Conditions Affecting the Rehardening of Softened Enamel
WARD PIGMAN 1,
H. CUETO 1,
D. BAUGH 1, and
REIDAR F. SOGNNAES
1 Biochemistry Departments, University of Alabama Medical Center, Birmingham, and the New York Medical College, New York
The best solution developed for rehardening softened enamel surfaces has the following composition: calcium, 1.5 mM/l; phosphate, 0.90 mM/l; fluoride, 0.05 mM/l at pH 7.3-7.4 and 37° C. Extensive rehardening occurred in several hours. Such solutions also "superhardened" intact and ground enamel. Sobel's calcifying solution did not reharden softened enamel unless fluoride ions are present. With fluoride, it rehardened well. Some of the complex relations between pH, supersaturation, and precipitation were described. Studies of other variables may improve the rehardening solutions.
