Search results for "Fracture"
showing 10 items of 873 documents
Failure of ProTaper rotary Ni-Ti instruments used by undergraduate students
2012
Objective: To evaluate the effect of number of uses, angle and radius of curvature and type of instrument on the fracture of ProTaper rotary instruments when used by undergraduate students. Study Design: Three hundred and seventy-six molars, with a total of 1114 root canals, extracted were instrumented by undergraduate students using ProTaper instruments according to the manufacturer´s recommendations. When fracture occurred, data were collected concerning the number of uses, type of instrument, level of fracture, angle and radius of curvature. ANOVA test were used to determine the influence of type of instrument in the incidence of instrument fracture. Logistic regression model was used to…
Seltener Fall einer Femurkopfkalottenfraktur
1990
Sind winkelstabile Plattensysteme mit elastischen Eigenschaften für die Stabilisierung der Oberarmkopffraktur vorteilhaft? / Eine in-vitro biomechani…
2004
AbstractWinkelstabile Platten werden mit zunehmender Häufigkeit zur Stabilisierung von Oberarmkopfbrüchen verwendet. Rigide Implantate führen bei osteoporotischen Knochenverhältnissen u. U. aber häufiger zum Versagen. Um den Effekt der Implantatelastizität zu beurteilen wurden in einer in-vitro Studie die biomechanischen Eigenschaften eines rigiden und eines elastischen winkelstabilen Plattensystems vergleichend analysiert. An 8 Humeruspaaren wurde eine instabile subkapitale Fraktur simuliert. Die Proben wurden axial- und torsions-belastet. Analysiert wurden die Steifigkeit, das Setzverhalten unter Dauerlast und die Versagensbelastung.Das elastische Plattensystem kennzeichnete sich durch ei…
Dynamische Analyse von Osteosynthesen am Olecranon: ein in-vitro Vergleich zweier Osteosynthesesysteme / Dynamic analysis of olecranon osteosyntheses…
2008
INTRODUCTION The aim of the present study was to develop a test setup with continuous angle alteration to imitate elbow joint motion for the mechanical evaluation of tension band wiring and a newly designed intramedullary nail. MATERIALS AND METHODS The servo-pneumatical test stand worked with a rotational angle-adjusted and a linear force-adjusted engine. The fracture model was dynamically tested under cyclic loading imitating elbow joint motion. In total, 14 fresh cadaver upper extremities underwent olecranon fracture by means of transverse osteotomy and were assigned to two groups: tension band wiring and intramedullary nailing. There was a continuous angle alteration between 0 and 1000 …
In-vitro fatigue and fracture performance of three different ferrulized implant connections used in fixed prosthesis
2021
Background/purpose: The aim of the present in vitro study was to evaluate fatigue resistance of dental fixtures in three different types of fixture/abutment finishing line. Materials and methods: Transmucosal dental implants, with or without ferrulized neck, underwent fatigue tests (static and dynamic load) using the following standard protocol: UNI EN ISO 14801:2016. Two types of loading devices (screw- or cement-retained restoration) were also tested, and fatigue cycle tests were run to failure. Data of static and dynamic load tests were analyzed by proper statistical methods. Results: Following standard protocol for fatigue testing, the ILC type (Implant Level with ferrulized neck and ce…
Biomechanical Study of the Osteoporotic Spine Fracture: Optical Approach
2021
Background and objectives: Osteoporotic spine fractures represent a significant factor for decreasing quality of life in the elderly female population. Understanding the mechanisms involved in producing these fractures can improve their prevention and treatment. This study presents a biomechanical method to produce a vertebral fracture, conducted on a human spine segment, observing the displacements and strains in the intervertebral disc, endplate, and vertebral body. Materials and Methods: We performed two tests, one corresponding to an extension loading, and the second to an axial loading. Results: The maximum displacement in the target vertebral body presented higher values in the case o…
Etiology, Modalities of Zygomaticomaxillary Complex Fracture, open reduction and fixation.
2020
Background Zygomatic complex fracture is second most common mid face fracture and frequent amongst the maxillofacial trauma. Fracture pattern ranges from simple to comminuted and from minimally displaced to severely displaced depending on various factors. Material and methods 98 patients with zygomaticomaxillary complex fracture reporting during December 2017 to January 2020 were included in the study. On the basis of radiographic evaluation and computerized tomography scan (CT scan) with 3D reconstruction severity of fracture was assessed and different treatment options were selected. Results Road traffic accident accounted as the leading cause of fracture (57.1%) followed by self-fall (16…
Osteosynthese am proximalen Humerus mittels winkelstabiler Platte oder Doppelplatte: eine vergleichende biomechanische Untersuchung / Angle-fixed pla…
2008
Internal fixation of fractures of the proximal humerus needs a high stability of fixation to avoid secondary loss of fixation. This is especially important in osteoporotic bone. In an experimental study, the biomechanical properties of the angle-fixed Philos plate (internal fixator) and a double-plate osteosynthesis using two one-third tubular plates were assessed. The fracture model was an unstable three-part fracture (AO type B2). Eight pairs of human cadaveric humeri were submitted to axial load and torque. In the first part of the study, it was assessed to which degree the original stiffness of the humeri could be restored after the osteotomy by the osteosynthesis procedure. Subsequentl…
Photoelastic analysis of conventional and locking system for treatment of mandibular angle fractures with a single plate
2021
Made available in DSpace on 2021-06-25T10:28:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Background: This photoelastic analysis evaluated stress distribution in different osteosynthesis systems, conventional and locking, used for treatment of mandibular angle fractures with a single plate. Material and Methods: Angle fractures were simulated in mandibles made of photoelastic resin. Following Champy’s method, plate osteosynthesis was performed. The samples were divided into five groups: Group 1, non-fractured mandible; Group 2, two screws were installed in each segment using a conventional system; Group 3, two screws were installed in each segment using a locking system; …
Bone remodeling in malunited fractures in children. Is it reliable?
1997
Fracture malunion is not a rare phenomenon in children due to the frequent use of closed reduction treatments. In this article, the processes of bone remodeling in cases of angular and rotational deformities, overriding of bone fragments, and overgrowth are addressed. Critical analyses of the mechanisms to correct these deformities, function of the physis and periosteum, and other related factors are given. The acceptable deformities for complete remodeling to be successful vary at different ages and locations.