Silicate Cements and Acid Production

¹ Eastman Dental Dispensary, Rochester 3, New York

The simple experiment described shows that the acid produced by silicate cements on leaching is better given qualitative and quantitative value by titration with alkali than by measurements of pH. The acid produced when the leach is a physiologic fluid is larger in quantity than when the leach is distilled water. This difference may well be due to the pH of the surrounding liquid, and it is postulated that the pH referred to usually in relation to cements is that pH at which the solution of the cement ceases.

The surface area of cement exposed to leach and the elapse of time influence the quantity of acid produced. Most acid is produced within 1 hour of mixing. The basic nature of tooth material, the small amount of acid that might be leached beneath a restoration in the mouth, and the other conclusions arrived at in this experiment make it doubtful that acid could be the sole cause of pulpal degenerations beneath unlined silicate restorations.