Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 374
Filtrar
1.
Dental Press J Orthod ; 26(1): e211965, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33729291

RESUMO

OBJECTIVE: The aim of this study was to evaluate the thickness of the zygomatic-maxillary cortical bone using computed tomography in different skeletal patterns. METHODS: A total of 54 patients of both sexes, divided into three groups according to the vertical skeletal pattern, were evaluated for cortical bone thickness of the anterior slope of the zygomatic process of the maxilla, using cone beam computed tomography. Measurements were made at 2mm, 4mm, 6mm, 8mm and 10mm above from first molar mesial root apex. Vertical skeletal pattern was determined by Frankfurt mandibular angle (FMA). RESULTS: The hyperdivergent pattern had the lowest cortical thickness value, nevertheless, no patient in the hyperdivergent group presented cortical thickness exceeding 2mm, and no patient in the hypodivergent group presented cortical thickness less than 1mm. However, the correlation between cortical thickness and mandibular plane angle was weak and not significant. CONCLUSION: Although higher prevalence of thick cortical was observed in the hypodivergent patients, and thin cortical groups in the hyperdivergent group, the vertical skeletal pattern could not be used as determinant of the zygomatic-maxillary cortical thickness.


Assuntos
Mandíbula , Maxila , Cefalometria , Tomografia Computadorizada de Feixe Cônico , Osso Cortical/diagnóstico por imagem , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem
2.
Medicine (Baltimore) ; 100(2): e24099, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33466177

RESUMO

BACKGROUND: To explore the ideal trajectory of lumbar cortical bone trajectory screws and provide the optimal placement scheme in clinical applications. METHODS: Lumbar computed tomography (CT) data of 40 patients in our hospital were selected, and the cortical vertebral bone contour model was reconstructed in three dimensions (3D). Depending on the different regions of the screw through the entrance and exit of the pedicle, 9 trajectories were obtained through combinational design: T-Aa, T-Ab, T-Ac, T-Ba, T-Bb, T-Bc, T-Ca, T-Cb, and T-Cc. Cortical bone trajectory (CBT) screws with appropriate diameters were selected to simulate screw placement and measure the parameters corresponding to each trajectory (screw path diameter, screw trajectory length, cephalad angle, and lateral angle), and then determine the optimal screw according to the screw parameters and screw safety. Then, 23 patients in our hospital were selected, and the navigation template was designed based on the ideal trajectory before operation, CBT screws were placed during the operation to further verify the safety and feasibility of the ideal trajectory. RESULTS: T-Bc and T-Bb are the ideal screw trajectories for L1-L2 and L3-L5, respectively. The screw placement point is located at the intersection of the inner 1/3 vertical line of the superior facet joint and the bottom 1/3 horizontal line of the outer crest of the vertebral lamina (i.e., 2-4 mm inward at the bottom 1/3 of the outer crest of the vertebral lamina). CBT screws were successfully placed based on the ideal screw trajectory in clinical practice. During the operation or the follow-up period, there were no adverse events. CONCLUSION: CBT screw placement based on the ideal screw trajectory is a safe and reliable method for achieving effective fixation and satisfactory postoperative effects.


Assuntos
Osso Cortical/lesões , Fixação de Fratura/instrumentação , Vértebras Lombares/lesões , Parafusos Pediculares , Fraturas da Coluna Vertebral/cirurgia , Simulação por Computador , Osso Cortical/diagnóstico por imagem , Osso Cortical/cirurgia , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Modelos Anatômicos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Articulação Zigapofisária/diagnóstico por imagem , Articulação Zigapofisária/cirurgia
3.
Angle Orthod ; 90(6): 794-800, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378521

RESUMO

OBJECTIVES: To determine whether there was a correlation between patients' bone thickness and time spent in orthodontic treatment. The secondary aim was to study the influence of Angle classification, extraction treatment, and age on overall treatment duration. MATERIALS AND METHODS: In this retrospective study, records of 971 orthodontic patients from two centers were reviewed and 500 subjects were included after imposing inclusion/exclusion criteria. The Mental Index was used to determine patients' bone density. For the Mental Index, a line perpendicular to the inferior border of the mandible was drawn on a panoramic radiograph so that it intersected the inferior border of the mental foramen. The mandibular cortical thickness was measured along this line. Two-sample t-test or a chi-square test, followed by multiple linear regression, were used to identify the factors affecting treatment duration. RESULTS: Mandibular cortical thickness was negatively associated with treatment time for all subjects (P < .05). After adjusting for covariables, it remained significant for center-1, but non-significant for center-2 subjects. Angle Class II and Class III malocclusion, extraction therapy, and age had significant positive correlations with treatment duration (P < .05). CONCLUSIONS: There is a negative correlation between the mandibular cortical thickness and orthodontic treatment duration. An extraction treatment plan and treatment of Angle Class II and Class III malocclusions significantly increase the duration of orthodontic treatment. Additionally, patients over 12 years of age have shorter treatment times compared to patients under 12 years of age.


