Compression Fracture Resistance of Four Different Glass-ionomer Cements

Objectives: Aim of the study was to compare fracture resistance to compression of four different GIC materials filled in Class II type cavities.
Methods: For the study purposes, zirconia ceramics class II cavity models were prepared according to standard preparation. Each tested group comprised 6 samples (models). In order to prepare restorations models were filled with four different materials: Equia Forte (GC), Equia Forte HT (GC), Ketac molar (3M Espe) and Ionostar Molar (Voco). Materials were applied according to manufacturers instructions and with aid of sectional (anatomical) matrix. Models were stored at 37 C (100% humidity) for 24h prior testing. Each specimen was tested using an Universal testing machine (LRX, Lloyd Instruments) at 1 mm/min crosshead speed and loaded to fracture using compression rod (diameter 1,5mm), with 1kN load cell. Statistical analysis of data was performed by one-way analysis of variance (ANOVA) and Tukey HSD post hoc test.
Results: Equia Forte and Equia Forte HT showed significantly better fracture resistance comparing to all other materials (Equia Forte 257,2N; Equia Forte HT 245,3N; Ketac Molar 140,7N; Ionostar Molar 114,5N). Type of the fracture was cohesive in all cases. Most Equia cavity models (samples filled with Equia Forte and Equia) fractured together with the restorations (73%).
Conclusions: Equia Forte and Equia F HT performed similarly and significantly better than the other materials tested. Fracture resistance to compression of materials filled in Class II type ceramic cavities could be valuable testing procedure for GIC testing.