I have now been a pediatrician for 20 years. During that time, the amount and timing of giving fluoride to children to protect their teeth has changed every couple of years. Pediatricians have a hard time keeping up with the latest recommendations. We realize it can be difficult for parents to keep up to date about fluoride recommendations.
Fluoride is a safe way to prevent "dental caries" or cavities of the teeth. However, too much fluoride can cause "dental enamel fluorosis", which is a spotty discoloration of the teeth that is permanent. Fluoride is in most public water supplies (it is added to help prevent cavities), so many people have tap water at home with a good source of fluoride. Here is a good source of information about whether your wattle supply has added fluoride to protect the teeth. Bottled water that you can purchase has some fluoride in it, but the amount can vary widely. Bottled water also very rarely lists how much fluoride is included. Well water usually does not have fluoride in, but occasionally it does. The water can be tested to determine how much fluoride is in the water. Here is more information from the CDC about fluoride in well water.
We have recommended against using fluoride toothpaste for young children as they could easily swallow too much toothpaste, increasing their risk of the excessive fluoride staining the teeth. The previous recommendation was to wait on fluoride containing toothpaste until the child could spit out the toothpaste after brushing. We found this was often 2 1/2 or 3 years of age. The recommendation now is to use fluoride toothpaste for children as soon as the first tooth erupts (breaks through the gums). But until age 3, use just a "smear" or the size of a grain of rice. After age 3, a pea-sized amount of fluoride toothpaste is recommended.
Our recommendation is to follow the above recommendations: Once your child has their first tooth, start using a grain of rice sized smear of toothpaste with tooth brushing. After the 3rd birthday, use a pea-sized amount of toothpaste. We will keep you updated as the recommendations change!