Assuntos
Má Oclusão de Angle Classe II , Mandíbula , Cefalometria , Criança , Osso Cortical/diagnóstico por imagem , Humanos , Má Oclusão de Angle Classe II/diagnóstico por imagem , Má Oclusão de Angle Classe II/terapia , Mandíbula/diagnóstico por imagem , Radiografia Panorâmica , Estudos Retrospectivos
4.
Medicine (Baltimore) ; 99(40): e22186, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33019393

RESUMO

This study aimed to verify the relationship between the number of fusion level and the risk of screw loosening by using cortical bone trajectory (CBT) screws in patients with lumbar degenerative disease.We retrospectively reviewed the serial plain radiograph images of lumbar degenerative disease patients who had undergone posterior fixation and fusion surgery with CBT from 2014. All included patients should have been followed-up with computed tomography scan or plain radiograph for at least 6 months after operation. We individually evaluated the prevalence of screw loosening according to each vertebral level. We also determined whether the number of screw fixation affected the prevalence of screw loosening and whether S1 fixation increased the risk of screw loosening.The screw-loosening rates were high at the S1 level. Moreover, although fixation involved to S1, the loosening rates evidently increased (Fisher exact test, P = .002). The screw-loosening rate was 6.56% in 2 level fusion. However, it increased with the number of fusion levels (3 level: 25.00%, 4 level: 51.16%, and 5 level: 62.50%). To investigate if the number of fusion level affected the S1 screw loosening, we classified the cohort of patients into either involving S1 (S1+ group) or not (S1- group) according to different fusion levels (). The screw loosening between 2 group in 2 (5.56% vs 6.98%) and 3 fusion level (26.32% vs 22.73%) did not exhibit any significant difference. Interestingly, significantly high screw loosening was found in 4 fusion level (60.00% vs 15.38%), indicating that the higher fusion level (4 level) can directly increase the risk of S1 screw loosening.Our data confirmed that the screw-loosening rate increases rate when long segment CBT fixation involves to S1. Therefore, in case of long-segment fixation by using CBT screw, surgeons should be aware of the fusion level of S1.


Assuntos
Parafusos Ósseos , Degeneração do Disco Intervertebral/cirurgia , Deslocamento do Disco Intervertebral/cirurgia , Fusão Vertebral/instrumentação , Osso Cortical/diagnóstico por imagem , Análise de Falha de Equipamento/métodos , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
5.
Am J Orthod Dentofacial Orthop ; 158(6): 783-798.e20, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33077369

RESUMO

INTRODUCTION: Safe zone maps are useful for the clinician to plan miniscrew insertion and possibly reduce radiation exposure. This study aimed to investigate the available evidence regarding the presence of sufficient interradicular space and adequate cortical bone thickness in patients with a complete permanent dentition, in the vestibular and palatal or lingual interradicular sites, mesial to the second molar. METHODS: PubMed, Scopus, Web of Science, Cochrane Library, and OpenGrey databases were searched up to January 2019 for observational studies involving patients with fully erupted second molars that investigated the amount of interradicular space and/or the cortical thickness of the alveolar processes using 3-dimensional data sets. A custom tool was prepared and used to assess the risk of bias in individual studies. A meta-analysis was performed when at least 4 different studies evaluated 1 identical parameter homogeneously. Publication bias was assessed with the Egger linear regression test. RESULTS: Twenty-seven observational articles were included in the qualitative synthesis. Only 11 articles were at low risk of bias. Fifteen articles were included in the meta-analysis. The results were graphically reported in "safe-zone" maps. CONCLUSIONS: In the maxilla, the most suitable insertion sites are those from mesial to the first molar to distal to the first premolar, and between the canine and the lateral incisor, all at 6 mm from the cementoenamel junction. In those areas, the cortical bone has adequate thickness, not requiring predrilling. In the mandible, the preferable vestibular interradicular spaces are those between first and second molars and between first and second premolars, both at 5 mm from the cementoenamel junction, and predrilling is suggested in these areas. TRIAL REGISTRATION NUMBER: PROSPERO CRD42016042081.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Raiz Dentária , Osso Cortical/diagnóstico por imagem , Humanos , Mandíbula/diagnóstico por imagem , Maxila/diagnóstico por imagem , Raiz Dentária/diagnóstico por imagem
6.
Int J Oral Maxillofac Implants ; 35(5): 879-887, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991637

RESUMO

PURPOSE: To evaluate the influence on healing of the bony window elevated inward in the sinus cavity as a cortical bone graft. MATERIALS AND METHODS: Eighteen rabbits were included in the experiment. At the test sites (bony window), the antrostomy was prepared and the remaining bony window was elevated together with the sinus mucosa. At the control sites, the bony window was gently detached before the sinus mucosa elevation and discarded. The space obtained was grafted with deproteinized bovine bone mineral (DBBM). A collagen membrane was positioned on the antrostomy at both sides. The rabbits were euthanized after 2, 4, and 8 weeks in groups of six each. Histologic analyses in different regions of the elevated space were carried out, and a Wilcoxon test was used to estimate differences. Microcomputed tomography (microCT) analyses were also performed. RESULTS: After 2 weeks of healing, higher proportions of new bone were found in the test group compared with the control group due to the higher amount of bone formed in the region subjacent to the sinus mucosa. In this region, higher amounts of new bone were also found in the test group after 4 (P = .028) and 8 weeks of healing (P = .345). After 8 weeks of healing, the percentage of new bone was higher at the control sites compared with the test sites, with the proportions being 25.4% ± 3.2% and 21.3% ± 6.1%, respectively. In this period of evaluation, the bony window contributed with 20.1% ± 5.3% of vital bone in the test group. A fraction of 60.4% ± 10.8% of its surface was surrounded by new bone. In the microCT analysis, after 8 weeks of healing, fractions of 22.3% ± 1.6% and 22.2% ± 0.7% of bone were found in the test and control groups, respectively. CONCLUSION: The presence of the bony window positively influenced the healing in the elevated space, especially in the submucosa region. The bony window was vital and incorporated into newly formed bone.


