Where I can get toothpaste for my 4 month old? And how do I brush her teeth?

I use Kids Spry Tooth Gel, with Xylitol. It can be used for baby age 3 Months and up, all natural ingredients, safe to swallow and flouride-free. Xylitol has been proven to prevent tooth decay. My kids like the light taste too. It is very important that this tooth gel does not contain Glycerin, which is an ingredient in most toothpaste and gels. Glycerin can interfere with strengthening your teeth, and it layers your tooth in a sticky film that keeps the minerals in your saliva from interacting with your enamel to strengthen it. You can purchase from Iherbs and enjoy free shipping when hits certain amount of order. http://www.iherb.com/Xlear-Inc-Xclear-Kids-Spry-Tooth-Gel-with-Xylitol-Strawberry-Banana-2-0-fl-oz-60-ml/29022 When your baby is older, i.e. more than 2 years old, it is recommended that to use flouride based toothpaste. I recommend this brand from iherbs too http://www.iherb.com/Tom-s-of-Maine-Natural-Children-s-Fluoride-Toothpaste-Silly-Strawberry-4-2-oz-119-g/37147