Search results for "Fracture"
showing 10 items of 873 documents
Flow and fracture of materials according to a new limiting condition of yelding
1967
In general the theories on “conditions of plastification” known up till now (Tresca, v. Mises, and others) have only taken into consideration the characteristics of resistance to simple tension and compression, when dealing with structures called upon to resist mainly to tension and compression respectively, without taking into account the inherent resistance to tension and compression respectively of the material employed; this contributory factor is particularly important, especially where the exigencies are very considerable. The theory that we are about to consider has been largely confirmed in the experimental field. Applications to the study of hollow cylinders and hollow spheres serv…
Postmenopausal women with osteopenia and a healed wrist fracture have reduced physical function and quality of life compared to a matched, healthy co…
2014
Background: Fractures lead to reduced physical function and quality of life (QOL), but little is known about postmenopausal women with osteopenia and a healed wrist fracture. The purpose was to evaluate physical function in terms of quadriceps strength, dynamic balance, physical capacity and QOL in postmenopausal women with osteopenia and a healed wrist fracture compared to a matched, healthy control group with no previous fracture. Methods: Eighteen postmenopausal women with osteopenia (patients) (mean age 59.1 years, range 54 – 65) and a healed wrist fracture were matched to 18 healthy control subjects on age (mean age 58.5 years, range 51 – 65), height, weight and body mass index (BMI). …
Difficulties in distinguishing between an atlas fracture and a congenital posterior atlas arch defect in postmortem analysis.
2013
We found one atlas from a sample of 148 skeletons (0.67%) that presented different anatomical variations which made it difficult to determine whether the vertebra had an atlas fracture, an unusual Type B posterior atlas arch defect, or a combination of both. We carried out a stereomicroscopy, radiographic, and computerized tomography scan study that revealed that the dry atlas we found presented a very uncommon congenital Type B posterior atlas arch defect, simulating a fracture. In short, the present paper has revealed that differentiating Type B posterior atlas arch defects from fractures in post-mortem dry vertebrae is more difficult than expected. Thus we believe that it can be easier t…
Incidence and predictive factors for perforation of the maxillary antrum in operations to remove upper wisdom teeth: prospective multicentre study.
2006
Our aim was to evaluate the incidence of perforations of the sinuses and their related treatment after the removal of upper wisdom teeth depending on various anatomical and clinical variables.A total of 1057 upper wisdom teeth were removed under local anaesthetic in the departments of oral surgery at the Universities of Bonn, Düsseldorf, Frankfurt and Mainz, Germany. Data were collected with the help of an anonymised questionnaire dealing with information about the patients, and the position and stage of the development of teeth, as well as the occurrence and size of an oro-antral communication and its treatment.Of 465 extractions and 592 osteotomies of the upper third molars, 134 intervent…
Coronectomy - An alternative approach to remove impacted teeth in oncological patients.
2018
Background Coronectomy involves the section of the tooth crown leaving the roots in the socket. Possibility of inferior alveolar nerve injury and mandibular fracture are the main indications for this approach. Herein, we describe a case series of coronectomy to highlight its indication in normal and oncological patients. Material and methods A total of 9 patients were submitted to coronectomy, 6 of them were oncological. Three patients were evaluated before head and neck radiotherapy (HNRT), 2 after HNRT and 1 before bone marrow transplantation. Results Mean age of the patients was 49 years, most of them male (n=7). Lower third molars were the main teeth that received this procedure, and al…
Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations
2020
Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 ×
Association between eruption state of the third molar and the occurrence of mandibular angle fractures.
2015
Background/Aim Fractures of the mandible, especially the mandibular angle, are one of the most frequent types of injuries of the facial skeleton. In many cases, a retained third molar can be found in the line of the fracture. However, it remains unclear whether a relationship between third molars and mandibular angle fractures exists. Materials and Methods Patients with isolated or combined fractures of the lower jaw between January 2001 and December 2007 were analyzed retrospectively. Electronic health records were investigated regarding the types of mandibular fractures, and panoramic radiographs were reviewed concerning the existence of third molars. In addition, a systematic review was …
Do third molars weaken the mandibular angle?
2010
Objective: The purpose of this study is to estimate how is the magnitude of the impact of a mandibular third molar on the mandibular angle stiffness. Study Design: It was performed a literature search on whole MEDLINE and LILACS data base to find articles that match the following inclusion criteria: cohort studies presenting data on patients with mandibular fractures and third molars; that had a similar angle fracture definition; and that present data available to be cross-classified in a statistic analysis. Results: The sample was composed by 4 studies, involving 2533 patients from USA, Nigeria, Germany and Jordan, evaluated between 1976 and 2001. The analysis of the sample shows a relativ…
Natural micro-scale heterogeneity induced solute and nanoparticle retardation in fractured crystalline rock.
2011
Abstract We studied tracer (Tritiated Water (HTO); Tritium replaces one of the stable hydrogen atoms in the H 2 O molecule) and nanoparticle (quantum dots (QD)) transport by means of column migration experiments and comparison to 3D CFD modeling. Concerning the modeling approach, a natural single fracture was scanned using micro computed tomography (μCT) serving as direct input for the model generation. The 3D simulation does not incorporate any chemical processes besides the molecular diffusion coefficient solely reflecting the impact of fracture heterogeneity on mass (solute and nanoparticles) transport. Complex fluid velocity distributions (flow channeling and flowpath heterogeneity) evo…
Development of crystal morphology during unitaxial growth in a progressively widening vein: II. Numerical simulations of the evolution of antitaxial …
2001
The development of fibrous morphology and capability of fibres for tracking the opening trajectory were investigated using numerical simulations of a natural antitaxial fibrous vein. Starting from a non-unique best case, variation of fracture opening velocity, grain size, wall roughness, growth anisotropy and crystal growth velocity shows that these parameters differ in importance for crystal morphology and tracking capability. Fibrous veins can be simulated using crack–seal opening of the fracture. Grain boundaries track the opening trajectory if the wall roughness is high, opening increments are small and crystals touch the wall before the next crack increment starts.