OPTIMAL AND PRACTICABLE DESIGNS FOR MEASURING PLAQUE PH-PROFILES

The shape of the plaque pH-profile after consumption of a food item de termines the food's potential caries risk. This and related facts have caused an increased interest in measurements of plaque pH-profiles du ring the last decade. A standard design for these measurements is to t ake equally spaced observations over a certain period of time, The the ory of optimal experimental design gives methods for positioning the m easurements of a pH-profile in an optimized way, The objective is to m inimize the effort given a desired precision of the estimated profile characteristic or to maximize the precision given the number of measur ements, We show that a reduction in the number of measurements up to 5 0 per cent or a respective improvement in precision of the estimates a s compared to standardly applied designs is possible, This implies les s inconvenience for the subjects and better compliance with the needs of investigation, Our study is intended to demonstrate the applicabili ty of the theory of optimal experimental design which has the potentia l to improve the efficiency of medical research.