• The Korean Journal of Applied Statistics
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• v.17 no.2
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• pp.253-267
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• 2004

In some clinical trials, one may see that a significant fraction of patients are cured and their original disease does not recur even after termination of treatment and pro-longed follow-up. This situation occurs frequently in pediatric cancer trials where there are excellent therapeutic results. In such cases, interest concentrated on the difference of cure rates rather than other types of differences in failure distributions. Various authors have investigated the parametric and nonparametric methods for testing the difference of cure rates. In this study, we compare by simulation the power and size of a parametric test and five nonparametric tests in a various range of the alternatives, censoring rates and cure rates. Our objectives are to determine if any test was preferable on the basis of size and power in various situation, and to investigate the effect of the model misspecification.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.341-353
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• 2016

Purpose: The most important factor in longevity studies of dental prostheses is objective and consistent evaluation of the prosthesis. The Korean Academy of Prosthodontics suggested developing a standardized method for longevity studies of dental prostheses. The purpose of this study is to evaluate previously-used criteria and to develop new criteria, in the form of a procedure flowchart and an evaluation sheet. These new criteria may be able to provide a unified standard for future longevity studies of dental prostheses. Materials and methods: A literature review was performed about the evaluation of dental prostheses. Taking into account the strengths and weaknesses of previously used criteria, a novel, intuitive and objective method was developed for assessment of dental prostheses. Then, a pilot survey was performed with the newly developed flowchart and evaluation sheet to determine problems and implement possible improvements. Results: Thirty cases of fixed dental prosthesis (FDP), 25 cases of removable dental prosthesis (RDP), and 13 cases of implant supported prosthesis (ISP) were evaluated. The average life expectancy estimate was 12.82 years for FDP, 5.96 years for RDP, and 4.82 years for ISP with Kaplan-Meier survival analysis. Additionally, possible improvements discovered by the pilot survey were reflected in the flowchart and evaluation sheet. Conclusion: The newly developed KAP criteria, flowchart and evaluation sheet enabled objective and consistent results in trial longevity studies of dental prostheses. It is expected that future studies will not only use the KAP criteria but also further improvement will be made on them.