US Patent No. 9,662,276 B2; President and Fellows of Harvard College, Cambridge, MA, have patented a kit for detecting demineralization of a tooth surface. It contains a container comprising an orally acceptable, binding composition comprising iron pyrophosphate (Fe(III)-PP) and a second container comprising an orally acceptable, detector composition comprising gallic acid or an ester thereof that reacts with the Fe(III)-PP to form a visually detectable reaction product. There is also ...