Accuracy of the CT guided implant template by using an intraoral scanner according to the edentulous distance / 대한치과보철학회지

PURPOSE: The purpose of this study is to compare the accuracy of the CT guided implant template that was produced by using an intraoral scanner according to the edentulous distance. MATERIALS AND METHODS: Five maxillary casts were fabricated using radiopaque acrylic resin with the second premolars, first molars, and second molars missing. Then a virtual cast was acquired by scanning each resin cast. Implant treatment was planned on the missing sites by superimposing the presurgical CT DICOM file and the virtual cast. Then the implants were placed using a surgical template followed by postsurgical CT scan. The distance and angle of the platform and apex between the presurgical implant and postsurgical implant were measured using the X, Y, and Z axis of the superimposed presurgical CT and postsurgical CT via software followed by statistical analysis using Kruskall-Wallis test and Mann-Whitney test. RESULTS: The implant placement angle error increased towards the second molars but there was no statistically significant difference. The implant placement distance error at the platform and apex also increased towards the second molars and there was a statistically significant error at the second molars. CONCLUSION: Although the placement angle had no statistically significant difference between the presurgical implant and postsurgical implant, the placement distance at the platform and apex showed a larger error and a statistically significant difference at the second molar implant.

Implant prosthesis using intraoral scanner: Case Report / 대한치과보철학회지

Accuracy is the most important thing in implant prosthesis, for this reason it is essential procedure to check the accuracy of impression taking. However, impression material has its own error and the error occurs in model-making procedure. As an alternative way to this, using intraoral scanner can be suggested and many studies were issued reporting that there's no statistically significant difference in accuracy between intraoral scanner and conventional impression. Therefore, the purpose of this study is to report the process of making of implant prosthesis using intraoral scanner, which is more convenient, fast, accurate compared with conventional method.

Using the Lymph Node Metastasis Prediction Program in Curative Resection of Gastric Cancer / 대한암학회지

PURPOSE: The gastric cancer is most frequent malignant disease in Korea. With increase of GNP and social welfare, lot of people pay attention to that. But many of gastric cancer patients who were diagnosed, are advanced -stage III or more- case and produces poor result of treatment. Nowadays many surgeons report that the resection of cancer mass and radical lymph node dissection, which called systematic lymph node dissection, can increase the longterm survival rate and curability of patients. For this purpose Maruyama and his colleagues made a program to predict the 5 year survival rate, cause of death, and the status of lymph node metastases. We put the basic datas of pateints in AGC into Maruyama's program and compare its result to final histologic reports. We would check sesitivity, specificity, positive predictive value, negative predictive values between Maruyamas program and hitologic reports. MATERIALS AND METHODS: From Sep. 1995 to Sep. 1996, We operated 55 patients with gastric cancer with this program in GNUH. We checked the histopathologic reports and put the data into the prediction program. The datas were sex, age, maximal size of tumor, differentiation, gross type and location. We compared status of lymph node metastases, TNM stages between the reports of histopathology and that of predictive program. RESULTS: In early stages the sensitivity and specificity of the program showed poor result but in advanced stages did not. The distribution of lymph node metastasis showed a same pattern. The patterns of perigastric lymph node metastasis were somewhat different according to the location of tumor. But its significance was not confirmed. We analysed the metastaic rate between lymph node groups and compared with the results between two reports. The sensitivity, and negative predictive value were 100% in each groups, and positive predictive value was also high. CONCLUSION: The systematic lymph node dissection is an effective and safe procedure in the surgical treatment of gastric cancer. We suggest that the techniques should be standardized and popularized in Korea. This procedure will improve the survival rate of gastric cancer patients and decrease the local recurrence of gastric cancer.