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1.
Braz. j. oral sci ; 20: e210432, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1254269

RESUMO

Aim: The aim of this study was to evaluate, by micro-computed tomography (micro-CT) analysis, the remaining filling material during endodontic retreatment performed with Protaper retreatment without solvent. Methods: Forty mandibular molars were divided into two groups (n = 20) according to the sealer used in the obturation: the bioceramic TotalFill BC (TF) or the resin-based AH Plus (AHP). The specimens were scanned before instrumentation, after obturation and after filling removal. Only the mesial roots were analysed. The filling volumes and the remaining filling material were calculated in the entire root canal and in the cervical, middle and apical thirds. Results: The volume of obturation and the volume of remaining filling material in the entire root canal and in the cervical, middle and apical thirds of the canal between the groups were not statistically different (independent t-test, p > 0.05). In the AHP group, there was a higher percentage of remaining filling material in the middle third than in the cervical third (p < 0.05). Conclusion: The filling material could not be entirely removed from any specimen


Assuntos
Materiais Restauradores do Canal Radicular , Retratamento , Microtomografia por Raio-X , Dente Molar
2.
J Contemp Dent Pract ; 22(6): 605-609, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393114

RESUMO

AIM AND OBJECTIVE: The present study compared the frictional forces of three types of self-ligating lingual appliances. MATERIALS AND METHODS: The lingual appliances (2D, Forestadent; Alias, Ormco; and Clippy L, Tomy International) consisted of a self-ligating bracket (second premolar) and two self-ligating tubes (first and second molars) bonded to a stainless steel jig and attached to a "drawing-friction tester." Full-size and non-full-size stainless steel archwires were tested, and the static and kinetic friction acting on six lingual appliance/wire combinations was estimated (n = 5). Three-dimensional micro-computed tomography (micro-CT) analysis of each premolar bracket was performed. The frictional forces were compared between the bracket/wire combinations using the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The Alias and Clippy L bracket/wire combinations had greater contact between the wire surfaces and bracket slots compared to the 2D bracket/wire combination. For all lingual appliances, the static and kinetic frictional forces were significantly higher for the full-size than non-full-size archwire. The 2D bracket, which had a wider outer wing, had less frictional force than the other appliances. The Alias, which had a narrower outer wing, had a significantly lower frictional force than the Clippy L. CONCLUSIONS: Frictional force was significantly higher for heavier full-size bracket/archwire combinations than for non-full-size archwires. The 2D bracket had lower frictional force due to its archwire-holding mechanism. The outer wing width may influence the frictional resistance. CLINICAL SIGNIFICANCE: The frictional forces of self-ligating lingual appliances vary, and bracket design and archwire size may influence the frictional performance.


Assuntos
Braquetes Ortodônticos , Fios Ortodônticos , Ligas Dentárias , Análise do Estresse Dentário , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Aço Inoxidável , Titânio , Microtomografia por Raio-X
3.
Int J Oral Maxillofac Implants ; 36(4): 715-722, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34411210

RESUMO

PURPOSE: To evaluate the influence of age and trabecular microstructure on peri-implant strain in aging and young mice models under compressive load. MATERIALS AND METHODS: Eighteen 4-week-old female C57BL/6 mice (n = 6) were subjected to a 1.2% calcium content diet (young normal calcium group), and 7-month-old mice (n = 12) were randomly subjected to 0.01% and 1.2% calcium content diets (aging low and normal calcium groups, respectively) for 3 weeks. Histomorphometric and microcomputed tomography (micro-CT) analyses were used to investigate local alveolar bone microstructure. One maxilla segment from each group was reconstructed using micro-CT images to highlight the trabecular microstructure. A finite element analysis based on a computational model of the maxilla segment was performed to investigate peri-implant strain. Implants with three different diameters (0.3, 0.4, and 0.5 mm) were analyzed in these models. RESULTS: The aging low calcium group showed worse cancellous microstructure in hematoxylin and eosin (HE) staining, significantly increased osteoclast numbers (P < .05), and reduced bone volume fraction and trabecular thickness compared with the aging normal calcium group (P < .05). However, the young normal calcium group presented no difference in trabecular microstructure and osteoclast numbers compared with the aging normal calcium group. The aging low calcium group demonstrated increased strain intensity compared with the aging normal calcium group, whereas the young normal calcium and aging normal calcium groups showed comparable strain magnitude. The strain intensity of peri-implant bone increased with worse cancellous microstructure. When the diameter increased from 0.3 mm to 0.4 mm, the percentages of pathologic overload decreased regardless of bone microstructure. CONCLUSION: Deteriorated bone microstructure induced by a low calcium diet determined higher strain intensity, whereas, whenever age had no significant effect on trabecular microstructure, consequently, there was no substantial influence on strain. An increase of implant diameters can improve the strain distribution. Clinical decision-making should take into consideration the patient-specific and site-specific trabecular microstructure in preoperative assessment.


