Doctor Robert recommends:
Before your children is good at rinsing and spitting out the toothpaste, parents should use just a thin smear
amount of toothpaste when brushing their children. Even if you are only using a fluoride-free toothpaste
for your infant, you should still only use a smear amount. This is to prevent the infant getting accustomed to much sods and flavor, preparing for an easier transition to a fluoridated toothpaste
Once you child can reliably rinse and spit out completely, a pea-size
amount of toothpaste should be used.
In this picture, “Regular” is too much even for an adult.