DMG America, a dental technology company out of Englewood, N.J., is selling a light cured infiltrant resin that is useful for treating early cavities. At the very early stage of tooth decay, before a formal, treatable cavity has developed, fluoride treatment is often used as prophylaxis. But after a certain level of tooth decay, fluoride will be of no use, yet drilling the tooth to treat the cavity is not merited either, since filling a cavity with this method destroys healthy tooth