Here is my understanding of fluoride....
The pro of fluoride is that it helps to harden the surface of the tooth. When teeth first emerge they are in a more delicate state. The enamel is not complete. So the baby teeth newly emerged are vulnerable.
The main con in my mind is its toxcicity. Though in small amounts many claim that this does not matter. Here is a link http://www.shirleys-wellness-cafe.com/fluoride.htm
In fact too much fluoride can cause teeth to become brittle. I remember as a young child having big white spots on my teeth which is a sign of fluorosis.
On a deeper level I feel that are society has become very externally based. People from societies that do not eat the refined, packaged fast foods that we eat have beautiful teeth because they ate a mineral rich diet. On the other hand the western cultures have not done this so from generation to generation that eats poorly we pass on these traits. We tend to do things from the outside. I just heard of how seals are being recommended. This to me is a false assurance that does not realize that the state of the teeth is an reflection of the health inside the body.
In my research , and in school I have learned that fluoridated water is unhealthy as is injesting fluoride. The only way that sounds even effective and not as toxic is wiping a small amount of fluoride on the teeth and wipe off. It can cause nausea if injested. Though if your child does not have cavities it would probably be even better to not feed them sticky dried fruits which stick between teeth and crevices, orange juice which is acidic on teeth(even though it is wonderful and alkaline in the body) It is pretty acidic for emerging teeth especially when they do not want to brush afterwards...), and eat a mineral rich diet. If you are still nursing you can drink horsetail, nettle tea, etc.....my son loves this as well...eat sea weeds, carrot juice is high in calcium....teeth need calcium, phosphorous, vit d(regular sunlight, spirulina).....then you are healing from the inside out. then you are making strong teeth and at the same time not exposing the new teeth to things that will weaken them.
Again these are just my ideas I am an herbalist and have recently looked into this for my sons teeth. Water should be fine. There is also a product called xylitol gel that some use (health food store).This is a naturally occuring sugar that bacteria will not eat.good luck!