Why children can't use electric tooth brush for adults? What will happen if they use adult machine with small head. Does it irritate developing follicle

Why not?? . Depends upon the age of the child. Until age 8 or 9, they lack the dexterity to safely and effectively clean their own teeth--so we must rely on the parents. Unfortunately, oftentimes, they aren't all that helpful either! I have used floss followed by a sonicare to clean my son's teeth every night since he was 3 years old--before that we did it manually. He has no dental issues related to disease.