Comparison of Compressive Strength of Glass-Ionomer and Zinc Phosphate Cements

Statement of problem: Insufficient compressive strength of dental cements leads to crack formation and further complications such as unrestrained restorations, secondary caries and pulpal infections. Purpose: The aim of this study was to determine the compressive strength of two kinds of glass ionomer (GI) and zinc phosphate cements (ZPH). Materials and Method: In this study, the compressive strength of two kinds of zinc phosphate cements manufactured by GC (Elite cement 100) and Ariadent company was evaluated. Furthermore, two kinds of glass ionomer cements made by GC (Fuji I) and Ariadent company were examined. Five cylindrical samples were prepared according to ISO 9917 from each cement. After processing the samples in incubator and distilled water for 230.5 hours, they were examined in Instron mechanical tester. The data were analyzed by one way ANOVA and Tukey HSD methods. Results: The compressive strength of GI cements made by GC and Ariadent were 187±40 Mpa and 129±10 Mpa, respectively. Moreover, compressive strengths of ZPH cements made by GC and Ariadent were 83±21 and 123±21 Mpa. According to the results of one way ANOVA, GI cement made by GC had significantly higher compressive strength as compared to other cemens ( p 0.05). Conclusion: Glass ionomer cement manufactured by GC company had a significantly higher compressive strength compared to other cements. However, GI and ZPH cements made by Ariadent were acceptable according to ISO 9917 standards. Key words: Compressive strength, Dental cement, Glass ionomer, Zinc phosphate.