Assuntos
Implantes Dentários , Envelhecimento , Animais , Fenômenos Biomecânicos , Implantes Dentários/efeitos adversos , Feminino , Análise de Elementos Finitos , Humanos , Maxila , Camundongos , Camundongos Endogâmicos C57BL , Microtomografia por Raio-X
4.
Medicina (Kaunas) ; 57(8)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34440981

RESUMO

Background and Objectives: Ceramic veneers represent the most appropriate treatment option for minimally invasive aesthetic rehabilitation. For long-term clinical success, the accurate marginal and internal adaptation of dental restorations are of paramount importance. The aim of this in vitro study is to assess the effect of a novel (patented) design of veneers compared to conventional ones on their marginal and internal gap to the prepared tooth surface. Materials and Methods: Twenty-four lithium disilicate ceramic veneers are obtained using Computer-Aided-Design (CAD) and then milled using Computer-Aided-Manufacturing (CAM). The samples are divided into two groups: 12 conventional (CO) veneers (i.e., with a linear marginal contour) and 12 crenelated (CR) veneers, the latter with the novel sinusoidal marginal design. All samples are bonded to frontal teeth, and the adhesive interfaces are analyzed using two methods, optical microscopy and micro-Computed Tomography (CT): the former for the accuracy of the marginal gap and the latter for the internal gap (as well as for the homogeneity of the luting cement) of ceramic veneers. Results: STATA and one-way ANOVA tests reveal significant differences between CO and CR veneers: (i) the marginal gap is smaller for CR (64 µm) than for CO veneers (236 µm); (ii) the internal adaptation is better for CR veneers: for a cement width of up to 120 µm, the covered surface for the CR group is 81.5%, while for the CO group it is 64.5%; (iii) the mean of the porosities within the cement is not significantly different (3.4·106 µm3 for CO and 3.9·106 µm3 for CR veneers), with a higher standard deviation for the CO group. Analytical modeling is achieved for internal gaps using the micro-CT results. The characteristic functions obtained allow us to compare the volume of luting cement for the two types of veneers. Conclusion: The novel veneers design produces an improvement in the marginal and internal adaptation of the restorations to the prepared tooth surface. Thus, it provides favorable premises for better clinical performances.


Assuntos
Cerâmica , Microscopia , Desenho Assistido por Computador , Humanos , Teste de Materiais , Microtomografia por Raio-X
5.
Arch Oral Biol ; 130: 105216, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34365145

RESUMO

OBJECTIVES: The present study aimed to compare two different models of orthodontic tooth movement (OTM) in rats by evaluating tooth movement efficiency and periodontal tissues remodelling. DESIGN: Fifteen animals were randomly distributed into 3 groups: control group (untreated); ligature appliance (LA) as experimental OTM using a closed coil spring fixed around maxillary first molar by steel ligature; occlusal appliance (OA) as experimental OTM using a closed coil spring attached on the occlusal surface of the maxillary first molar. After 15 days, all animals were euthanized, and the maxilla of each animal was collected for qPCR, micro-computed tomography, and histological analyses. RESULTS: Interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha gene expressions were significantly upregulated in the animals of the LA group as compared to the other groups. No significant difference was observed in tooth displacement between both methods. The LA group presented higher linear bone loss and lower values of bone volume fraction, bone mineral density, trabecular number and increased values of trabecular separation compared to the other groups. The birefringent collagen content in the tension side of the periodontal ligament contained significantly lower collagen content in the LA group than in the control group. Furthermore, on the pressure side, the collagen content was significantly lower in the LA and OA groups than in the control group. CONCLUSIONS: The OA group presented little or no deleterious effect on periodontal tissues compared to the LA group, suggesting its use may be more reliable for OTM induction in rats for 15 days.


