Histologic changes of tooth and periodontal tissues applying to contraction & intrusion force for the maxillary four incisors of dogs / 대한치과교정학회지

The purposes of this study were to investigate the initial tissue changes on the teeth and surrounding tissues under contraction and intrusive force by contraction UTA. A control and experimental dogs, 10-months in age, were studied. Contraction and intrusive force(60gm) were applied at upper four incisors by contraction UTA. Experimental dogs were sacrificed at 2 weeks and 4weeks after force application, respectively. In this study, 2 experimental groups were designed by the duration of force applied(E1, E2). The specimens were taken around the upper first and second incisor in each groups and were prepared for the H-E and MT stain for light microscopic observation. From the results of the study, the following conclusions may be drown. : 1. In control group, the periodontal ligament width was constant from apical third to cervical third of the root and periodontal fiber arrangement was horizontal or oblique in cervical third, oblique in middle third and apical third. In alveolar bond, smooth appearance was shown with osteoblast. 2. In experimental group 1, in proportion to force was concentrated at labial middle third and apical third of root of the upper first and second incisors, root of these tooth tipped labially and intruded at a time. 3. In experimental group 2, periodontal ligament width and arrangement was similar to control and observed strong calcified response at the labial middle third of root. But, alveolar bond resorption and cementum resorption were as before seen at labial middle third and apical third of root force was concentrated.

The Clinical Application and Usefulness of transesophageal Echocardiography

BACKGROUND: During the past few years, transesophageal echocardiography(TEE) became one of most impartant method to detect various cardiac disease. But it was performed less than 10% of transthoracic echocardiography(TTE) in most of echocardiographic laboratoties because of major and minor complicatios associated with this procedure. The purposes of this study are to evaluate the clinical applications and the usefulness of transesophageal echocardiography in various cardiac disorders. METHOD: From 1990 to 1995, 942 cases were included in this study. All subjects were taken TTE and TEE simultaneously The causes of request, related side effect, cause of failed cases, and the benefit of TEE compared to TTE were analysed. The benefit of TEE were classified into major and minor benefit. Major benefit was defined as to diagnose the disease or to change the therapeautic method by TEE. Minor benefit was defined as to have additional findings by TEE whic could not be enrolled in major benefit. RESULTS: 1) The success rate of TEE was 95.5%(900/942). In 42 failed cases(4.5%), 19 were interrupted procedure earlier, 16 were failed to insert the TEE probe, 4 cases showed arrhythmia, and 3 cases had esophageal stricture or varices. 2) The causes of request were to assess the prosthetic valve function(35.5%), cardiac source of embolism(23.7%), valvular heart disease(22.7%), congenital heart disease(10.2), aortic disease(2.7%), endocarditis(2.3%), cardiac mass(1%), and coronary artery disease(1%), in orders. 3) The benefit of TEE was 77%, congenital heart disease was revealed greatest benefit(97%), but major benefit was highest for the evaluation of cardiac source of emboli(100%). CONCLUSION: TEE was very useful method for the detection of intra-cardiac and aortic abnormalities. TEE is a relatively safe procedure but it is a semi-invasive method and has few complications. So it is wise to apply TEE as adjuvant method of TTE.