Abstract
The purpose of this study was to discover t h e effectiveness of toothbrushing as instructed to children and to discover how long this effectiveness was maintained.
The subjects were 21 children aged 4 to 5 years, attending the nursery school attached to Tohoku University. They had relatively healthy deciduous dentitions.
The experiment was performed as follows.
The plaque on the surfaces of all f u lly erupted teeth was evaluated according to the PHP-Modified and O. P. I. (Occlusal Plaque Index) before giving toothbrushing instructions. Next, the subjects brushed their teeth the way in which they were accustomed. After that the plaque was reevaluated.
They were then given instruction in the horizontal scrubbing technique once a week for three weeks. The p l aque on each tooth was evaluated a week after the last brushing instruction (designated as "right after instruction") and then again after three months and finally six months after instruction.
The plaque scores before and after brushing instruction were given were compared. The results were as follows.
