In two parallel classes ( 1st class ) of the same elementary school ( Private Martinusschule Mainz-Gonsenheim ) the A-class ( n = 24 children ) was instructed to clean their teeth with a manual toothbrush suitable for children ( Oral-B , Power Tip , Braun AG , Kronberg , Germany ) whereas the B-class ( n = 26 ) received electric toothbrushes ( Oral-B-7 EB 5 K , Braun AG , Kronberg , Germany ) .