Assuntos
Osteoclastos , Técnicas de Movimentação Dentária , Animais , Modelos Teóricos , Ligamento Periodontal/diagnóstico por imagem , Periodonto , Ratos , Microtomografia por Raio-X
6.
Prog Orthod ; 22(1): 28, 2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34423388

RESUMO

OBJECTIVE: The aim was to investigate the effect of mechanical vibration on root resorption with or without orthodontic force application. MATERIAL AND METHODS: Twenty patients who required maxillary premolar extractions as part of orthodontic treatment were randomly divided into two groups of 10: no-force group and force group. Using a split-mouth procedure, each patient's maxillary first premolar teeth were randomly assigned as either vibration or control side for both groups. A buccally directed vibration of 50 Hz, with an Oral-B HummingBird device, was applied to the maxillary first premolar for 10 min/day for 12 weeks. After the force application period, the maxillary first premolars were extracted and scanned with micro-computed tomography. Fiji (ImageJ), performing slice-by-slice quantitative volumetric measurements, was used for resorption crater calculation. Total crater volumes were compared with the Wilcoxon and Mann-Whitney U tests. RESULTS: The total crater volumes in the force and no-force groups were 0.476 mm3 and 0.017 mm3 on the vibration side and 0.462 mm3 and 0.031 mm3 on the control side, respectively. There was no statistical difference between the vibration and control sides (P > 0.05). There was more resorption by volume in the force group when compared to the no-force group (P < 0.05). CONCLUSION: Mechanical vibration did not have a beneficial effect on reducing root resorption; however, force application caused significant root resorption.


Assuntos
Reabsorção da Raiz , Humanos , Reabsorção da Raiz/diagnóstico por imagem , Reabsorção da Raiz/etiologia , Técnicas de Movimentação Dentária , Raiz Dentária , Vibração , Microtomografia por Raio-X
7.
Beijing Da Xue Xue Bao Yi Xue Ban ; 53(4): 758-763, 2021 Aug 18.
Artigo em Chinês | MEDLINE | ID: mdl-34393241

RESUMO

OBJECTIVE: To develop dexamethasone plus minocycline-loaded liposomes (Dex/Mino liposomes) and apply them to improve bioinert polyetheretherketone (PEEK) surface, which could prevent post-operative bacterial contamination, enhance ossification for physiologic osseointegration, and finally reduce implant failure rates. METHODS: Dex/Mino liposomes were covalently grafted onto the PEEK surface using polydopamine (pDA) coating as a medium. Confocal laser scanning microscopy was used to confirm the binding of fluorescently labeled liposomes onto the PEEK substrate, and a microplate reader was used to semiquantitatively measure the average fluorescence intensity of fluorescently labeled liposome-decorated PEEK surfaces. Moreover, the mouse subcutaneous infection model and the beagle femur implantation model were respectively conducted to verify the bioactivity of Dex/Mino liposome-modified PEEK in vivo, by means of micro computed tomography (micro-CT) and hematoxylin and eosin (HE) staining analysis. RESULTS: The qualitative and quantitative results of fluorescently labeled liposomes showed that, the red fluorescence intensity of the PEEK-pDA-lipo group was stronger than that of the PEEK-NF-lipo group (P < 0.05); the liposomes were successfully and uniformly decorated on the PEEK surfaces due to the pDA coating. After mouse subcutaneous implantation of PEEKs for 24 hours, HE staining results showed that the number of inflammatory cells in the PEEK-Dex/Mino lipo group were lower than that in the inert PEEK group (P < 0.05), indicating a lower degree of infection in the test group. These results suggested that the Mino released from the liposome-functionalized surface provided an effective bacteriostasis in vivo. After beagle femoral implantation of PEEK for 8 weeks, micro-CT results showed that the PEEK-Dex/Mino lipo group newly formed more continuous bone when compared with the inert PEEK group; HE staining results showed that more new bones were formed in the PEEK-Dex/Mino lipo group than in the inert PEEK group, which were firmly bonded to the functionalized PEEK surface and extended along the PEEK interface. These results suggested that the Dex released from the liposome-functionalized surface induced effective bone regeneration in vivo. CONCLUSION: Dex/Mino liposome modification enhanced the bioactivity of inert PEEK, the functionalized PEEK with enhanced antibacterial and osseointegrative capacity has great potential as an orthopedic/dental implant material for clinical application.


