The effectiveness of plaque disclosure by several liquid food colourants and disclosing agents was compared in a group of eight subjects. The subjects refrained from all forms of oral hygiene for a 48-hour period prior to rinsing with 5 ml of each dye in turn at weekly intervals. Kodachrome film records were taken and projected for the assessment of plaque staining efficacy by a panel of 38 assessors. Acceptability with respect to taste, extent and duration of mucosal staining and any side effects was also evaluated.
The food colourants were as effective as the disclosing agents. Ability to stain plaque appears to be related not only to the constituents of each dye, but also to their concentrations and relative proportions. Other desirable properties of an ideal disclosing agent tended to be fulfilled to a level equivalent to, or better than, that reached by the proprietary disclosing agents. Difficulty in obtaining proprietary disclosing agents should not act as a handicap to achieving better levels of oral cleanliness as inexpensive food colourants of equal effectiveness to the best proprietary agent are readily available.
