title: Comparative study of Weibull characteristic strength and mean strength of GPCs to confirm the minimum number of samples needed for confident strength reporting.
abstract: This short communication determines the strength of two glass polyalkenoate cements that differ from each other through the composition of their glass phase. Sample sets of n=5, 10, 20 and 30 were formulated and tested in biaxial flexure. The derived mean for each sample set was compared against the Weibull characteristic strength. The mean and corresponding characteristic strength show a maximum percentage difference 10.1%, and the 95% confidence intervals calculated from the mean data encompass the corresponding characteristic strength down to a sample set of n=5. This suggests that, for brittle materials such as glass polyalkenoate cements, it is acceptable to test only five samples of each material in biaxial flexure and the resultant 95% confidence intervals will encompass the corresponding Weibull characteristic strength of the material.
authors.affiliation: Department of Mechanical & Industrial Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3.
authors.forename: Cina
authors.initials: C
authors.lastname: Mehrvar
authors.affiliation: Department of Mechanical & Industrial Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3. Electronic address: curran@ryerson.ca.
authors.forename: Declan J
authors.initials: DJ
authors.lastname: Curran
authors.affiliation: Department of Mechanical & Industrial Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3.
authors.forename: Adel M F
authors.initials: AM
authors.lastname: Alhalawani
authors.affiliation: Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, NS, Canada B3H 4R2.
authors.forename: Daniel
authors.initials: D
authors.lastname: Boyd
authors.affiliation: Department of Mechanical & Industrial Engineering, Ryerson University, Toronto, Ontario, Canada M5B 2K3.
authors.forename: Mark
authors.initials: M
authors.lastname: Towler
mesh_terms: D000704:Analysis of Variance; D016001:Confidence Intervals; D005899:Glass Ionomer Cements; D008422:Materials Testing / Q000379:methods*; D055595:Mechanical Phenomena
chemical_list: D005899:Glass Ionomer Cements
keywords: Biaxial flexure; Fracture; Glass polyalkenoate cements; Mean; SEM; Weibull