, simple and cost-effective treatment option for osteochondral defect of the talus. However, fibrous tissue and fibrocartilage represent the predominant repairing tissues derived from these procedures and these tissues types do not exhibit the mechanical properties of native hyaline cartilage, long time for cartilage reconstruction and long-term failure results. Bone morphogenetic protein-2 (BMP-2) has been shown to stimulate matrix synthesis and increase in synthesis of cartilage-specific collagen type IIB thereby enhance regeneration of articular cartilage in vitro. The purpose of this study is to evaluate the treatment ability of combining BMP-2 with microfracture on osteochondral defect in rabbit talus. Methods: Full-thickness chondral defects (3 x 3 x 2 mm) was created in the center talus dome. Twenty four male white New Zealand rabbits were divided into four groups of 6 animals into each group dependent on treatment method; Group I (control, no treatment), II (microfracture only), III (10 µL rhBMP-2 treatment), IV (microfracture combine with 10 µL rhBMP-2 treatment). The animals were sacrificed at 2, 4, 6 weeks post operatively. The macroscopic assessment of the repaired tissue was evaluated using the International Cartilage Repair Society (ICRS) Macroscopic Score, which considers the degree of defect repair, the integration to the border zone, and the macroscopic appearance. Subchondral bone regeneration on defect was evaluated by micro-CT scan and the histological findings were scored by using a modified version of the established scoring system for osteochondral repair described by Wakitani, immunohistochemical staining was used for analysis of collagen type I and II. Results: : Excessive bone formation that originated from the subchondral bone region was not observed in any sample. Micro-CT shows higher subchondral bone regeneration on defect in group III, IV than group I, II at 4 and 6 weeks, respectively. According to macroscopic and histological results, group V shows higher quality of cartilage and faster cartilage regeneration compare with another group. In immunohistochemical analysis, group IV shows stronger positive staining for collagen type II in the area of the defect. Conclusion: These findings indicate that the combination BMP-2 with microfracture is effective at accelerating and improving quality of full-thickness cartilage defect repair in a rabbit talus model.

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

2017 ◽  
Vol 46 (8) ◽  
pp. 20170223 ◽  
Author(s):  
Yan Huang ◽  
Berkan Celikten ◽  
Karla de Faria Vasconcelos ◽  
Laura Ferreira Pinheiro Nicolielo ◽  
Nicholas Lippiatt ◽  
...  
Keyword(s):  
Micro Ct ◽  
Ct Analysis ◽  
Endodontic Sealers

Root canal filling quality of mandibular molars with EndoSequence BC and AH Plus sealers: A micro‐ CT study

2019 ◽  
Vol 46 (1) ◽  
pp. 82-87 ◽  
Author(s):  
Rafael Nigri Roizenblit ◽  
Fabiola Ormiga Soares ◽  
Ricardo Tadeu Lopes ◽  
Bernardo Camargo Santos ◽  
Heloisa Gusman
Keyword(s):  
Root Canal ◽  
Micro Ct ◽  
Root Canal Filling ◽  
Mandibular Molars ◽  
Ah Plus

Rock compressibility from microcomputed tomography images: Controls on digital rock simulations

Geophysics ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. WA127-WA139 ◽  
Author(s):  
Nishank Saxena ◽  
Ronny Hofmann ◽  
Amie Hows ◽  
Erik H. Saenger ◽  
Luca Duranti ◽  
...  
Keyword(s):  
Microcomputed Tomography ◽  
Image Resolution ◽  
Production Performance ◽  
Reservoir Rock ◽  
Micro Ct ◽  
Sandstone Sample ◽  
Digital Rock ◽  
Relative Contribution ◽  
Rock Compressibility

