Flexural Strength of Glass Ionomer Treated with Different Curing Methods

Objectives: It has been suggested that heat and ultrasonic curing during setting of glass ionomer cements (GIC) can improve mechanical properties. The aim of this study was to assess the influence of externally applied 'command' set applications on the flexural strength of several GIC specimens. Methods: Ten specimens (2 x 2 x 25mm) of five different restorative GIC (Fuji IX FAST, Fuji VII, Fuji VIII, Megacem, Ketac Molar Easymix) were fabricated and ‘command' set using four different methods: standard curing conditions (SC), ultrasonic excitation (UC), by an external heat source for 20 seconds (HC20; Elipar Highlight, Espe) and for 40 seconds (HC40). The flexural strength of these samples was measured with 3 points bending test. Data were compared using one-way ANOVA and Tukey HSD test. Results: All experiments showed a decrease in strength going from UC to HC, and SC. The flexural strength of Fuji VII and Fuji VIII decreased by UC compared to the SC values. The flexural strength of Megacem was also decreased by UC and HC compared to the SC values. There was no established statistical significant difference between investigated material and techniques. There was no clear relationship between the ultrasonic excitation in the sample and the flexural strength of GICs. Conclusion: Mechanical properties of examined GICs were not significantly affected with heat or ultrasound excitation during curing process.