The Influence of Zinc Oxide Eugenol (ZOE) and Glass Ionomer (GI) Base Materials on the Microhardness of Various Composite and GI Restorative Materials

Roee Itskovich 1, Israel Lewinstein 2, Uri Zilberman 1, 3, *
1 Faculty of Dental Medicine, Hebrew University, Hadassah, Ein Karem, Jerusalem, Israel
2 Department of Oral Rehabilitation, Gabriela Goldshlager School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel
3 Pediatric Dental Department, Barzilai Medical Center, Ashkelon, Israel

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© Itskovich et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Uri Zilberman, DMD, PhD- Pediatric Dental Department, Barzilai Medical Center, 2nd Hahistadrut st, Ashkelon, 78278, Israel; Tel: +972 (0)8 6745854; Fax: +972 (0)8 6745238; E-mail:



Re-examining the well accepted concept that Zinc-Oxide-Eugenol bases (ZOE) have a negative effect on composite restoration materials microhardness, in light of the advancement in composite materials and newer publications.


Five modern composite restoration materials were used, including hybrid (Xtra-fill and Z250), micro-fill hybrid (G-aenial and Gradia-direct) and methacrylate-free restorative material (Silorane- oxirane). Two base materials were used IRM (ZOE-base) and Fuji-IX (GI-base). Samples were made using a designed mold, in which composite discs were cured on top and in close relation to base materials. Micro-hardness testing was performed using a DMH-2 microhardness tester utilizing the Knoop method.


Statistic analysis demonstrated significantly better microhardness of three composite materials when IRM was used as base in comparison to control (G-aenial, Gradia direct and Filtek silorane), and no differences in two materials (Filtek universal Z250 and Voco Xtra-fil). Fuji-IX bases showed a significant positive effect on the microhardness of four composite materials, and a negative effect on one material (Voco Xtra-fill). In comparison with other tested restoration materials, both Voco Xtra-fill and Fuji-IX showed higher microhardness results (P<0.05).


Related to microhardness, both ZOE and GI bases can be used safely as bases under composite restorations. The results of this study together with the results published recently showed that the concept of not using ZOE or GI bases under composite must be reconsidered. Fuji IX showed microhardness results similar to the best composite material and therefore it can be used as a restorative material.

Keywords: Zinc oxide eugenol, Glass-ionomer, Composite, Microhardness, Knoop method, Fuji-IX, IRM.