Comparison of the shear bond strength of brackets in regards to the light curing source / 대한치과교정학회지

With the introduction of the xenon plasma arc curing light and the LED curing light as orthodontic curing lights, the polymerizing time of orthodontic composites has clearly decreased. In contrast to various research cases regarding the polymerization time and bond strength of the xenon plasma arc curing light, not enough research exists on the LED curing light, including the appropriate polymerization time. The objective of this research was to compare the bond strength of the plasma curing light and the LED curing light in regards to the polymerization time. The polymerization time needed to achieve an appropriate adhesion strength of the bracket has also been studied. After applying orthodontic brackets using composite resin onto 120 human premolars, the plasma arc curing light and the LED curing light were used for polymerization for 4, 6, and 8 seconds accordingly. This research proved that the LED curing light provided appropriate bond strength for mounting orthodontic brackets even with short seconds of polymerization. The expensive cost and large size of the device limits the use of the plasma arc curing light, whereas the low cost and easy handling of the LED curing light may lead to greater use in orthodontics.

A Case of Cedecea davisae Peritonitis in a Liver Cirrhosis Patient / 감염

Cedecea davisae is a motile, Gram-negative rod in the family Enterobacteriaceae which is positive for lipase, DNase and catalase, and negative for gelatinase and oxidase. This bacterium is rarely isolated in the clinical specimens. We isolated C. davisae from the ascitic fluid of a 49-year old male patient with liver cirrhosis who was diagnosed as acute bacterial peritonitis. Bacterial identification was performed by API 20E and VITEK. Antimicrobial susceptibility test showed that the isolate was susceptible to cefotaxime, piperacillin, and imipenem. Peritonitis of this patient was improved by imipenem therapy. This is the first reported case of peritonitis caused by this organism.

Usefulness of Echocardiography in the Evaluation of Paracardiac Masses

BACKGROUND: Echocardiography gives a window to mediastinal or paracardiac structures. When mediastinal or paracardiac masses are detected by a routine chest X-ray and thoracic CT, the difference between vascular and nonvascular lesions may be difficult to diagnose. In these situations, echocardiography has been successfully used recently. CT can be easily standardized and allows visualization of the whole chest, but it is less precise in defining highly mobile structures, more expensive and difficult to perform in patients with orthopnea. But echocardiography is easy to perform, gives real time images. We performed this study to evaluate the usefulness of echocardiography in the identification and investigation of the structural and functional effects of paracardiac masses. METHODS: Twenty patients with paracardiac masses detected by chest X-ray and thoracic CT were examined by transthoracic and/or transesophageal echocardiography. We studied the characteristics of masses and compression site by 2-D echocardiographic techniques and also evaluation of functional effects of a paracardiac masses on heart and great vessels by color pulsed waved Doppler echocardiographic techniques. RESULTS: Nine patients(45.0%) had cystic masses, eleven patients(55.0%) had solid masses. All cystic masses revealed benign, and all solid masses revealed malignant. Among metastatic paracardiac tumors, the most frequent primary site were lung. heart chambers were compressed by paracardiac masses in five cases(26.7%) and great vessel compressed in thirteen cases(76.4%). Turbulent flow and peak velocity documented by color and PW dopple suggested that it is hemodynamically significant compression states of the great vessels by masses. CONCLUSIONS: We consider that echocardiography is as useful as other noninvasive radiographic techniques in the evaluation of paracardiac masses and their mechanical effect upon the function of the heart and great vessels.