In short, whatever age-appropriate kind they like! Tooth brushing shouldn’t be an unpleasant chore. If your kids have a flavor or a variety they like, it makes it easier and more fun for them to brush. Pick one that is recommended by the American Dental Association for children’s use. Kids should avoid using adult toothpastes or toothpastes that contain fluoride until they are able to rinse and spit in the sink (age 5-6 typically). Use only a pea-sized amount of paste on the toothbrush, have them attempt it first on their own, but make sure you follow up and help them finish the job well.