Diametral Tensile Strength And Microhardness Of Two Different Amalgams

Objectives: To compare the diametral tensile strength (DTS) and microhardness of two admixed amalgams and experimental silver amalgam. Methods: Twenty specimens for each group; GS80 amalgam (SDI, Australia), Dispersalloy amalgam (Dentsply, USA) and experimental silver amalgam were triturated and prepared according to their requirements using high speed amalgamator (Ultramat 2, SDI, Australia). Cylindrical specimens of 4 mm in diameter; 8mm and 4mm in height were prepared under hydraulic press (14 MPa) for DTS and microhardness testing respectively. The specimens were stored in distilled water at 37 oC for 24 hour. The DTS was determine using the universal testing machine (Shidmadzu, Japan) at a crosshead speed of 0.5 mm/min. The microhardness was measured using an automatic Vickers microhardness machine (Shidmadzu, Japan). Data were then analysed using one-way ANOVA and post-hoc tests. Results: For DTS, the experimental silver amalgam (72.71 MPa ± 10.23) was significantly higher compared to GS80 amalgam (39.32 MPa ± 7.79) and Dispersalloy amalgam (41.66 MPa ± 7.78). However, there was no significant difference between GS80 amalgam and Dispersalloy amalgam. For microhardness, there were significant difference among three amalgams; experimental silver amalgam (103.15 VHN ± 4.39) was lower compared to GS80 amalgam (233.82 VHN ± 15.68) and Dispersalloy amalgam (175.38 VHN ± 8.02). Conclusions: The experimental silver amalgam showed the highest DTS compared to other amalgams. However, the reversed values were found for Vickers microhardness number.