Retentive and compressive strengths of modified zinc oxide–eugenol cements

Objectives: This investigation sought to improve the handling and physical properties of a commonly used temporary zinc oxide–eugenol cement by changing the base/accelerator (B/A) ratio or combining it with a petroleum jelly or fluoride varnish. Methods: Twelve modifications of a temporary cement were evaluated in terms of retentive strength, compressive strength at 24 h, film thickness and by scanning electron microscopy. Results: Decreasing the B/A mixing ratio increased the retentive and compressive strengths, but reduced the film thickness of the cement. By increasing the percentage of incorporated petroleum jelly or fluoride varnish in the cement, there was a progressive decrease in the retentive and compressive strengths and in film thickness. Conclusions: Modifications of a zinc oxide–eugenol temporary cement to change the B/A ratio or to incorporate additives resulted in variations in physical properties. All modified forms of the cement had a film thickness less than 25 μm and a compressive strength below 35 MPa. With a wide range of retentive strength, modified forms of the zinc oxide–eugenol cement may be found to have diverse clinical applications.