Assuntos
Levantamento do Assoalho do Seio Maxilar , Animais , Transplante Ósseo , Bovinos , Osso Cortical/diagnóstico por imagem , Osso Cortical/cirurgia , Coelhos , Cicatrização , Microtomografia por Raio-X
7.
J Bone Miner Metab ; 38(6): 826-838, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32519249

RESUMO

INTRODUCTION: Second-generation high-resolution peripheral quantitative computed tomography (HR-pQCT) has provide higher quality of bone images with a voxel size of 61 µm, enabling direct measurements of trabecular thickness. In addition to the standard parameters, the non-metric trabecular parameters such as trabecular morphology (plate to rod-like structures), connectivity, and anisotropy can also be analyzed. The purpose of this study is to investigate deterioration of bone microstructure in healthy Japanese women by measuring standard and non-metric parameters using HR-pQCT. MATERIALS AND METHODS: Study participants were 61 healthy Japanese women (31-70 years). The distal radius and tibia were scanned using second-generation HR-pQCT, and microstructures of trabecular and cortical bone were measured. Non-metric trabecular parameters included structure model index (SMI), trabecular bone pattern factor (TBPf), connectivity density (Conn.D), number of nodes (N.Nd/TV), degree of anisotropy (DA), and star volume of marrow space (V*ms). Estimated bone strength was evaluated by micro finite element analysis. Associations between bone microstructure, estimated bone strength, age, and menopause were analyzed. RESULTS: Trabecular number declined with age, and trabecular separation increased. SMI and TBPf increased, Conn.D and N.Nd/TV declined, and V*ms increased. Cortical BMD and thickness declined with age, and porosity increased. Stiffness and failure load decreased with age. Cortical thickness and estimated bone strength were affected by menopause. Cortical thickness was most associated with estimated bone strength. CONCLUSIONS: Trabecular and cortical bone microstructure were deteriorated markedly with age. Cortical thickness decreased after menopause and was most related to bone strength. Non-metric parameters give additional information about osteoporotic changes of trabecular bone.


Assuntos
Envelhecimento/patologia , Grupo com Ancestrais do Continente Asiático , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/patologia , Menopausa , Tomografia Computadorizada por Raios X , Absorciometria de Fóton , Adulto , Idoso , Densidade Óssea , Osso e Ossos/fisiopatologia , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/patologia , Osso Cortical/diagnóstico por imagem , Osso Cortical/patologia , Feminino , Análise de Elementos Finitos , Humanos , Japão , Modelos Lineares , Pessoa de Meia-Idade , Porosidade
8.
Chem Biol Interact ; 329: 109112, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-32360284

RESUMO

Till now monocrotophos (MCP) has been addressed as a neurotoxic stressor. Limited studies investigate its aftermath on bone pathologies. Given the fact that MCP is a propensely used insecticide in developing countries, this study investigates its potential to mirror osteoporotic features and bone loss incurred in a rodent model. Briefly, Swiss albino mice were orally gavaged daily with varying doses of MCP for 8 weeks. Musculoskeletal changes were analyzed through micro-computed tomography and histology. A series of in vitro and ex vivo cell culture experiments were performed on MC3T3E-1 and primary osteoclast cultures. Results highlight that oral gavaging with MCP causes bone loss from the cortico-trabecular interface by decreasing the osteoblast and increasing the osteoclast number. Results from in vitro studies establish that MCP treatment increases the TRAP-positive multinucleated cell number during osteoclast differentiation. Ex-vivo experiments with MCP-treated animal sera further substantiate the in vivo claims with significant decreases seen in cell viability, proliferation, mineralization and differentiation studies. In conclusion MCP induces osteoclastogenesis (bone loss) on direct stimulation and alters the circulating factors in MCP-treated serum. Holistically, this work would be of potential significance to patients suffering from pesticide induced osteoporosis.


Assuntos
Osso Esponjoso/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Osso Cortical/efeitos dos fármacos , Inseticidas/toxicidade , Monocrotofós/toxicidade , Osteogênese/efeitos dos fármacos , Animais , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/fisiologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Osso Cortical/diagnóstico por imagem , Osso Cortical/fisiologia , Masculino , Camundongos , Osteoblastos/citologia , Osteoblastos/metabolismo , Microtomografia por Raio-X
9.
Sci Rep ; 10(1): 6927, 2020 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-32332927

RESUMO

Dental implant may suffer transient external impacts. To simulate the effect of impact forces on bone damage is very important for evaluation of damage and guiding treatment in clinics. In this study, an animal model was established by inserting an implant into the femoral condyle of New Zealand rabbit. Implant with good osseointegration was loaded with impact force. A three-dimensional finite element model was established based on the data of the animal model. Damage process to bone tissue was simulated with Abaqus 6.13 software combining dynamic mechanical properties of the femur. The characteristics of bone damage were analyzed by comparing the results of animal testing with numerical simulation data. After impact, cortical bone around the implant and trabecular at the bottom of the implant were prone to damage. The degree of damage correlated with the direction of loading and the magnitude of the impact. Lateral loading was most likely performed to damage cancellous bone. The stress wave formed by the impact force can damage the implant-bone interface and peri-implant trabeculae. The data from numerical simulations were consistent with data from animal experiments, highlighting the importance of a thorough examination and evaluation based on the patient's medical history.


