Handling characteristics of a palladium-free gallium-based alloy compared with a high copper dental amalgam in a simulated clinical trial.

The aim of the current study was to compare the handling characteristics of a palladium-free gallium-based alloys (Galloy®) with those of a high-copper amalgam (Permite C®). The study had a particular interest in the evaluation of the direct placement delivery system used with both alloys. Ten dentists participated in the current study. Each placed two amalgam and two gallium-based alloy restorations in conventional class II cavities prepared in acrylic typodont teeth. None of the participating dentists had used the direct placement delivery system or had any previous experience with gallium-based alloy and no practice was allowed beforehand. The restorations were evaluated according to the following criteria: ease of loading the cavity (delivery system), ease of condensation, capacity to produce and sustain contact area, ease of carving, resistance to damage during removal of the matrix band, overall quality of the restoration and the available working time. Each criterion was given a score on a scale of 1–5 (1: very poor, 2: poor, 3: fair, 4: good, 5: very good). The results showed no statistically significant difference in the evaluated criteria between the two alloys (P > 0˙05) except for criterion number 2 (ease of condensation, P=0˙0005).