It's a daily battle to get our seven-year-old to brush his teeth. Any recommendations? A Guest Expert Judith Tanenbaum, DMD, replies: The basics are: demonstrate and explain, over and over and over. Tell your child that just as he has to wash his hands to get the dirt off, so he has to brush his teeth to get off the special dirt that accumulates there. Show your child the white creamy substance that appears on his teeth when they are not properly brushed and explain that this substance, called plaque, is full of germs. But unlike dirty hands, which actually look clean after they are washed, plaque is a white substance found on white teeth, so it doesn't show up very well.