Assuntos
Osso e Ossos/patologia , Simulação por Computador , Implantes Dentários , Animais , Fenômenos Biomecânicos , Osso Cortical/diagnóstico por imagem , Osso Cortical/patologia , Fêmur/patologia , Fêmur/fisiopatologia , Análise de Elementos Finitos , Osseointegração , Osteogênese , Implantação de Prótese , Coelhos , Suporte de Carga , Microtomografia por Raio-X
10.
Actual. osteol ; 16(1): 26-34, Ene - abr. 2020. ilus, graf
Artigo em Espanhol | LILACS | ID: biblio-1130074

RESUMO

La expansión modeladora de la geometría cortical de un hueso inducida por su entorno mecánico podría ser difícil de modificar por estímulos ulteriores con diferente direccionalidad. Este estudio, que por primera vez combina datos tomográficos del peroné (pQCT) y dinamométricos de la musculatura peronea lateral, intenta demostrar que, en individuos jóvenes no entrenados, el entrenamiento en fútbol produce cambios geométricos peroneos expansivos, similares a los del rugby, que podrían interferir en los efectos de un entrenamiento ulterior direccionalmente diferente (carrera larga). Confirmando la hipótesis, los resultados indican, con evidencias originales, 1) la relevancia creciente del uso del pie (rotación externa y eversión provocadas por los peroneos laterales) para la determinación de la geometría peronea (incremento del desarrollo de los indicadores de masa y de diseño óseos), evidenciada por la secuencia creciente de efectos: carrera < fútbol < rugby; 2) la predominancia de esos efectos sobre el desarrollo centro-proximal del peroné para resistir a la flexión lateral, y en la región distal para resistir el buckling (principal sitio y causa de fractura del hueso) y 3.) la relevancia de la anticipación de esos efectos para interferir en la manifestación de los cambios producidos por un entrenamiento ulterior (carrera), cuando los del primero (fútbol) afectan la modelación cortical de modo expansivo. Esta última deducción demuestra, en forma inédita, que un cambio modelatorio expansivo tempranamente inducido sobre la estructura cortical ósea 'delimitaría el terreno'para la manifestación de cualquier otro efecto ulterior por estímulos de distinta direccionalidad. (AU)


The modeling-dependent, geometrical expansion of cortical bone induced by the mechanical environment could be hard to modify by subsequent stimulations with a different directionality. The current study aimed to demonstrate that in young, untrained individuals, training in soccer or rugby enhances the geometric properties of the fibula cortical shell in such a way that the geometrical changes could interfere on the effects of a second training in which the loads are induced in a different direction, e.g. long-distance running. The original findings reported herein confirm our hypothesis and support 1) The relevance of the use of the foot (external rotation and eversion produced by peroneus muscles) to determine fibula geometry (improved development of indicators of bone mass and design) as evidenced by the increasing nature of the effects induced by running < soccer < rugby trainings; 2) The predominance of those effects on the ability of the fibula to resist lateral bending in the centralproximal region (insertion of peroneus muscles), and to resist buckling in the distal region (the main cause and site of the most frequent bone fractures), and 3) The interaction of the effects of a previous training with those of a subsequent training with a different orientation of the loads when the former induced a modeling-dependent expansion of the cortex. Our results support the proposed hypothesis with original arguments by showing that a first, expansive effect induced on cortical bone modeling would set the stage the manifestation of any subsequent effect derived from mechanical stimuli. (AU)


Assuntos
Humanos , Masculino , Adolescente , Adulto , Adulto Jovem , Exercício Físico/fisiologia , Fíbula/crescimento & desenvolvimento , Corrida/fisiologia , Futebol/fisiologia , Esportes/fisiologia , Tomografia , Densidade Óssea , Fraturas Ósseas/prevenção & controle , Força Muscular/fisiologia , Dinamômetro de Força Muscular , Fíbula/diagnóstico por imagem , Osso Cortical/diagnóstico por imagem , Pé/crescimento & desenvolvimento , Pé/fisiologia , Pé/diagnóstico por imagem , Futebol Americano/fisiologia
11.
Br J Oral Maxillofac Surg ; 58(4): 427-431, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32115300

RESUMO

The aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split osteotomy (BSSO). The study including 78 consecutive patients (156 osteotomy sites). In preoperative cone-beam computed tomographic (CT) scans, the volumes of cancellous and cortical bone in the BSSO surgical field were estimated. Patients were divided into two groups based on the cancellous:cortical bone ratio. We studied postoperative cone-beam CT scans for lingual fracture lines and subcategorised them according to the lingual split scale (LSS). Generalised linear mixed models (GLMM) were estimated to evaluate the association between the cancellous:cortical bone ratio and the lingual fracture pattern. There was a significant association between the cancellous:cortical bone ratio of the mandibular angle and the lingual fracture pattern after BSSO. Mandibular angles with a relatively small amount of cancellous bone showed significantly more LSS3 fracture lines (OR=1.990, 95%CI 1.043 to 3.796, p=0.043). These mandibular angles also showed more unfavourable fractures (LSS4), although this was not significant (OR=2.352, 95%CI 0.748 to 7.392, p=0.143). The relative amount of cancellous bone in the mandibular angle is significantly associated with the lingual fracture line after BSSO.


