A suggested method for mixing direct filling restorative gallium alloy.

Good wettability is one of the desirable physical properties of mercury-free gallium-based alloys (Gallium Alloy GF). However, wettability, while providing good adhesion to the cavity wall, has the adverse effect of causing stickiness to the inside of the capsule during mixing, and also to the metal hand instruments used for packing. To control this stickiness the alloy mixture was treated with a small amount of alcohol using two different methods. In both groups (alcohol-added and alcohol-treated groups), 5, 10, or 15 microliters of alcohol was added. However, for the alcohol-treated group, the alcohol was shaken from the mixture. In both groups, remarkable improvement was seen in their handling properties, for the alloy mixture did not adhere to the inside of the capsule and was easily taken out as one mass. Compressive strength, tensile strength, and creep were tested in the alcohol-added/-treated groups, and compared with those of a control (conventionally mixed gallium alloy) and a high-copper amalgam (Spherical-D). All tests were done according to ISO 1559 (International Organization for Standardization, 1986), and the results were analyzed using one-way ANOVA (Duncan, P < 0.05). Surface microhardness (KHN) and dimensional change during hardening were evaluated according to ISO 1559 and compared to the control results. In mixing Gallium Alloy GF, an addition of less than 5 microliters of alcohol had the effect of preventing the alloy mixture from sticking to the inside of the capsule and remarkably enhanced the handling properties. This suggested mixing technique did not alter either the mechanical properties tested for this material or the desirable dimensional expansion that occurs during hardening.