Background and objective: Besides hand-mixed formulations, glass-ionomer restorative materials are also available in sealed capsules. The main advantage of capsulated materials is that clinicians cannot alter the powder/liquid ratio. This research was conducted to investigate the consistency of the recommended powder/liquid ratio by the manufacturer in relation to the actual content of the capsule and to determine whether these variations from the manufacturers’ recommendations have any influence on the surface microhardness and compressive strength.

Methods: Two different batch numbers for five glassionomer restorative materials and one Carbomer were evaluated. Twenty specimens were selected from each batch of materials: Chemfil Rock (Dentsply Sirona), Fuji Equa Forte (GC Corp), Glass Fill (GCP dental), Ionofil Molar AC (Voco) and Ketac Universal (3M ESPE) and Riva Self Cure (SDI Limited). The capsules were deconstructed and the powder and liquid were weighed. Additionally, five specimens were prepared for each time interval (days 1, 7 and 180) and the compressive strength assessed. The surface microhardness (Vickers hardness) was completed on five specimens per batch and assessed sequentially at days 1, 7 and 180 on the same specimen after the elapsed time intervals. Results: The results showed that there were significant differences between the two batches for the powder and liquid content for Chemfil Rock (p< 0.001), Ketac Universal (p= 0.029) and Riva Self Cure (p< 0.001). There were no significant differences for surface microhardness or compressive strength between the two batches for any of the assessed time intervals (days 1, 7 and 180).

Conclusion: There were differences between the various batches from the same manufacturer concerning the powder/liquid ratio content. The actual content of powder and liquid from the two batches differed when compared to the manufacturers’ recommended powder/liquid ratio on the package insert for most of the manufacturers. The difference in powder/liquid ratios between batches did not significantly influence the Vickers hardness or the compressive strength for the material over the same time period.