Search results for "Orthodontics."
showing 10 items of 920 documents
Load Distribution in the Lumbar Spine During Modeled Compression Depends on Lordosis.
2021
Excessive or incorrect loading of lumbar spinal structures is commonly assumed as one of the factors to accelerate degenerative processes, which may lead to lower back pain. Accordingly, the mechanics of the spine under medical conditions, such as scoliosis or spondylolisthesis, is well-investigated. Treatments via both conventional therapy and surgical methods alike aim at restoring a “healthy” (or at least pain-free) load distribution. Yet, surprisingly little is known about the inter-subject variability of load bearings within a “healthy” lumbar spine. Hence, we utilized computer tomography data from 28 trauma-room patients, whose lumbar spines showed no visible sign of degeneration, to …
The influence of lateral release on patello-femoral joint loading in knee arthroplasty
1992
Eight fresh, cadaveric knees have been fitted with four different total knee cemented prostheses. Loading forces at the bone implant fixation interface of the patella component have been measured in a knee joint testing rig by four miniaturized force transducers, before and after a lateral release of the patellar retinaculum. The lateral release resulted in a significant local force reduction in the lateral and/or proximal quadrant of the patella resection plane depending on the knee flexion angle, quadriceps tensile force direction, and the patellar prosthesis design.
Maxillary bone lesions in McCune-Albright syndrome:a case report
2011
Abstract Objectives In this study, we report on the clinical maxillary manifestations of a patient affected by McCune-Albright syndrome and the implications for orthodontic therapy. Materials and methods A male, 8-year-old patient was examined at the Department of Orthodontics of the University of L’Aquila for a problem of anterior open-bite. In the clinical examination, a small swelling of the left hemi-maxilla was seen in the area corresponding to the root apex of 16 and under the tooth buds of 14 and 15. In a panoramic radiograph, a radio-opaque area was detected in this zone. From the computer tomography examination, a bone lesion was identified. Results Identification of this bone lesi…
A Locked Intraosseous Nail for Transverse Patellar Fractures: A Biomechanical Comparison with Tension Band Wiring Through Cannulated Screws.
2018
Background Displaced transverse patellar fractures require open reduction and internal fixation. State-of-the-art stabilization techniques are tension band wiring (TBW) using Kirschner wires or cannulated screws. These techniques are associated with high rates of secondary fracture displacement, implant migration, implant prominence, wound-healing disturbances, and the need for implant removal. Recently, a locked intraosseous patellar nail prototype was developed. The aim of the present study was to investigate the biomechanical performance of this nail compared with TBW using cannulated screws. Methods Seven paired fresh-frozen human cadaveric knees were stripped of all soft tissues except…
Influence of the Screw Positioning on the Stability of Locking Plate for Proximal Tibial Fractures: A Numerical Approach
2020
Tibial fractures are common injuries in people. The proper treatment of these fractures is important in order to recover complete mobility. The aim of this work was to investigate if screw positioning in plates for proximal tibial fractures can affect the stability of the system, and if it can consequently influence the patient healing time. In fact, a more stable construct could allow the reduction of the non-weight-bearing period and consequently speed up the healing process. For that purpose, virtual models of fractured bone/plate assemblies were created, and numerical simulations were performed to evaluate the reaction forces and the maximum value of the contact pressure at the screw/bo…
Comparison of frictional resistance between passive self-ligating brackets and slide-type low-friction ligature brackets during the alignment and lev…
2019
Background To compare the frictional resistance between passive self-ligating brackets and conventional brackets with low-friction ligature under bracket/archwire and root/bone interface during dental alignment and leveling. Material and methods A tridimensional model of the maxilla and teeth of a patient treated with conventional brackets, and slide ligatures was generated employing the SolidWorks modeling software. SmartClip self-ligating brackets and Logic Line conventional brackets were assembled with slide low-friction ligatures, utilizing archwires with different diameters and alloys used for the alignment and leveling stage. Friction caused during the bracket/archwire interface and s…
Dynamic Gait Parameters in Patients With Nonunion of the Tibia Following Treatment With the Ilizarov Method.
2020
Abstract The purpose of this study was a comprehensive assessment of the dynamic parameters of gait in patients who underwent Ilizarov treatment for nonunion of the tibia. The experimental group consisted of 24 individuals treated with the Ilizarov method for nonunion of the tibia. The control group comprised 31 healthy individuals, matched for BMI, sex, and age. The dynamic gait parameters in patients and in the control group were measured with a Zebris pedobarographic platform. The treatment group and the control group showed statistically significant differences in terms of the following gait parameters: maximum force during braking nonoperated-limb (NOL), time maximum force during braki…
MRI evaluation to predict tendon size for knee ligament reconstruction.
2017
Background The aim of this study is to evaluate a possible correlation between specific anthropometric parameters and sizes of knee tendons commonly used for ACL reconstruction. We hypothesized that specific clinical and radiological knee measurements could be better tendon sizes predictors than age, gender, height and weight. Materials and methods 100 consecutive patients were enrolled and 77 patients met the inclusion criteria of the study. All patients underwent a MRI of the knee with a 1.5 T super conducting MR System. For each patient, anthropometric data such as gender, height, weight, body mass index (BMI) and knee circumference were recorded. Specific MRI knee measurements were perf…
Radial Head Fractures
2014
Radial head fractures are the most common elbow fractures, accounting for 20–30 %. Typically, the fractures evolve from a fall on the outstretched hand with the elbow extended and the forearm in pronation. The role of the radial head as an important stabilizer of the elbow joint has been recognized in the last decade. Sixty percent of the axial load transmitted through the elbow is conducted through the radial head. Furthermore, the radial head is an important stabilizer against valgus stresses. While the medial collateral ligament (MCL) is the primary stabilizer against valgus stress, the role of the radial head emerges when the MCL is torn. These findings have led to a change in treatment…
Iliosacral Screw Osteosynthesis
2017
Fragility fractures of the anterior pelvic ring are very often combined with fractures of the posterior pelvic ring. The large majority of the posterior fractures is situated in the sacral ala. Non-operative therapy may be cumbersome in patients with a combination of an anterior with a posterior pelvic ring fracture. Any surgical therapy should be as less invasive as possible. Iliosacral screw fixation is a minimal invasive technique. Variations of the upper sacral anatomy make optimal iliosacral screw placement challenging. The vestibule or isthmus is the narrowest part of the bony corridor from the lateral ilium to the S1 sacral body. It always points towards anterior and superior. The wh…