CONTROL OF A MULTIPLE DENTAL PLAQUE CULTURE SYSTEM AND LONG-TERM, CONTINUOUS, PLAQUE PH MEASUREMENT USING LABVIEW(R)

LabVIEW(R) software on a Macintosh computer was used to control the se parate delivery of nutrients, reagents and gas to an in vitro multiple dental plaque model system and to continuously acquire pH data. The s pecific design aims, achieved using LabVIEW, were: computer control of times for delivery of a simulated oral fluid, sucrose and test reagen ts; continuous pH data acquisition from electrodes placed within the f ive plaques for experimental periods of several weeks; the saving of d ata to disk; a continuous chart display of pH with regular printouts; and data analysis during and after acquisition. A custom-designed sign al conditioner linked pH electrodes to a computer input/output board a nd a switching box linked fluid delivery pumps. Programming with LabVI EW, a graphical programming language which uses icons to represent com mands, functions, inputs and outputs, involved the construction of sof tware modules, 'virtual instruments', which look and function much lik e real laboratory instruments. Separate 'virtual instruments' were wri tten for culture system control and pH data acquisition. Although LabV IEW concepts and procedures required training and considerable practic e, the use of LabVIEW simplified programming and proved a powerful and flexible system for data acquisition and culture control.