@donovan all the studies for HPA seem to be on incipient decay, not progressed decay with destroyed enamel and tooth structure, so there’s no clear research I’ve found on the structure being re-formed through the introduction of enamel-like components. Possible that scientists just assume it isn’t possible so they haven’t studied it, although it seems plausible that if you can restrengthen existing enamel with calcium and phosphorus those same minerals will reform the structure itself.
L