I am a fan of Spiffies Tooth Wipes.  They are basically a "Wet Nap" for teeth.  They come in a box of 24 and are individually wrapped.  Great for travel.  They come in different flavors like Grape and Mango.  After meals or before bed you simply wrap a Spiffie around your finger and clean your child's teeth (or gums).  They are intended for baby and toddler use because they have no fluoride but rather Xylitol - which is a substance that is found naturally in fruit that helps fight bacteria (and bacteria leads to bad breath and cavities).  I bought my Spiffies at Whole Foods Market.  The Spiffies website has a good read about the importance of good oral health http://www.spiffies.com/RightFromTheStart.pdf.