Clinical Studies of Dental Cements: IV. A Preliminary Study of a Zinc Oxide-Eugenol Cement for Final Cementation

An experimental reinforced zinc oxide-eugenol cement of compressive strength 8,000 to 9,200 psi (562 to 647 kg/sq cm) was studied clinically for the final cementa-tion of all types of inlays, crowns, and bridges. Patients were recalled and their teeth were examined for loose restorations and symptoms of leakage. Success rates of 94.4 % for single restorations and 93.6% for bridge retainers justify further clinical use of the cement. The problems associated with the cementa-tion of dental restorations with zinc phos-phate cement were outlined in a previous paper. ' A means of alleviating these prob-lems by the interim cementation of restora-tions with a zinc oxide-eugenol cement was discussed. Because these cements must allow subsequent removal of the restora-tion before final cementation with a zinc phosphate cement, there is the ever-present danger of a restoration becoming loose and leaking without the patient's knowl-edge, a situation which is usually accom-panied by rapid caries of the abutment tooth. Numerous attempts have been made in recent years to produce a fortified zinc oxide-eugenol cement that would be strong enough for use as a final cement, and elim-inate the period of interim cementation. Although zinc oxide-eugenol cements have been produced with a compressive strength as high as 10,000 psi2 (703 kg/ sq cm), this is still below the 12,000 psi (844 kg / sq cm) minimum set by the ADA specification.3 Horn4 reported a clinical study of a zinc oxide-eugenol cement of compressive strength of 10,000 psi (844 kg/ sq cm) used over a two-year period in This investigation was supported by a General Re