Assuntos
Lipossomos , Osseointegração , Animais , Benzofenonas , Cães , Cetonas , Camundongos , Polietilenoglicóis , Polímeros , Propriedades de Superfície , Microtomografia por Raio-X
8.
Beijing Da Xue Xue Bao Yi Xue Ban ; 53(4): 764-769, 2021 Aug 18.
Artigo em Chinês | MEDLINE | ID: mdl-34393242

RESUMO

OBJECTIVE: To evaluate the influence of base materials on stress distribution in endodontically treated maxillary premolars restored with endocrowns using three-dimensional finite element analysis. METHODS: A maxillary second premolar was scanned by Micro-CT and a three-dimensional finite element model of ceramic endocrown with 1 mm thickness of base was established. A model without base was also established as a negative control. Four kinds of conventional base materials with different elastic modulus were adopted: light cure glass ionomer(3M Vitrebond, 3 657 MPa), flowable composite resin(3M Filtek Z350XT Flowable Restorative, 7 300 MPa), high strength glass ionomer(GC Fuji Ⅸ, 13 130 MPa), and posterior composite resin(3M Filtek P60, 19 700 MPa). With a 200 N force loaded vertically and obliquely, the distribution and magnitude of stress in the tooth tissue and adhesive layer were investigated by three-dimensional finite element analysis. RESULTS: The maximum von Mises stress values(vertical/oblique) in dentin and adhesive layer were measured as follows: (1) no base material: 19.39/70.49 MPa in dentin and 6.97/17.97 MPa in adhesive layer; (2) light cure glass ionomer: 19.00/69.75 MPa in dentin and 6.87/16.30 MPa in adhesive layer; (3) flowable composite resin: 18.78/69.33 MPa in dentin and 6.79/16.17 MPa in adhesive layer; (4) high strength glass ionomer: 18.71/69.20 MPa in dentin and 6.74/16.07 MPa in adhesive layer; (5) posterior composite resin: 18.61/69.03 MPa in dentin and 6.70/16.01 MPa in adhesive layer. Under the same loading condition, models with different elastic moduli of base materials had similar stress distribution patterns. The von Mises stress of tooth tissue was mainly concentrated in the tooth cervix. Under oblique load, the regions where von Mises stress concentrated in were similar to those under a vertical load, but the values increased. The stress concentration in the tooth cervix was alleviated in models with base materials compared with the model without base material. The maximum von Mises stress in the tooth tissue and adhesive layer decreased when the elastic modulus of base materials increased and got close to that of dentin. CONCLUSION: The posterior composite resin of which the elastic moduli is high and close to that of dentin is recommended as base material for premolar endocrowns to alleviate the concentration of stress in tooth cervix and adhesive layer.


Assuntos
Resinas Compostas , Colo do Dente , Dente Pré-Molar , Cerâmica , Análise do Estresse Dentário , Dentina , Análise de Elementos Finitos , Humanos , Teste de Materiais , Estresse Mecânico , Microtomografia por Raio-X
9.
Gen Dent ; 69(5): 39-42, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34424210

RESUMO

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.


Assuntos
Cavidade Pulpar , Maxila , Cavidade Pulpar/diagnóstico por imagem , Humanos , Radiografia Dentária Digital , Reprodutibilidade dos Testes , Microtomografia por Raio-X
10.
Nat Commun ; 12(1): 4974, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404802

RESUMO

Osteoporosis affects millions worldwide and is often caused by osteoclast induced bone loss. Here, we identify the cytoplasmic protein ELMO1 as an important 'signaling node' in osteoclasts. We note that ELMO1 SNPs associate with bone abnormalities in humans, and that ELMO1 deletion in mice reduces bone loss in four in vivo models: osteoprotegerin deficiency, ovariectomy, and two types of inflammatory arthritis. Our transcriptomic analyses coupled with CRISPR/Cas9 genetic deletion identify Elmo1 associated regulators of osteoclast function, including cathepsin G and myeloperoxidase. Further, we define the 'ELMO1 interactome' in osteoclasts via proteomics and reveal proteins required for bone degradation. ELMO1 also contributes to osteoclast sealing zone on bone-like surfaces and distribution of osteoclast-specific proteases. Finally, a 3D structure-based ELMO1 inhibitory peptide reduces bone resorption in wild type osteoclasts. Collectively, we identify ELMO1 as a signaling hub that regulates osteoclast function and bone loss, with relevance to osteoporosis and arthritis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doenças Ósseas Metabólicas/metabolismo , Osteoclastos/metabolismo , Osteoporose/metabolismo , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Animais , Artrite/patologia , Reabsorção Óssea/metabolismo , Sistemas CRISPR-Cas , Feminino , Camundongos , Camundongos Knockout , Osteoprotegerina/deficiência , Ovariectomia , Transcriptoma , Microtomografia por Raio-X
11.
Analyst ; 146(14): 4683-4699, 2021 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-34195707

