Flexural and Compressive Strength of new Glass Ionomer Restoratives

Objectives: The aim of this in vitro investigation was to evaluate 3-point flexural strength (FS) and compressive strength (CS) of the new Ketac™ Universal glass ionomer restorative compared to state-of the art and newly launched glass ionomer restorative cements (GIC). In case of FS materials were compared after being stored in water for fixed periods of time.
Methods: Materials used were Equia® Fil (EQF), Equia® Coat (EQC), Equia® Forte Fil (EQFF), Equia® Forte Coat (EQFC), Fuji® IX GP (FIX, all GC Dental), IonoStar Plus (IP, VOCO), Ketac™ Universal (KU) and Ketac™ Universal Aplicap™ (KUA, both 3M ESPE).
FS was tested in accordance with ISO 9917-2:2010 with the proviso that for covering the composition a glass slab was used instead of a foil. Materials were mixed and 2 x 2 x 25 mm³ molds were filled and stored in water at 36°C. After 1h specimens were removed and chamfered. In case of EQF and EQFF EQC or EQFC were applied to one longitudinal surface respectively, brushed-in and light-cured for 10s (Elipar™ S10 Curing Light, 3M ESPE). All specimens were stored in water at 36°C and FS measured after different time periods. A minimum of six specimens were tested for each data set.
CS was tested according to ISO 9917-1:2007 with the proviso that for covering the composition a glass slab was used instead of a foil. Six specimens were tested for each data set.
Data were analyzed by One-Way ANOVA.
Results: The FS and CS values are summarized below. Groups with no statistically significant difference are marked with the same letter (within row).
Conclusions: KU and KUA showed high FS and CS performance. FS values were comparable or significantly superior to FIX and EQF&EQC for all time periods tested. IP, KU and KUA showed significantly higher FS after 24h than EQFF&EQFC even without coating.