Teaching oral biology laboratories to large numbers of students by video tape

A two-laboratory video-taped package was developed and presented to 180 dental, dental hygiene, and dental assisting students. The tapes dealt with (1) the growth of plaque in vitro on nichrome wire and on bovine enamel blocks and with (2) the measurement of plaque pH changes in vivo after a sugar solution rinse. The taped presentation was interrupted at frequent intervals to allow the students to perform the procedures. A program describing the use of the phase microscope was also developed and presented. Results showed that all students were able to perform the procedures satisfactorily and complete the laboratory report in approximately 40 percent less time than was required for the conventional laboratory. Students reported that they felt the video tapes had enabled them to master the required material and understand plaque and the food-host-bacterial interaction. Preparation time was at least twice that for the traditional laboratory exercise, and cost-benefit justification will require use of the video tape packages for several years without major revision.