RESUMO

In this proof-of-principle study, we established and implemented a cross-modality imaging (CMI) pipeline to characterize and compare bisphosphonate (BIS)-treated jawbones of Sprague-Dawley rats after tooth extraction after physical therapies (photobiomodulation and extracorporeal shockwave therapy (PBMT and ESWT)). We showcase the feasibility of such a CMI approach and its compatibility across imaging modalities to probe the same region of interest (ROI) of the same jawbone. Jawbones were imaged in toto in 3D using micro-Computed Tomography to identify ROIs for subsequent sequential 2D analysis using well-established technologies such as Atomic Force Microscopy and Scanning Electron Microscopy, and recent imaging approaches in biomedical settings, such as micro-X-Ray Fluorescence Spectroscopy. By combining these four modalities, multiscale information on the morphology, topography, mechanical stiffness (Young's modulus), and calcium, zinc and phosphorus concentrations of the bone was collected. Based on the CMI pipeline, we characterized and compared the jawbones of a previously published clinically relevant rat model of BIS-related osteonecrosis of the jawbone (BRONJ) before and after treatment with BISs, PBMT and ESWT. While we did not find that physical therapies altered the mechanical and elemental jawbone parameters with significance (probably due to the small sample size of only up to 5 samples per group), both ESWT and PBMT reduced pore thicknesses and bone-to-enamel distances significantly compared to the controls. Although focused on BIS-treated jawbones, the established CMI platform can be beneficial in the study of bone-related diseases in general (such as osteoarthritis or -porosis) to acquire complementary hallmarks and better characterize disease status and alleviation potentials.


Assuntos
Tratamento por Ondas de Choque Extracorpóreas , Osteoartrite , Animais , Difosfonatos/toxicidade , Camundongos , Ratos , Ratos Sprague-Dawley , Microtomografia por Raio-X
12.
Indian J Dent Res ; 32(1): 79-86, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34269242

RESUMO

Objective: To compare and evaluate the retreatability of calcium silicate-based root canal sealers and epoxy resin-based root canal sealers in curved canals using micro-CT scanning. Materials and Methods: Forty-five maxillary molars with curved roots were selected after confirming with the Schneiders test. Teeth were decoronated near the cemento-enamel junction and moderate to severely curved canals were selected for the study using cone-beam computed tomography. All the samples were subjected to pre-operative micro-CT scanning. Cleaning and shaping were done using step-back preparation, obturation was done using lateral compaction technique, and homogeneous obturation was achieved. All the specimens were kept in 10 mL of phosphate buffered-saline solution at a pH of 8.4 for 48 h and transferred to a plastic container containing moistened foam with 10 mL of phosphate- buffered saline solution, and stored at 37 °C with 100% relative humidity for 4 months. Retreatment was performed for all the samples using Protaper universal retreatment files. Micro-CT scanning was performed to compare and evaluate the remaining sealer volume and resultant cracks formed in the root canal after retreatment. Results: The volume of sealer remaining in the root canal and the length of a crack within the groups were analysed using kruskal-Wallis test and among the groups using post-hoc scheffe test showed that more sealer present in the Diaproseal sealer followed by MTA Fillapex and Bioroot RCS and more crack length was seen in Diaproseal sealer followed by MTA Fillapex and no visible cracks were seen in Bioroot RCS, which had statistically significant results with a P value of < 0.05. Conclusion: Within the limitations of the study it was concluded that in-terms of retrievability, Diaproseal sealer was the best among the tested groups followed by MTA Fillapex and Bioroot RCS.


Assuntos
Resinas Epóxi , Materiais Restauradores do Canal Radicular , Compostos de Cálcio , Cavidade Pulpar/diagnóstico por imagem , Silicatos , Microtomografia por Raio-X
13.
Biomaterials ; 275: 120936, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34303178

RESUMO

Macrophage-targeted therapies, including macrophage colony-stimulating factor 1 (CSF1), have been shown to have pro-repair impacts post-fracture. Preclinical/clinical applications of CSF1 have been expedited by development of chimeric CSF1-Fc which has extended circulating half-life. Here, we used mouse models to investigate the bone regenerative potential of CSF1-Fc in healthy and osteoporotic fracture. We also explored whether combination of CSF1-Fc with interleukin (IL)-4 provided additional fracture healing benefit in osteopenic bone. Micro-computed tomography, in situ histomorphometry, and bone mechanical parameters were used to assess systemic impacts of CSF1-Fc therapy in naive mice (male and female young, adult and geriatric). An intermittent CSF1-Fc regimen was optimized to mitigate undesirable impacts on bone resorption and hepatosplenomegaly, irrespective of age or gender. The intermittent CSF1-Fc regimen was tested in a mid-diaphyseal femoral fracture model in healthy bones with treatment initiated 1-day post-fracture. Weekly CSF1-Fc did not impact osteoclasts but increased osteal macrophages and improved fracture strength. Importantly, this treatment regimen also improved fracture union and strength in an ovariectomy-model of delayed fracture repair. Combining CSF1-Fc with IL-4 initiated 1-week post-fracture reduced the efficacy of CSF1-Fc. This study describes a novel strategy to specifically achieve bone regenerative actions of CSF1-Fc that has the potential to alleviate fragility fracture morbidity and mortality.


