A practical and systematic review of Weibull statistics for reporting strengths of dental materials.
OBJECTIVE
To review the history, theory and current applications of Weibull analyses sufficient to make informed decisions regarding practical use of the analysis in dental material strength testing.


METHODS
References are made to examples in the engineering and dental literature, but this paper also includes illustrative analyses of Weibull plots, fractographic interpretations, and Weibull distribution parameters obtained for a dense alumina, two feldspathic porcelains, and a zirconia.


METHODS
Informational sources include Weibull's original articles, later articles specific to applications and theoretical foundations of Weibull analysis, texts on statistics and fracture mechanics and the international standards literature.


METHODS
The chosen Weibull analyses are used to illustrate technique, the importance of flaw size distributions, physical 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 applications, 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.
Quinn
Janet B
JB
ADAF Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, MD, USA.
Quinn
George D
GD
D003764:Dental Materials; D003799:Dental Stress Analysis / Q000379:methods*; D019544:Equipment Failure Analysis / Q000379:methods*; D008422:Materials Testing / Q000379:methods*; D015233:Models, Statistical; D016016:Proportional Hazards Models; D012044:Regression Analysis; D016019:Survival Analysis
D003764:Dental Materials