Compressive strength of three different restorative materials (in vitro study)

Abstract

Objective: This study aimed to compare the compressive strength of zinc-reinforced glass ionomer (ZRGI) restorations with high-viscosity glass ionomer (HVGI) cement and posterior composite restorations. Materials and Methods: Twenty-four cylindrical blocks (6 ± 0.1mm height, 4 ± 0.1mm diameter) were prepared from the three studied materials using a prefabricated Teflon mold and were divided into three equal groups. The compressive strength test was performed by Instron mechanical test system model 1195. Statistical analysis was performed depending on analysis of variance and least significant difference tests at 95% significance level. Results: Posterior composite restoration showed the highest compressive strength (239MPa), whereas there was no difference between ZRGI and HVGI (154MPa and 151MPa, respectively). Conclusions: Although the compressive strength of ZRGI was close to that of HVGI, this fact does not give ZRGI any preference, but it is possible that improvements can be reflected. Other properties can be studied later. We recommend not to rely on ZRGI as permanent restoration instead of posterior composite resin restoration.