Search results for "Bone Screws"

A Novel Technique Using Polytetrafluoroethylene Tape to Solve Screw Loosening Complication in Implant-Supported Single Crowns

2020

This study aimed to analyze a novel technique to make screws with greater untightening resistance and to solve screw loosening in implant-supported single crowns. Thirty grade IV titanium straight abutments were screwed onto 30 external hex implants using grade IV titanium screws (30 Ncm). They were exposed to cyclic loading (300,000 cycles, 200 N). Samples were divided into 4 groups (15 samples per group): new screws (SCREW group) (control), reused screws (rSCREW group), new screws wrapped with polytetrafluoroethylene (PTFE) tape (PTFE group), and reused screws wrapped with PTFE tape (rPTFE group). Reverse torque values (RTVs) were recorded with a digitally calibrated implant motor. Mean R…

Retrograde nailing versus locking plate osteosynthesis of proximal humeral fractures: a biomechanical study

2011

Background In locking plate osteosynthesis of proximal humeral fractures, secondary varus malalignment is a specific complication. Retron nails (Tantum AG, Neumunster, Germany), among others, have been designed to improve medial support of the calcar humeri. The aim of our biomechanical study was to examine whether Retron nails provide increased stiffness for axial loads and adequate stiffness for torsional loads when compared with Philos plates (Synthes AG, Umkirch, Germany). Materials and methods Twenty-two fresh-frozen paired humeri were collected. After potting the specimens, intact bones were exposed to sinusoidal axial (10-120 N) and torsional (±2.5 Nm) loading for 8 cycles to calcula…

Volar and dorsal mid-shaft forearm plating using DCP and LC-DCP: interference with the interosseous membrane and forearm-kinematics.

2010

Purpose To clarify if dorsal plate osteosynthesis of the forearm shaft is associated with impingement of the interosseous membrane (IOM) and if rotational kinematics of the forearm are influenced. Background Forearm fractures are treated by separate incisions. Osteosynthesis via one approach in proximal forearm fractures was associated with higher rates of synostosis. It has been claimed that this is due to IOM impingement. Materials and methods 16 forearms of fresh frozen cadavers were dissected until only radius, ulna and the IOM remained. To preserve physiological forearm rotation, the elbow joint, the distal radio-ulnar joint and the carpus remained intact. In group 1, LC-DC and DC plat…

Navigated percutaneous screw fixation of the pelvis with O-arm 2: two years' experience.

2020

Aim To evaluate the case series of the patients operated with percutaneous fixation by the navigation system based on 3D fluo-roscopic images, to assess the precision of a surgical implant and functional outcome of patients. Methods A retrospective study of pelvic ring fractures in a 2-year period included those treated with the use of the O-Arm 2 in com-bination with the Stealth Station 8. Pelvic fractures were classifi-ed according to the Tile and the Young-Burgess classification. All patients were examined before surgery, with X-rays and CT scans, and three days after surgery with additional CT scan. The positioning of the screws was evaluated according to the Smith score, the outcome wi…

Effectiveness of interceptive treatment of class III malocclusions with skeletal anchorage: A systematic review and meta-analysis

2017

Recently, new strategies for treating class III malocclusions have appeared. Skeletal anchorage appears to reduce the dentoalveolar effects while maximising the orthopaedic effect in growing patients. The purpose of this systematic review and meta-analysis is to examine the effectiveness of bone anchorage devices for interceptive treatment of skeletal class III malocclusions. Searches were made in the Pubmed, Embase, Scopus and Cochrane databases, as well as in a grey literature database, and were complemented by hand-searching. The criteria for eligibility were: patients who had undergone orthodontic treatment with skeletal anchorage (miniplates and miniscrews). Patients with syndromes or …

Learning Curve in Surgical Treatment of Odontoid Fixation for a Series of Type II C2 Fractures

2019

The craniovertebral junction (CVJ) is a complex anatomical area upon which most of the motion of the upper cervical spine depends [1]. Because of its unique range of motion, the CVJ is subject to several types of traumatic injury; it has been shown that odontoid fractures are the most common ones in the general population and are the most common isolated spinal fractures [2]. Accounting for up to 18% of all cervical fractures, odontoid fractures are the most common ones in elderly patients [3], in whom they account for up to 60% of spinal cord injuries [4].

Screw fixation of radial head fractures: Compression screw versus lag screw—A biomechanical comparison

2009

Abstract Introduction Secondary loss of reduction and pseudarthrosis due to unstable fixation methods remain challenging problems of surgical stabilisation of radial head fractures. The purpose of our study was to determine whether the 3.0 mm Headless Compression Screw (HCS) provides superior stability to the standard 2.0 mm cortical screw (COS). Materials and methods Eight pairs of fresh frozen human cadaveric proximal radii were used for this paired comparison. A standardised Mason II-Fracture was created with a fragment size of 1/3 of the radial head's articular surface that was then stabilised either with two 3.0 mm HCS (Synthes) or two 2.0 mm COS (Synthes) according to a randomisation …

A new concept to treat lumbar spine stenosis in a mini invasive way.

2017

Transverse fracture-dislocation of the sacrum: a diagnostic pitfall and a surgical challenge.

2002

Transverse fracture-dislocations of the sacrum are rare. Associated lesions of the lumbosacral spine as well as neurological injuries are common. Conventional radiographs of the pelvis often fail to clearly visualize the fracture. Delayed diagnosis increases the risk of progressive neurological disfunction. True lateral sacral views and CT-scans with 3-dimensional reconstructions are very helpful in establishing the full extent of the injury. These examinations should be considered in all patients with a history of high energy trauma and clinical signs indicating lumbosacral injury, such as severe low back pain and neurological disturbances of the lower extremities. The management of transv…

In vitro comparison of the efficacy of two fractured implant-prosthesis screw extraction methods: Conventional versus mechanical.

2019

Abstract Statement of problem Implant-supported prostheses may be subject to esthetic, biological, or mechanical complications. Protocols for dealing with these mechanical problems are sparse. Purpose The purpose of this in vitro study was to compare the efficacy of a mechanical system for extracting fractured implant-prosthesis screws with the conventional method. Material and methods A total of 60 screws were divided into 2 groups according to their morphology (flat screws with a smooth shaft and threaded apical area and screws with a completely threaded body) and subjected to fatiguing and static load testing until fracture. The specimens were assigned to 3 operators with varying levels …