Improved Zinc Oxide-Eugenol Type Cements

¹ Dental Research Section, National Bureau of Standards, Washington, D.C.

Incorporation of rosin, hydrogenated rosin, fused quartz, and/or metallic oxides such as mercury or lead oxide into the zinc oxide powder of zinc oxide-o-ethoxybenzoic acid (EBA)-eugenol mixes greatly reduced the water solubility and disintegration of otherwise suitable cements. Cements having higher powder-liquid ratios, rapid setting times, and improved compressive strength were obtained. The most desirable compositions employed powder-liquid ratios of 2.80-3.70 gm. per 0.4 ml. of liquid and hardened within a few minutes, to give cements having negligible solubility and disintegration and crushing strength ranging from 8,000 to 11,700 psi. Subject to clinical evaluation, these cements should prove useful in many dental applications. Mixtures of 2-propoxy-5-methylbenzoic acid (PMBA) and zinc oxide harden without accelerators. The resulting cements show unexpectedly high water solubility that would limit any possible clinical applications.