Assuntos
Mandíbula , Osteotomia Sagital do Ramo Mandibular , Tomografia Computadorizada de Feixe Cônico , Osso Cortical/diagnóstico por imagem , Humanos , Mandíbula/diagnóstico por imagem , Mandíbula/cirurgia , Estudos Retrospectivos
12.
Arch Osteoporos ; 15(1): 50, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32193671

RESUMO

This study compares the results of computed tomography X-ray absorptiometry (CTXA) hip volumetric BMD (vBMD) analyses of cortical and trabecular bone with and without partial volume correction. For cortical bone in some circumstances, corrected cortical volumes were negative and corrected vBMD was very high. For trabecular bone, the correction effects are smaller. CTXA volumetric data should be interpreted with caution. PURPOSE: Previous studies have reported concerns about the reliability of CTXA hip cortical vBMD measurements generated using partial volume (PV) correction (the "default" analysis, with cortical PV correction). To date, no studies have examined the results of the alternative ("new") analysis (with trabecular PV correction). This study presents in vivo and phantom data comparing the corrected and uncorrected data for cortical and trabecular bone respectively. METHODS: We used the commercial QCTPro CTXA software to analyze CT scans of 129 elderly Chinese men and women and an anthropomorphic European Proximal Femur phantom (EPFP) and accessed data for two alternative scan analyses using the database dump utility. The CTXA software gives the user two methods of performing the PV correction: (1) a default analysis in which only cortical bone results are corrected; (2) a new analysis in which only trabecular bone results are corrected. Both methods are based on a numerical recalculation of vBMD values without any change in volume of interest (VOI) placement. RESULT: In vivo, the results of the two analyses for integral bone were the same while cortical and trabecular results were different. PV correction of cortical bone led to a decrease of cortical volume for all four VOIs: total hip (TH), femoral neck (FN), trochanter (TR), and intertrochanter (IT) volumes were reduced on average by 7.8 cm3, 0.9 cm3, 2.5 cm3, and 4.3 cm3 respectively. For TR, where cortex was thinnest, average corrected cortical volume was negative (- 0.4± 1.3 cm3). Corrected cortical vBMD values were much larger than uncorrected ones for TH, FN, and IT. Scatter plots of corrected cortical vBMD against cortical bone thickness showed that elevated results correlated with thinner cortices. When trabecular bone was corrected for the PV effect, trabecular volumes of TH, FN, TR, and IT were reduced on average by 7.9 cm3, 0.8 cm3, 2.6 cm3, and 4.4 cm3 respectively, while vBMD measurements were increased correspondingly. The trabecular volume and vBMD measurements of the two datasets both had highly positive correlations. For the EPFP, the PV-corrected FN data deviated from the nominal phantom value, but was closer for the TR and IT VOIs. Both corrected and uncorrected data overestimated trabecular vBMD, with the corrected results showing greater deviation from nominal values. CONCLUSION: The default and new CTXA analyses for volumetric data generate different results, both for cortical and trabecular bone. For cortical bone, the uncorrected results are subject to partial volume effects but the correction method of the default analysis overcorrects the effect leading to in part unreasonable results for cortical bone volume and BMD. For trabecular bone, the correction effects are smaller. CTXA volumetric data should be interpreted with caution.


Assuntos
Absorciometria de Fóton/estatística & dados numéricos , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/estatística & dados numéricos , Osso Cortical/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador , Absorciometria de Fóton/métodos , Idoso , Idoso de 80 Anos ou mais , China , Tomografia Computadorizada de Feixe Cônico/métodos , Feminino , Fêmur/diagnóstico por imagem , Colo do Fêmur/diagnóstico por imagem , Humanos , Masculino , Ossos Pélvicos/diagnóstico por imagem , Ossos Pélvicos/fisiopatologia , Reprodutibilidade dos Testes
13.
J Bone Miner Metab ; 38(4): 533-543, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32002681

RESUMO

INTRODUCTION: Cortical thickness of the femoral diaphysis is assumed to be a preferred parameter in the assessment of the structural adaptation by mechanical use and biological factors. This study aimed to investigate the age- and sex-specific characteristics in cortical thickness of the femoral diaphysis between young and elderly non-obese people. MATERIALS AND METHODS: This study investigated 34 young subjects (21 men and 13 women; mean age: 27 ± 8 years) and 52 elderly subjects (29 men and 23 women; mean age: 70 ± 6 years). Three-dimensional (3D) cortical thickness of the femoral diaphysis was automatically calculated for 5000-8000 measurement points using the high-resolution cortical thickness measurement from clinical CT data. In 12 assessment regions created by combining three heights (proximal, central, and distal diaphysis) and four areas of the axial plane at 90° (medial, anterior, lateral, and posterior areas) in the femoral coordinate system, the standardized thickness was assessed using the femoral length. RESULTS: As per the trends, (1) there were no differences in medial and lateral thicknesses, while the posterior thickness was greater than the anterior thickness, (2) the thickness in men was higher than that in women, and (3) the thickness in young subjects was higher than that in elderly subjects. CONCLUSIONS: The results of this study are of clinical relevance as reference points to clarify the causes of various pathological conditions for diseases of the lower extremities.


