My dentist was giving me a filling and drilling out all of this decay from my tooth the other day. He told me that he couldn't get all the decay out because it was too deep so he put a layer of fluoride over the decay and then put the filling out over that, but that he might have to go in later and fix it if it keeps on decaying. Does anyone know how likely that the layer of fluoride will stop any further decay? What will the dentist have to do if it keeps on getting deeper? Thanks.