Without taking a stand on fluoride, I must advise you that infants do have teeth, they simply have not yet erupted. Children are also given fluoride during their growing years to incorporate fluoride into the enamel of their not yet erupted adult teeth. Adults do not take systemic fluoride supplements for their teeth, as their teeth have already developed and erupted. Topical fluorides are used in adults (and children). It is proven that there is significantly less dental caries disease in children and adults that have had systemic fluoride supplements. Too much fluoride during tooth development will cause dental fluorosis, leaving teeth a mottled and ugly appearance, but caries resistant.
One may expect increased dental bills if you do not give your child fluoride, and dental abcesses can be life threatening. I have seen many of them requiring hospitalization and drainage.