Magnetic Field Interactions of Orthodontic Wires during Magnetic Resonance Imaging (MRI) at 1.5 Tesla

AbstractBackground: Orthodontic appliances pose a potential risk during magnetic resonance imaging (MRI) due to forces on metallic objects within the static magnetic field of MRI systems. The aim of the present investigation was to measure forces on orthodontic wires caused by the static magnetic field of a 1.5-Tesla MRI system, and to assess the safety hazards associated with these forces.Materials and Methods: Thirty-two different orthodontic wires (21 arch wires, eight ligature wires and three retainer wires) were investigated in a 1.5-Tesla MRI system (Magnetom Symphony, Siemens Medical Solutions, Erlangen, Germany). The translational forces were measured using the deflection angle test (ASTM F2052-02); rotational forces were assessed on a 5-point qualitative scale.Results and Conclusion: All retainer wires and the steel arch wires (the Noninium^® arch wire being the exception) were subjected to considerable rotational and translational forces within the MRI system’s magnetic field. Translational forces were from 9.1- to 27.6-times as high as gravitational forces on these objects. Steel ligature wires and arch wires made of cobalt chromium, titanium molybdenum, nickel-titanium, and brass alloys showed no or negligible forces within the magnetic field. The translational and rotational forces within the MRI magnetic field should pose no risk to carefully-ligated arch wires. Steel retainer wire bonds should be checked to ensure secure attachment prior to an MRI investigation.* both authors share first authorship     

Evaluation of occlusal splint therapy and relaxation procedures in patients with temporomandibular disorders

Twenty-four patients were selected to participate in this study. Twelve patients were randomly selected to receive occlusal splint therapy and the other 12 to receive a simplified relaxation therapy technique. Observable pain scores, maximum comfortable interincisal distance, and maximum interincisal distances were recorded for each group before and after treatment. The occlusal splint group showed a significant decrease in total mean observable pain scores (decrease score of 10.5, t = 3.124; P less than 0.1). The relaxation group showed no significant decrease in total mean observable pain scores (decrease score of 1.8, t = 0.888; P = ns). The occlusal splint group showed a significant increase in the mean maximum comfortable opening (an increase of 12.4 mm, t = 5.085; P less than .01). The relaxation group showed no significant increase in the mean maximum comfortable opening (an increase of 2.3 mm, t = 0.734; P = ns). The occlusal splint group showed a significant increase in the mean maximum opening (an increase of 6.0 mm, t = 2.471; P less than .05). The relaxation group showed no increase in the mean maximum opening (decrease of 0.7 mm, t = 0.343; P = ns). This study suggests that occlusal splint therapy is a more effective treatment for the pain, tenderness, and limited mandibular opening associated with temporomandibular disorders than relaxation therapy. In this study, the relaxation technique used had no significant effect on the patients' pain, tenderness, or limited opening.     

Idiopathic ileoileal intussusception in an adult with spontaneous reduction during enteroclysis: a case report

We report a rare case of recurring idiopathic ileoileal intussusception in an adult. Diagnosis was established with abdominal computed tomography (CT) and enteroclysis, which led to a spontaneous reduction of the invagination. After a short period of physical improvement, a follow-up CT showed a recurrence. Surgery proved the diagnosis, but no predisposing factor was found.     

Beobachtungen über die Wirkung von Insektenstichen

Ohne ZusammenfassungMit 6 Textabbildungen.     

A new heparin fragment decreases liver ischemia-reperfusion injury

<正>To the Editor:Ischemia-reperfusion injury following surgery and transplantation can lead to irreversible multiorgan failure.Intracellular calcium overload is associated to cellular death during ischemiareperfusion.A recently discovered heparin fragment (HF),trisulfated disaccharide (TD),that acts on sodium-calcium exchanger(NCX) decreasing intracellular Ca²⁺,showed effectiveness on protecting hepatocytes from ischemia-reperfusion injury [1],     

Low-level echogenicity in intraventricular hemorrhage versus ventriculitis

Serial cranial sonograms of 55 neonates with large perinatal intraventricular/intraparenchymal hemorrhages and moderate-to-severe posthemorrhagic hydrocephalus were reviewed. In all 55 patients, the ventricles were initially enlarged and filled with anechoic cerebrospinal fluid, which contained discrete hyperechoic fragments of hematoma. Between 7 and 25 days after the initial hemorrhagic episode, however, diffuse, low-level echogenicity appeared in the ventricles of 34 patients. The low-level echogenicity was transient and persisted for 7-59 days (average, 18 days). In 32 patients, low-level echogenicity was a benign finding associated with prior intraventricular hemorrhage. In two patients, the low-level echogenicity was associated with ventriculitis. Low-level echogenicity appeared, increased, then cleared, but reappeared with the onset of ventriculitis in these two patients. Thickening of the ependyma and abnormal periventricular echogenicity, signs of inflammation, were also present. Although low-level echogenicity may commonly be a benign finding, the possibility of ventriculitis should not be ignored.