Effect on the Color Stability of Stained Porcelain due to Tooth Brushing / 대한치과보철학회지

This study is going to compare the degree of color change which occurs in the following two cases of the factors which cause the color change of extra-staining,one is during glazing by the dental technician,the other is tooth brush abrasion which makes the biggest influence on color change. To compare the degree of color change before and after glazing,a sample was made with vintage incisal porcelain No.59 OPAL(Shofu Inc,Japan),after that it was painted with three colors of porcelain stainers,then the degree of color was measured with a spectrophometer(Model Chromaview 300,Spectoron Tech Co.Korea)after it had been treated with firing only and glazing after firing. 40,000-cycle and 80,000-cycle of tooth brush abrasion test were carried out in order to simulate the brushing effect of 4 years and 8 years by using the abrasion tester.The colors were mesured before the test,and after the 40,000-cycle and 80,000-cycle operations and the surfaces were examined by SEM. The results of this study were as follows ; 1.The color change before and after glazing was not great enough to have a clinical significance but the orange color was changed more significantly statistically than the blue and light brown(P<0.05). 2.In the case of the color change of stained porcelain by tooth brushing,carrying out staining and glazing with two-times firings resulted in statically less color change than one firing only(P<0.05). 3.In the case of the difference in the stainer's color,the orange color which has higher chroma was statically more sensitive than the blue color(P<0.05). 4.In the case of the color change after the 80,000-cycle abrasion,all showed color change when there was one firing and the orange stainer showed some color change with clinical significance when firings were done two times.

Endoscopic Mucosal Resection (EMR) as a Curative Treatment of Early Gastric Cancer / 대한소화기내시경학회지

The endoscopic mucosal resection(EMR) is proposed by some Japanese investigators as a curative therapy of early gastric cancer(EGC) because of its minimal invasiveness and excellent results. To evaluate the possible role of EMR as a curative treatment modality of EGC, we retrospectively analyzed l9 casea with EGC initially treated by EMR in Seoul National University Hospital from December 1993 and January 1996. 1) The histologic diagnosis prior to EMR was adenocarcinoma in 12 cases(63%) and adenomatous polyp in 7 cases(38%), which were confirmed as adenocarcinoma after EMR. 2) The histologic curative resection was done in 7 cases(37%). Two cases of them showed recurrence of the gastric cancer and were treated by radical surgery. The other five cases have been closely observed by regular endoscopic examination without recurrence for the maximal period of 1~3 months. 3) Histoiogically inadequate resection(positive cancer cell in resection margin, submucosal cancer infiltration, or no cancer tissue in resected specimen) was done in 12 cases(73%). But two surgically resected cimens of them have no residual cancer cells, and there was no cancer cells in the follow-up biopsy of the other two patients. There 4 cases were seemed to he examples of buring effect of EMR 4) After excluding five depressed lesions greater than 1 cm is long diameter, nine lesions were curatively treated by EMR. So successful EMR rate for strictly indicated lesions wsa 64% 5) There was no signifieant complication related to the procedure. We thnnk that endoscopic mucosal resection has a potential role as a curative treatment modality in a highly selected patient with darly gastric cancer