The possibility of measuring plaque growth in vivo within 24 hours.

Abstract

The utility of a planimetric method for measuring in vivo plaque growth on teeth within 24 hours was tested. A reproducible photographic technique was developed. With this technique color slides were made after plaque disclosure with neutral red 0.5% and enlarged up to 25 times natural size for tracing on paper. The percentage of tooth surface covered by plaque was calculated with a planimeter. To obtain a stable and interpretable staining of the plaque three dye applications were applied. The interpretation of the slides was only reproducible when the slides were examined the same day and with the use of a tooth outline. Under these conditions an intra‐examiner correlation coefficient of 0.999 was found. Furthermore, it was possible to detect significant differences in rate of plaque growth between two subjects within a time interval of four hours.