In the present study, an erythrosine-containing plaque coloration agent manufactured by company X was applied to a total of 40 3rd grade elementary school pupils and the detection of their plaque was attempted by 4 different methods.
In the two methods in which effect of erythrosine was maintained for one minute, the amount of residual erythrosine in the oral cavity was about 40%, whereas in the cases in which its effect was maintained for 20 seconds the residual amount was found to be anywhere from 34 to 37%.
Of the four different methods used, the 4th method in which subjects were instructed to chew the coloration agent 3 times for the purpose of diffusion in the mouth and ejected it after 20 seconds gave a statistically smaller value than the other three methods.
Although the method of 20 seconds was in some cases found to be inferior to that of one minute with respect to the degree of coloration, it was of sufficient value to evaluate the manner of plaque attachment in the elementary school children.
When the time of use of erythrosine was under 20 seconds, the state of plaque coloration was inadequate of the purpose of evaluation and, therefore, it was concluded that the 4th method was the most satisfactory one for the purpose.
The majority of methods to determine the plaque deposition by erythrosine or other agents are thought to have a sufficient degree of safety, but it is necessary that proper attention should be paid to their application, so that the residual amount of chemicals in the oral cavity is reduced to a minimum.