Rock compressibility is a major control of reservoir compaction, yet only limited core measurements are available to constrain estimates. Improved analytical and computational estimates of rock compressibility of reservoir rock can improve forecasts of reservoir production performance and the geomechanical integrity of compacting reservoirs. The fast-evolving digital rock technology can potentially overcome the need for simplification of pores (e.g., ellipsoids) to estimate rock compressibility as the computations are performed on an actual pore-scale image acquired using 3D microcomputed tomography (micro-CT). However, the computed compressibility using a digital image is impacted by numerous factors, including imaging conditions, image segmentation, constituent properties, choice of numerical simulator, rock field of view, how well the grain contacts are resolved in an image, and the treatment of grain-to-grain contacts. We have analyzed these factors and quantify their relative contribution to the rock moduli computed using micro-CT images of six rocks: a Fontainebleau sandstone sample, two Berea sandstone samples, a Castelgate sandstone sample, a grain pack, and a reservoir rock. We find that image-computed rock moduli are considerably stiffer than those inferred using laboratory-measured ultrasonic velocities. This disagreement cannot be solely explained by any one of the many controls when considered in isolation, but it can be ranked by their relative contribution to the overall rock compressibility. Among these factors, the image resolution generally has the largest impact on the quality of image-derived compressibility. For elasticity simulations, the quality of an image resolution is controlled by the ratio of the contact length and image voxel size. Images of poor resolution overestimate contact lengths, resulting in stiffer simulation results.

scholarly journals Quantitative analysis of metal artefacts of dental implant in CBCT image by correlation analysis to micro-CT: A microstructural study

2020 ◽  
pp. 20200365
Author(s):  
Chang-Ki Min ◽  
Kyoung-A Kim
Keyword(s):  
Correlation Analysis ◽  
Dental Implant ◽  
Alpha Angle ◽  
Correlation Coefficients ◽  
Micro Ct ◽  
Spearman Correlation ◽  
Microstructural Parameters ◽  
Metal Artefacts ◽  
Cbct Image

Objectives: Quantification of dental implant metal artefacts in CBCT images using correlation analysis of trabecular microstructural parameters from CBCT and micro-CT, and analysis of the effect of varying the angular position of the subject. Methods: Polyurethane synthetic bone blocks were first scanned without implants by micro-CT and CBCT. Two dental implants were then placed parallel in the bone blocks and these specimens were scanned by CBCT with different alpha angles. Three volumes of interest (VOI) were set for further analysis. Six microstructural parameters were measured: trabecular thickness (TbTh), trabecular spacing (ThSp), bone volume per total volume (BV/TV), bone surface per total volume (BS/TV), connectivity density (CD) and fractal dimension (FD). Micro-CT measurements were used as a gold standard for CBCT. Spearman correlation coefficients for each microstructural parameter from CBCT and micro-CT were calculated and compared using Steiger’s Z test. Results: Without the implants, in VOI1, the Spearman correlation coefficients of TbTh, TbSp, BV/TV, BS/TV, CD and FD were 0.599, 0.76, 0.552, 0.566, 0.664 and 0.607, respectively. With the implants, the correlation coefficients decreased sharply in VOI1. As the alpha angle increased from zero to 90°, the correlation coefficients increased and became significant. Similar results appeared in VOI2. In contrast, in VOI3, the correlation coefficient decreased as the alpha angle increased. Conclusions: Metal artefacts were successfully quantified using microstructural parameters in terms of the image quality of the CBCT. Changes in alpha angle affected the quality of the CBCT image.

scholarly journals IDH2-Deficient Mice Develop Spinal Deformities With Aging

2018 ◽  
pp. 487-494 ◽  
Author(s):  
U. CHAE ◽  
N.-R. PARK ◽  
E. S. KIM ◽  
J.-Y. CHOI ◽  
M. YIM ◽  
...  
Keyword(s):  
Animal Model ◽  
Morphological Analysis ◽  
Histological Analysis ◽  
Critical Role ◽  
Spinal Deformities ◽  
Micro Ct ◽  
Wild Type ◽  
Isocitrate Dehydrogenase 2 ◽  
Deficient Mice