Assuntos
Consolidação da Fratura , Fator Estimulador de Colônias de Macrófagos , Animais , Osso e Ossos , Feminino , Macrófagos , Masculino , Camundongos , Microtomografia por Raio-X
14.
J Biomech ; 125: 110590, 2021 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-34214861

RESUMO

The cerebral circulation is a common site of vascular lesions and concurrent hemodynamic accidents, which often lead to serious neurological disabilities. Recent advances in understanding pathogenesis, improving diagnostics and developing new treatment methods for these conditions result from an interdisciplinary approach to the problem - linking clinical sciences, basic medical sciences and hemodynamical analyses. Most common techniques used in such studies include computational fluid dynamics, which allows for development of 3D models of cerebral vasculature, basing on radiological studies. However, these methods remain flawed, mainly because of their spatial resolution, which is not high enough to visualize the smallest arterial branches (perforating branches) in the models. That leaves the perforators (<1.0 mm) out of most of the contemporary studies, whilst their clinical importance is widely recognized in clinical practice. Obstruction of these vessels by atherosclerotic plaques, thrombi or implantation of flow diverting stents may result in neurological complications such as paralysis or coma. Our research team has recently developed a new method of creating 3D models of the cerebral arterial system based on anatomical specimens and micro computed tomography (micro-CT). We have infused fresh brainstem vasculature specimens with contrast medium, subsequently scanned them using an industrial-grade micro-CT system and finally, created spatial models, which included branches of diameter less than 0.1 mm. None of the current methods have been able to produce models of detail as high as this, which allows us to presume, that our procedure may open up new opportunities for hemodynamical studies within cerebral circulation and beyond.


Assuntos
Artérias Cerebrais , Hemodinâmica , Artérias Cerebrais/diagnóstico por imagem , Circulação Cerebrovascular , Stents , Microtomografia por Raio-X
15.
Forensic Sci Int ; 325: 110789, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34217913

RESUMO

Cases of child abuse and homicide are amongst the biggest challenges investigators face, with complex evidence bases often strongly contested and reliant on specialist interpretation of the medical evidence. In many cases, this medical evidence includes examination of the deceased's skeleton using different macroscopic and microscopic imaging methods. Rib fractures are a common concern when examining suspicious cases and much research has been conducted on their causes. The role of CPR in particular has been controversial and therefore a clear assessment of the fracture distribution is crucial. Recent studies have shown the benefit of imaging techniques such as Computed Tomography, although the gold standard remains histology. This paper presents three cases of suspected non-accidental rib fractures of infants which had been examined using micro-CT and histology. Micro-CT has been shown to be superior to medical CT as it achieves a greater resolution, making it effective for paediatric post-mortem imaging. Micro-CT observations were compared retrospectively to the histology, which demonstrated that micro-CT found 69% of the fractures identified histologically as well as an additional 22% not identified through histology. As well as complimenting histological analysis, the extent to which micro-CT can enhance the overall examination of paediatric non-accidental injuries is also discussed.


Assuntos
Fraturas das Costelas/diagnóstico por imagem , Microtomografia por Raio-X , Maus-Tratos Infantis/diagnóstico , Pré-Escolar , Medicina Legal , Consolidação da Fratura , Humanos , Imageamento Tridimensional , Lactente , Fraturas das Costelas/patologia
16.
Int J Mol Sci ; 22(14)2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34299241

