Clinical Behavior of o-Ethoxybenzoic Acid-Eugenol-Zinc Oxide Cements

¹ National Bureau of Standards, Washington, D.C.

The possible clinical applications of two formulations containing zinc oxide-hydrogenated rosin powder and o-ethoxybenzoic acid (EBA)-eugenol liquid have been investigated. To evaluate their restorative properties, the EBA cements have been compared with zinc oxide-eugenol cement containing a higher powder-liquid ratio than that commonly employed in clinical work. The materials were used as fillings in posterior and anterior teeth, as sedative restorations, bases, and in pulp-capping.

Incorporation of heat-treated fused quartz into EBA cements improved their carvability and prevented chipping under trimming. The EBA containing fillings wore excessively in the mouth. Although some of the zinc oxide-eugenol cements in the posterior teeth chipped at their margins, all the fillings remained serviceable for the 2-10 months of observation. These clinical findings showed no correlation with laboratory results obtained for solubility, disintegration, and abrasion. Oral effects on the exposed surfaces of the EBA cements should be investigated by microbiological and biochemical methods. To assist such investigations, the chemical mechanism involved in the hardening of the EBA cements should be clarified.

Symptomatic teeth without pulp exposures lost their symptoms and remained vital when restored with EBA cement. On pulp-capping, none of the few teeth studied showed any radiographic changes, and all responded normally to vitality tests during periods of observations from 2-10 months. The cements thus appeared promising as improved sedative bases and as pulp-capping and cementing media.