title: Adequte cohort sizes for caries clinical trials.
abstract: Methods of determining cohort sizes were examined to determine their appropriateness for use in multi-group caries clinical trials. The appropriate method to sue depends on the type of trial being planned. It is shown that multiple comparison methods using certain Bonferonni type t-statistics ought to be used in trials in which different levels of frequencies of application of known caries inhibitors are being tested. It is also demonstrated that using the F-test procedure in the determination of cohort sizes can result in unacceptable low sensitivity levels being realized for the comparisons of primary concern. Tables are presented which can be used to determine group sizes needed to achieve specified sensitivity levels for two-groups trials and multi-group trials.
mesh_terms: D002986:Clinical Trials as Topic; D004245:DMF Index; D003731:Dental Caries / Q000517:prevention & control*; D006801:Humans; D008722:Methods; D011446:Prospective Studies