In vitro analysis of techniques that alter the surface hardness of a glass ionomer restorative material

Abstract

Ab s t r A c t Aim: The aim of this in vitro study was to compare the eect of dierent manipulation techniques on the surface hardness of ChemFil Rock glass ionomer.Materials and methods: The changes in Vickers surface hardness ( VH) of ChemFil Rock were evaluated after the application of ve manipulation techniques and compared with one control group (n = 60). The manipulation techniques included: nger pressure set, electronic piezo producing a high frequency set, air piezo producing a low frequency set, heat-set achieved with a curing light and the last technique was a combination of electronic piezo followed by heat-set. Standard set was the control.Results: The average surface hardness for the standard set was 49.5 VH. No statistical dierences were demonstrated when the means were compared for nger pressure set (49.2 VH) or the air piezo set (48.49 VH) with standard set. The electronic piezo (54.21 VH) and the heat-set (57.5 VH) had an increased mean surface hardness when compared to other techniques. Heat-set had the highest surface hardness demonstrating a signicant statistical dierence when compared with standard set, nger pressure set, air piezo set as well as the combination of electronic piezo (p < 0.05).Conclusion: The surface hardness of the glass ionomer cement (GIC) material assessed in this study can be predictably improved by applying the heat-set technique. A command set can be achieved with the electronic piezo or the air piezo, however, the surface hardness will only increase with the use of the electronic piezo.