Acute intraoperative reactions during the injection of calcium sulfate bone cement for the treatment of unicameral bone cysts: a review of four cases.
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Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided. (+info)
Index of Complexity, Outcome and Need scored on plaster and digital models.
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Influence of irradiation conditions on the deformation of pure titanium frames in laser welding.
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Due to its ease of use in connecting metal frames, laser welding is now applied in dentistry. However, to achieve precise laser welding, several problems remain to be resolved. One such problem is the influence of irradiation conditions on the deformation of titanium frameworks during laser welding, which this study sought to investigate. Board-shaped pure titanium specimens were prepared with two different joint types. Two specimens were abutted against each other to form a welding block with gypsum. For welding, three different laser waveforms were used. Deformation of the specimen caused by laser welding was measured as a rise from the gypsum surface at the opposite, free end of the specimen. It was observed that specimens with a beveled edge registered a smaller deformation than specimens with a square edge. In addition, a double laser pulse waveform--whereby a supplementary laser pulse was delivered immediately after the main pulse--resulted in a smaller deformation than with a single laser pulse waveform. (+info)
Properties of a gypsum-bonded magnesia investment using a K2SO4 solution for titanium casting.
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The purpose of the study was to investigate the effects of a K2SO4 solution on the improvement of the properties of an experimental magnesia-based gypsum-bonded investment. The characteristics of the experimental investment with different ratios of a K2SO4 solution were as follows: setting time ranged from 34 to 152 minutes, green and fired compressive strengths were approximately 2.15 to 5.81 MPa and 1.63 to 2.45 MPa, respectively; thermal expansion was 0.38 to 0.47% at 700 degrees C, which did not show any significant differences due to the concentration of the K2SO4 solution. Titanium casting could be obtained using the experimental investment mixed with a 1% K2SO4 solution, and the reaction layer thickness of the casting was less than 200 microm. The results suggest that the experimental investment mixed with 1% K2SO4 showed acceptable physical properties and casting characteristics for titanium casting. (+info)