Have your child stand on a step stool in front of the mirror so she can see herself. Give her your toothbrush, while you hold hers. Then, tell her that she gets to brush your teeth, while you brush hers. Stand over her, bending forward with your mouth open, and instruct her to start brushing your teeth. Because she is so busy brushing your teeth, she is pretty much unaware of the thorough job you can do on her teeth. You also get a good view of the backsides of her lower central teeth, where plaque build-up is usually the greatest. Kathleen Traylor, M.D.