A Practical and Systematic Review of Weibull Statistics for Reporting Strengths of Dental Materials
Janet Quinn, George D. Quinn
Objective: To review the history, theory and current applications of Weibull analysis sufficient to make informed decisions regarding practical use of the analysis in dental material strength testing. Data: References are made to examples in the engeering and dental literature, but this report also includes illustrative analysis with fractographic examination and Weibull plots and parameters obtained for a dense alumina and two feldspathic porcelains. Sources: Informational sources include Weibull's original articles, later articles specific to applicaitons and theoretical foundations of Weibull analysis, texts on statistics and fracture mechanics and the international standards literature. Study Selection: The chosen Weibull analysis are used to illustrate technique, the importance of flaw size distributions, phyiscal meaning of Weibull parameters and concepts of "equivalent volumes" to compare measured strengths obtained from different test configurations. Conclusions: Weibull analysis has a strong theoretical basis and can be of particular value in dental applicaions, primarily because of test specimen size limitations and the use of different test configurations. Also endemic to dental materials, however, is increased difficulty in satisfying application requirements, such as confirming fracture origin type and diligence in obtaining quality strength data.