Children using electric toothbrushes showed after 3 years 27 % of healthy-natured dentitions on average ( 46 % of the children had got API-values of up to 30 % ) and the children who used manual toothbrushes showed 22 % of nature-healthy dentitions ( 52 % of the children had got API-values of up to 30 % ) and in 33 % of the control children who received instructions only once a year healthy-natured dentitions were found after 3 years ( 75 % of the children had got API-values of up to 35 % ) .