Assuntos
Osso Cortical/anatomia & histologia , Diáfises/anatomia & histologia , Fêmur/anatomia & histologia , Caracteres Sexuais , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Osso Cortical/diagnóstico por imagem , Diáfises/diagnóstico por imagem , Feminino , Fêmur/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X , Adulto Jovem
14.
J Appl Oral Sci ; 28: e20190435, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32049138

RESUMO

OBJECTIVE: To quantify the bone volume that can be safely withdrawn from 3 donor sites: (1) the mandibular symphysis, (2) the oblique mandibular line and (3) the skullcap. METHODOLOGY: For the symphysis, 200 tomographic exams were evaluated by the extension of the anterior loop of mental foramen, by the nerve, by the distance of the foramens, by the distance between the vestibular cortical and the lingual plates and by the distance between the apexes, or lower anterior teeth, and the mandibular base, using the "distance" tool of the I-CAT Vision, in the panoramic and parasagittal reformations. For the oblique line, 70 TCFC exams were analyzed retrospectively in panoramic and parasagittal reformations, evaluating the thickness of the vestibular cortical and the distance between the cortical and the mandibular canal. For the cranial bone, a hexagonal donor site located in parietal area was considered. RESULTS: The average dimensions of the bone blocks that can be safely removed from the region of the mandibular symphysis are: 32.27 mm in length, 4.87 mm in height and 4 mm in thickness, providing a volume of 628.61 mm3 available for grafting. In the oblique line, the available bone volume for grafting was 859.61 mm3. In the region of the cranial vault, multiplying the average bone thickness by the area of the hexagon, an average volume of 2,499 mm3 was obtained. CONCLUSIONS: Comparing the donor sites, the bone availability in the cranial vault is 3 times greater than in the mandibular posterior region, and at least 2 times greater than in the mandibular symphysis.


Assuntos
Transplante Ósseo/métodos , Tomografia Computadorizada de Feixe Cônico/métodos , Mandíbula/transplante , Crânio/transplante , Sítio Doador de Transplante , Adolescente , Adulto , Idoso , Pontos de Referência Anatômicos , Osso Cortical/diagnóstico por imagem , Osso Cortical/transplante , Feminino , Humanos , Masculino , Mandíbula/diagnóstico por imagem , Ilustração Médica , Pessoa de Meia-Idade , Estudos Retrospectivos , Crânio/diagnóstico por imagem , Sítio Doador de Transplante/diagnóstico por imagem , Adulto Jovem
15.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 34(2): 162-167, 2020 Feb 15.
Artigo em Chinês | MEDLINE | ID: mdl-32030945

RESUMO

Objective: CT three-dimensional reconstruction technology was used to simulate the placement of the lumbar cortical bone trajectory (CBT), to determine the starting point and direction of the screw trajectory. Methods: Between February 2017 and April 2018, 24 patients with lumbar CT were selected as the study object. There were 7 males and 17 females, with an average age of 50.4 years (range, 37-68 years). The CT DICOM data of patients were imported into Mimics 16.0 software, and the three-dimensional model of lumbar spine was established. A 5 mm diameter cylinder was set up to simulate the CBT by using Mimics 16.0 software. According to the different implant schemes, the study was divided into groups A, B, and C, the track of the screw respectively passed through the upper edge, the medial edge, and the lower edge of the isthmus of the pedicle. The intersection of simulated screw and lumbar spine was marked as region of interest (ROI) and a mask was generated. The average CT value [Hounsfield unit (HU)] and the screw length of ROI were automatically measured by Mimics 16.0 software. In addition, the head inclination angle and head camber angle of the screw were measured respectively. Point F was the intersection of the level of the lowest edge of the transverse process and the lumbar isthmus periphery. The horizontal and vertical distance between point F and the starting point were measured, and the relationship between the three schemes and the position of the zygapophysial joint and spinous process was observed. Results: Plan A has the highest ROI average HU, with the maximum value appearing in L 4; plan B has the longest screw length, with the maximum value appearing in L 5; plan C has the largest nail track head inclination angle, with the maximum value appearing in L 4; plan B has the largest nail track head camber angle, with the maximum value appearing in L 3. The screw length and head camber angle of the nail in group B were significantly greater than those in groups A and C ( P<0.05); the head inclination angle in groups A, B, and C was gradually increased, showing significant differences ( P<0.05); there was no significant difference in the average HU value of ROI between the 3 groups ( P>0.05). In plan A, 74.48% (143/192) screws had a horizontal distance of -2 to 4 mm from point F, a vertical distance of 6-14 mm from point F, a head inclination angle of (14.64±2.77)°, and a head camber angle of (6.55±2.09)°, respectively; in plan B, 84.58% (203/240) screws had a horizontal distance of 1-6 mm from point F, a vertical distance of 1-5 mm from point F, a head inclination angle of (26.93±2.21)°, and a head camber angle of (10.29±2.46)°, respectively; in plan C, 85.94% (165/192) screws had a horizontal distance of -2 to 3 mm from point F, a vertical distance of -2 to 4 mm from point F, a head inclination angle of (33.50±3.69)°, and a head camber angle of (6.47±2.48)°, respectively. Conclusion: Plan B should be selected as the starting point of the L 1-L 5 CBT implant. It is located at the intersection of the lowest horizontal line of the transverse process root and the lateral edge of the lumbar isthmus, which is 1-6 mm horizontally inward, 1-5 mm vertically upward, with a head inclination angle of (26.93±2.21)°, and a head camber angle of (10.29±2.46)°, respectively.