RESUMO

In this paper, we suggest that the atmospheric pressure plasma treatment of pure titanium metal may be useful for improving the ability of rat bone marrow cells (RBMCs) to induce hard tissue differentiation. Previous studies have reported that the use of argon gas induces a higher degree of hard tissue formation. Therefore, this study compares the effects of plasma treatment with argon gas on the initial adhesion ability and hard tissue differentiation-inducing ability of RBMCs. A commercially available titanium metal plate was used as the experimental material. A plate polished using water-resistant abrasive paper #1500 was used as the control, and a plate irradiated with argon mixed with atmospheric pressure plasma was used as the experimental plate. No structural change was observed on the surface of the titanium metal plate in the scanning electron microscopy results, and no change in the surface roughness was observed via scanning probe microscopy. X-ray photoelectron spectroscopy showed a decrease in the carbon peak and the formation of hydroxide in the experimental group. In the distilled water drop test, a significant decrease in the contact angle was observed for the experimental group, and the results indicated superhydrophilicity. Furthermore, the bovine serum albumin adsorption, initial adhesion of RBMCs, alkaline phosphatase activity, calcium deposition, and genetic marker expression of rat bone marrow cells were higher in the experimental group than those in the control group at all time points. Rat distal femur model are used as in vivo model. Additionally, microcomputed tomography analysis showed significantly higher results for the experimental group, indicating a large amount of the formed hard tissue. Histopathological evaluation also confirmed the presence of a prominent newly formed bone seen in the images of the experimental group. These results indicate that the atmospheric pressure plasma treatment with argon gas imparts superhydrophilicity, without changing the properties of the pure titanium plate surface. It was also clarified that it affects the initial adhesion of bone marrow cells and the induction of hard tissue differentiation.


Assuntos
Argônio/farmacologia , Osseointegração/efeitos dos fármacos , Gases em Plasma/química , Animais , Argônio/química , Pressão Atmosférica , Células da Medula Óssea/efeitos dos fármacos , Adesão Celular/efeitos dos fármacos , Masculino , Microscopia Eletrônica de Varredura/métodos , Osseointegração/fisiologia , Osteogênese/efeitos dos fármacos , Espectroscopia Fotoeletrônica/métodos , Gases em Plasma/farmacologia , Ratos , Ratos Sprague-Dawley , Propriedades de Superfície , Titânio/química , Microtomografia por Raio-X/métodos
17.
Commun Biol ; 4(1): 863, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267313

RESUMO

Organisms comprise multiple interacting parts, but few quantitative studies have analysed multi-element systems, limiting understanding of phenotypic evolution. We investigate how disparity of vertebral morphology varies along the axial column of mammalian carnivores - a chain of 27 subunits - and the extent to which morphological variation have been structured by evolutionary constraints and locomotory adaptation. We find that lumbars and posterior thoracics exhibit high individual disparity but low serial differentiation. They are pervasively recruited into locomotory functions and exhibit relaxed evolutionary constraint. More anterior vertebrae also show signals of locomotory adaptation, but nevertheless have low individual disparity and constrained patterns of evolution, characterised by low-dimensional shape changes. Our findings demonstrate the importance of the thoracolumbar region as an innovation enabling evolutionary versatility of mammalian locomotion. Moreover, they underscore the complexity of phenotypic macroevolution of multi-element systems and that the strength of ecomorphological signal does not have a predictable influence on macroevolutionary outcomes.


Assuntos
Adaptação Fisiológica/fisiologia , Evolução Biológica , Carnivoridade/fisiologia , Locomoção/fisiologia , Mamíferos/fisiologia , Coluna Vertebral/fisiologia , Análise de Variância , Animais , Atividade Motora/fisiologia , Coluna Vertebral/anatomia & histologia , Coluna Vertebral/diagnóstico por imagem , Fatores de Tempo , Tomografia Computadorizada por Raios X , Microtomografia por Raio-X
18.
Int J Mol Sci ; 22(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34298988

RESUMO

This study evaluated the biocompatibility and biological performance of novel additive-manufactured bioabsorbable iron-based porous suture anchors (iron_SAs). Two types of bioabsorbable iron_SAs, with double- and triple-helical structures (iron_SA_2_helix and iron_SA_3_helix, respectively), were compared with the synthetic polymer-based bioabsorbable suture anchor (polymer_SAs). An in vitro mechanical test, MTT assay, and scanning electron microscope (SEM) analysis were performed. An in vivo animal study was also performed. The three types of suture anchors were randomly implanted in the outer cortex of the lateral femoral condyle. The ultimate in vitro pullout strength of the iron_SA_3_helix group was significantly higher than the iron_SA_2_helix and polymer_SA groups. The MTT assay findings demonstrated no significant cytotoxicity, and the SEM analysis showed cells attachment on implant surface. The ultimate failure load of the iron_SA_3_helix group was significantly higher than that of the polymer_SA group. The micro-CT analysis indicated the iron_SA_3_helix group showed a higher bone volume fraction (BV/TV) after surgery. Moreover, both iron SAs underwent degradation with time. Iron_SAs with triple-helical threads and a porous structure demonstrated better mechanical strength and high biocompatibility after short-term implantation. The combined advantages of the mechanical superiority of the iron metal and the possibility of absorption after implantation make the iron_SA a suitable candidate for further development.


Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis , Âncoras de Sutura , Alanina Transaminase/sangue , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/toxicidade , Fenômenos Biomecânicos , Nitrogênio da Ureia Sanguínea , Fosfatos de Cálcio/química , Fosfatos de Cálcio/toxicidade , Sulfato de Cálcio/administração & dosagem , Sulfato de Cálcio/química , Sulfato de Cálcio/toxicidade , Creatinina/sangue , Desenho de Equipamento , Fêmur/diagnóstico por imagem , Fêmur/ultraestrutura , Ferro , Lasers , Teste de Materiais , Microscopia Eletrônica de Varredura , Estrutura Molecular , Osseointegração , Polímeros/química , Polímeros/toxicidade , Porosidade , Coelhos , Distribuição Aleatória , Resistência à Tração , Vísceras , Microtomografia por Raio-X
19.
Int Endod J ; 54(10): 1819-1839, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34196006

RESUMO

AIM: The International Endodontic Journal (IEJ) has served as a platform for research and clinical practice in Endodontics since 1967. This study provides a bibliographic analysis and overview of the publications that have appeared in the IEJ from 1967 to 2020. METHODOLOGY: A literature search was performed in Elsevier's Scopus database to locate all the publications of the International Endodontic Journal. Various bibliometric software packages including the open-source visualization software Gephi and Biblioshiny (version 2.0) were employed for data visualization and analysis. RESULTS: A total of 3739 records with citation and bibliographic details were selected and retrieved to allow a bibliometric analysis to be performed. The bibliometric analysis indicates that the IEJ has grown both in terms of productivity and influence. Over time, the journal has been associated with an increase in the number of manuscripts published and the citations they have attracted, but with minor downward fluctuations in citations in the last few years. Bibliographic coupling of the IEJ articles revealed that the major research themes published in the journal include 'endodontics', 'root canal treatment', 'calcium hydroxide', 'apical periodontitis', 'mineral trioxide aggregate', 'microbiology', 'cyclic fatigue', 'cone-beam computed tomography' and 'micro-computed tomography'. Authors affiliated to institutions in the UK were the major contributors to the journal and were linked with other countries such as Brazil, USA and Malaysia. The largest number of publications were from the University of São Paulo, Brazil. CONCLUSION: The IEJ is one of the leading journals in Endodontology and has been providing a platform for innovative research and clinical reports for more than 50 years. Publications have been associated with a wide range of authors, institutions and countries around the world.


Assuntos
Bibliometria , Endodontia , Tomografia Computadorizada de Feixe Cônico , Bases de Dados Factuais , Microtomografia por Raio-X
20.
Phys Med ; 88: 175-192, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34284331

RESUMO

PURPOSE: Micron-scale computed tomography (micro-CT) imaging is a ubiquitous, cost-effective, and non-invasive three-dimensional imaging modality. We review recent developments and applications of micro-CT for preclinical research. METHODS: Based on a comprehensive review of recent micro-CT literature, we summarize features of state-of-the-art hardware and ongoing challenges and promising research directions in the field. RESULTS: Representative features of commercially available micro-CT scanners and some new applications for both in vivo and ex vivo imaging are described. New advancements include spectral scanning using dual-energy micro-CT based on energy-integrating detectors or a new generation of photon-counting x-ray detectors (PCDs). Beyond two-material discrimination, PCDs enable quantitative differentiation of intrinsic tissues from one or more extrinsic contrast agents. When these extrinsic contrast agents are incorporated into a nanoparticle platform (e.g. liposomes), novel micro-CT imaging applications are possible such as combined therapy and diagnostic imaging in the field of cancer theranostics. Another major area of research in micro-CT is in x-ray phase contrast (XPC) imaging. XPC imaging opens CT to many new imaging applications because phase changes are more sensitive to density variations in soft tissues than standard absorption imaging. We further review the impact of deep learning on micro-CT. We feature several recent works which have successfully applied deep learning to micro-CT data, and we outline several challenges specific to micro-CT. CONCLUSIONS: All of these advancements establish micro-CT imaging at the forefront of preclinical research, able to provide anatomical, functional, and even molecular information while serving as a testbench for translational research.


Assuntos
Meios de Contraste , Fótons , Animais , Imagens de Fantasmas , Tomógrafos Computadorizados , Microtomografia por Raio-X
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