Abstract: The specification describes a dry composition and aqueous solution useful in the mineralization of dental plaque. The solution contains 0.01 to 50% W/V of a substance metabolized by bacteria in plaque (urea is exemplified) to raise the pH of said solution, a physiologically acceptable source of calcium ions and a physiologically acceptable source of phosphate ions, both in concentrations to form a stable solution with respect to a calcium phosphate salt, and optionally a fluoride ion generating compound metabolized by bacteria in plaque to release fluoride ions and/or a water soluble fluoride salt, the pH of the solution being from 1 to 9, and the pH and calcium and phosphate ion concentrations being such that the solution remains stable and with respect to the calcium phosphate salt until the substance is metabolized by bacteria in plaque. Results of some dental trials are presented.