Assuntos
Osso Cortical , Adulto , Idoso , Parafusos Ósseos , Osso Cortical/diagnóstico por imagem , Feminino , Humanos , Imageamento Tridimensional , Vértebras Lombares , Região Lombossacral , Masculino , Pessoa de Meia-Idade , Parafusos Pediculares , Fusão Vertebral
16.
Arch Osteoporos ; 15(1): 8, 2020 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-31897775

RESUMO

A case-control study assessing the association of DXA-derived 3D measurements at lumbar spine with osteoporotic hip fractures was performed. Stronger association was found between transcervical hip fractures and integral (AUC = 0.726), and cortical (AUC = 0.696) measurements at the lumbar spine compared with measurements at the trabecular bone (AUC = 0.617); although femur areal bone mineral density (aBMD) remains the referent measurement for hip fracture risk evaluation (AUC = 0.838). PURPOSE: The aim of the present study was to evaluate the association between DXA-derived 3D measurements at lumbar spine and osteoporotic hip fractures. METHODS: We analyzed a case-control database composed by 61 women with transcervical hip fractures and 61 age-matched women without any type of fracture. DXA scans at lumbar spine were acquired, and areal bone mineral density (aBMD) was measured. Integral, trabecular and cortical volumetric BMD (vBMD), cortical thickness, and cortical surface BMD (sBMD) at different regions of interest were assessed using a DXA-based 3D modeling software. Descriptive statistics, tests of difference, odds ratio (OR), and area under the receiver operating curve (AUC) were used to compare hip fracture and control groups. RESULTS: Integral vBMD, cortical vBMD, cortical sBMD, and cortical thickness were the DXA-derived 3D measurements at lumbar spine that showed the stronger association with transcervical hip fractures, with AUCs in the range of 0.685-0.726, against 0.670 for aBMD. The highest AUC (0.726) and OR (2.610) at the lumbar spine were found for integral vBMD at the posterior vertebral elements. Significantly, lower AUC (0.617) and OR (1.607) were found for trabecular vBMD at the vertebral body. Overall, total femur aBMD remains the DXA-derived measurement showing the highest AUC (0.838) and OR (6.240). CONCLUSION: This study showed the association of DXA-derived measurements at lumbar spine with transcervical hip fractures. A strong association between vBMD at the posterior vertebral elements and transcervical hip fractures was observed, probably because of global deterioration of the cortical bone. Further studies should be carried out to investigate on the relative risk of transcervical fracture in patients with long-term cortical structural deterioration.


Assuntos
Fraturas do Colo Femoral/diagnóstico por imagem , Fraturas do Quadril/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Fraturas por Osteoporose/diagnóstico por imagem , Absorciometria de Fóton/métodos , Idoso , Densidade Óssea/fisiologia , Estudos de Casos e Controles , Osso Cortical/diagnóstico por imagem , Feminino , Fraturas do Colo Femoral/fisiopatologia , Fraturas do Quadril/fisiopatologia , Humanos , Imageamento Tridimensional , Pessoa de Meia-Idade , Fraturas por Osteoporose/complicações , Fraturas por Osteoporose/fisiopatologia
17.
Magn Reson Imaging ; 67: 85-89, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31931112

RESUMO

PURPOSE: To investigate the correlations between cortical bone microstructural properties and total water proton density (TWPD) obtained from three-dimensional ultrashort echo time Cones (3D-UTE-Cones) magnetic resonance imaging techniques. MATERIALS AND METHODS: 135 cortical bone samples were harvested from human tibial and femoral midshafts of 37 donors (61 ± 24 years old). Samples were scanned using 3D-UTE-Cones sequences on a clinical 3T MRI and on a high-resolution micro-computed tomography (µCT) scanner. TWPD was measured using 3D-UTE-Cones MR images. Average bone porosity, pore size, and bone mineral density (BMD) were measured from µCT images at 9 µm voxel size. Pearson's correlation coefficients between TWPD and µCT-based measures were calculated. RESULTS: TWPD showed significant moderate correlation with both average bone porosity (R = 0.66, p < 0.01) and pore size (R = 0.57, p < 0.01). TWPD also showed significant strong correction with BMD (R = 0.71, p < 0.01). CONCLUSIONS: The presented 3D-UTE-Cones imaging technique allows assessment of TWPD in human cortical bone. This quick UTE-MRI-based technique was capable of predicting bone microstructure differences with significant correlations. Such correlations highlight the potential of UTE-MRI-based measurement of bone water proton density to assess bone microstructure.


Assuntos
Osso Cortical/diagnóstico por imagem , Fêmur/diagnóstico por imagem , Imageamento Tridimensional/métodos , Imagem por Ressonância Magnética , Tíbia/diagnóstico por imagem , Microtomografia por Raio-X , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Densidade Óssea , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Porosidade , Prótons , Água
18.
Med. oral patol. oral cir. bucal (Internet) ; 25(1): e124-e130, ene. 2020. tab, ilus
Artigo em Inglês | IBECS | ID: ibc-196204

