Relationship of Eugenolate Formation to the Setting Mechanism of Zinc Oxide Eugenol Cements

Abstract

In Dentistry, a mixture of eugenol liquid (extract of oil of cloves) and zinc oxide powder enjoys many favored uses. The mixture is used as an obtunding temporary filling material, for temporarily cement­ ing dental inlays, crowns and bridges, for endodontic treatment and for taking impressions of edentulous cases. Despite this popularity of the material and its significance in dentistry, the hardening or setting mechanism of the material is not full y understood. Review of the literature 1 • 6 indicates that the major problem with respect to the setting of zinc oxide­ eugenol (ZOE) cement is whether zinc cugenolate crystals form as a result of the setting reaction and whether their formation causes the setting of the mix. The studies that dealt with the acceleration of ZOE 7 • 11 showed no systematic work to study the ef­ fect of an accelerator on the setting time of ZOE. The accelerator's efficiency was referred to its cation by some investigators 11 and to its anion3 by others. The purpose of this investigation was to study the effect of several accelerators when used in a powder form and as eugenol solutions on the setting time of ZOE; to study the relationship between the time of formation of eugenolate crystals and the setting time of ZOE; to illustrate whether the acceleration of ZOE is cationic or anionic in nature; and to study the effect of accelerator concentration 12 and eugenolate con­ centration on the compressive strength of ZOE.