Spinal deformities such as scoliosis and kyphosis are incurable, and can lead to decreased physical function, pain, and reduced quality of life. Despite much effort, no clear therapies for the treatment of these conditions have been found. Therefore, the development of an animal model for spinal deformity would be extremely valuable to our understanding of vertebral diseases. In this study, we demonstrate that mice deficient in the mitochondrial enzyme isocitrate dehydrogenase 2 (IDH2) develop spinal deformities with aging. We use morphological analysis as well as radiographic and micro-CT imaging of IDH2-deficient mice to characterize these deformities. Histological analysis showed increased abnormalities in IDH2-deficient mice compared to wild type mice. Taken together, the results suggest that IDH2 plays a critical role in maintaining the spinal structure by affecting the homeostatic balance between osteoclasts and osteoblasts. This indicates that IDH2 might be a potent target for the development of therapies for spinal deformities. Our findings also provide a novel animal model for vertebral disease research.

scholarly journals Application of core X-ray microtomography in oilfield geology

Georesursy ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 34-43
Author(s):  
Andrey Ponomarev ◽  
Mikhail Zavatsky ◽  
Tatiana Nurullina ◽  
Marsel Kadyrov ◽  
Kirill Galinsky ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Source Rocks ◽  
Micro Ct ◽  
Practical Application ◽  
X Ray ◽  
Current State ◽  
Digital Core ◽  
State Of Research ◽  
Oil Source

The article presents studies devoted to the practical application of computer X-ray microtomography (micro-CT) in oilfield geology. In particular, the authors give results of using the method for sample defectoscopy before petrophysical studies in order to improve the quality of analyzes. The paper includes an example of assessing the depth of core plugging with drilling fluid; assessing the mineral composition by micro-CT; experimental core studies when modeling the thermal effect on the oil source rocks of the Bazhenov formation. The authors also examine the current state of research in the field of digital petrophysics or digital core. The study is aimed at introducing the micro-CT method into the oilfield process.

scholarly journals Marginal gaps and internal voids after root-end filling using three calcium silicate-based materials: A Micro-CT analysis

2021 ◽  
Vol 32 (4) ◽  
pp. 1-7
Author(s):  
Alexander Pompermayer Jardine ◽  
Ketsia Fernanda Váz Rosa ◽  
Felipe Barros Matoso ◽  
Ramiro Martins Quintana ◽  
Renata Grazziotin-Soares ◽  
...  
Keyword(s):  
Root Canal ◽  
Calcium Silicate ◽  
Statistical Difference ◽  
Root Canal Treatment ◽  
Ct Scans ◽  
Micro Ct ◽  
Air Entrapment ◽  
Cavity Preparation ◽  
Ct Analysis

Abstract This study evaluated the 3D quality of root-end filling, assessing the presence (volume and percentage) of marginal gaps and internal voids formed after retro-filling with three calcium silicate-based materials: MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, France) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Florida, US). Thirty human, extracted, single rooted teeth were used. Orthograde root canal treatment, root resection (3mm shorter than the apex) and retrograde cavity preparation with ultrasonic tips were performed. Teeth were divided into 3 groups (n =10 each) following a stratified randomization according to the initial volume of the root-end cavity. After retrofilling, samples were stored for 7 days. Then, two rounds of micro-CT scans were performed: soon after root-end preparation (with the cavity still empty) and 7 days after root-end filling. Marginal gaps, internal voids volume (mm3 and %), as well as, the overall defects (sum of gaps and voids) were evaluated. Statistics compared the three groups in relation to those defects. There was not statistical difference between groups regarding the marginal gaps (P≥ 0.05), the internal voids (P≥ 0.05), and the overall defects (P≥ 0.05). Median (mm3) and % of overall air-entrapment defects (gaps and/or voids) was: 0.004mm3 and 1.749% for MTA Angelus, 0.018mm3 and 6.660% for Biodentine, and 0.012mm3 and 4.079% for Neo MTA Plus. All materials had gaps and/or voids. No differences were found between MTA Angelus, Biodentine and Neo MTA Plus.

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