RESUMO

BACKGROUND: The aim of this study is to describe the presence, to reveal the frequency and characteristics of accessory canals (ACs) of the canalis sinuosus (CS) by cone beam computed tomography (CBCT). MATERIAL AND METHODS: A total of 326 CBCT examinations were scanned retrospectively. The anatomical views were evaluated on sagittal, axial, coronal and cross sectional imaging. The following parameters were recorded: age, sex, presence or absence of ACs, location in relation to the adjacent teeth and distance to the nasal cavity floor (NCF), alveolar ridge crest (ARC) and buccal cortical bone (BCB), and incisive canal. All the collected data were statistically analyzed. RESULTS: 113 patients (34,7%); presented ACs in total 214 foramina of the sample. There were no statistically sig-nificant changes in the presence of ACs regarding age groups excluding 80-89 years. But there is a statistically significant difference regarding the frequency of ACs and the gender. The prevalence for male patients was higher than female patients. Curved-shape configuration of CS prevalence is found as 69,15%. The prevalence of vertical tracing is 26,16% and Y-shape configuration of CS prevalence is 4,67%. Diameter of the foramens of the CS branches was 1.30 mm. The mean distance of the AC to the NCF, BCB, and ARC were found 13,83 mm, 6,60 mm and 5,32 mm, respectively. CONCLUSIONS: In the anterior palatal region, ACs are mostly related to CS's branches. So; knowing the course of CS branches in surgical planning and radiographic evaluations in this region is extremely important for preventing complications and avoiding misdiagnosis


No disponible


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Maxila/anatomia & histologia , Maxila/diagnóstico por imagem , Nervo Maxilar/anatomia & histologia , Nervo Maxilar/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico/métodos , Osso Cortical/anatomia & histologia , Osso Cortical/diagnóstico por imagem , Cavidade Nasal/anatomia & histologia , Cavidade Nasal/diagnóstico por imagem , Fatores Etários , Fatores Sexuais , Padrões de Referência , Pontos de Referência Anatômicos , Estudos Retrospectivos
19.
J Endod ; 46(2): 169-177.e1, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31839413

RESUMO

INTRODUCTION: Limited field of view cone-beam computed tomography (LFOV CBCT) is the primary imaging modality recommended for treatment planning before endodontic microsurgery (EMS). Persistent apical periodontitis, often treated with EMS, results in changes in the buccal cortical plate that may detrimentally impact prognosis. The accuracy of a preoperative LFOV CBCT to predict intraoperative findings is unclear. METHODS: Electronic health records (EHRs) of EMS performed at 2 endodontic offices between 2016 and 2018 were reviewed retrospectively. EHR data extracted were documented for surgical findings of intact buccal cortical plate, fenestration, dehiscence, and height of remaining buccal collar of bone. Two calibrated, independent reviewers evaluated presurgical LFOV CBCTs in the multiplanar paraxial and parasagittal planes at 2 different reconstructed viewing plane thicknesses. Reviewer findings were compared with EHR documentation. Data were analyzed by using χ2, logistic regression, and multivariable analysis. Significance was set at P < .05. RESULTS: Within the 125 EMS cases included in the study, the EHR prevalence of intact buccal cortical plate was 49%, dehiscence 7%, and fenestration 44%. The imaging predictive value, whether it was negative (NPV) or positive (PPV), was higher when predicting presence of buccal bone (PPV of intact buccal cortical plate = 86.5%; NPV of dehiscence = 96%; NPV of fenestration = 89%). Sensitivity and specificity ranged from 80%-90%. Accuracy in prediction was high for all variables, exceeding 80%. Accuracy was not significantly influenced by reconstructed viewing slice thickness, viewing plane, or reviewer. CONCLUSION: Preoperative LFOV CBCT was highly discriminatory and accurately predicted intraoperative buccal cortical bone status, especially intact buccal cortical plate and fenestration.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Microcirurgia , Osso Cortical/diagnóstico por imagem , Humanos , Estudos Retrospectivos
20.
Acta Orthop ; 91(1): 1-75, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31801400

RESUMO

Background and purpose - Most guidelines use patient age as a primary decision factor when choosing between osteosynthesis or arthroplasty in displaced femoral neck fractures. We evaluate reoperation and death risk within 1 year after osteosynthesis, and estimate the influence of age, sex, degree of displacement, and bone quality.Patients and methods - All surgeries for femoral neck fractures with parallel implants (2 or 3 screws or pins) performed between December 2011 and November 2015 were collected from the Danish Fracture Database. Radiographs were analyzed for initial displacement, quality of reduction, protrusion, and angulation of implants. The bone quality was estimated using the cortical thickness index (CTI). Garden I and II type fractures with posterior tilt < 20° were excluded.Results - 654 patients with a mean age of 69 years were included. 59% were female. 54% were Garden II with posterior tilt > 20° or Garden III, and 46% were Garden IV. Only 38% were adequately reduced. 19% underwent reoperation and 18% died within 12 months. Female sex, surgical delay between 12 and 24 hours vs. < 12 hours, Garden IV type fracture, inadequate reduction, and protrusion of an implant were associated with statistically significant increased reoperation risk. No significant association between reoperation and age, CTI, or the initial angulation of implants was found. Notably, CTI was linked inversely with death risk.Interpretation - Reoperation risk is linked mainly to primary displacement and reduction of the fracture, with no apparent effect of age or bone quality. Bone quality may be linked with risk of death.


Assuntos
Osso Cortical/patologia , Fraturas do Colo Femoral/cirurgia , Fixação Interna de Fraturas/métodos , Fixação de Fratura/métodos , Mortalidade , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Artroplastia de Quadril , Estudos de Coortes , Osso Cortical/diagnóstico por imagem , Dinamarca , Feminino , Fraturas do Colo Femoral/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Modelos de Riscos Proporcionais , Reoperação/estatística & dados numéricos , Risco , Fatores Sexuais , Tempo para o Tratamento , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...