Microleakage of gold casting repairs with different materials as quantified by a helium gas system.

Inadequate adaptation of a filling material to a gold crown can promote the passage of bacteria; thus, recontamination of sound dentin and/or the pulp canal space is feasible. The aim of this study was to determine the marginal microleakage between two different amalgams (Tytin and Valiant PHD-XT), three different composites (Tetric, Charisma, and Polofil Molar), and one glass-ionomer cement (Ketac Silver) and gold cast crowns using a helium gas microleakage method. In order to standardize the research parameters, gold washers with standardized dimensions were used as study models together with a helium leakage testing device. Standardized cavities were filled according to the manufacturers' recommendations with the different materials. The amount of helium passing the marginal interface between the fillings and cavities was measured with a mass spectrometer 48 hours after the fillings were placed and 100, 1000, and 2000 thermocycles (5 degrees C-55 degrees C). The results showed that amalgam allowed the least microleakage. Ketac Silver showed the greatest microleakage. Statistically significant differences were found between the composites and both amalgams and Ketac Silver between the 48-hour and 100-thermocycling groups. Yet, Ketac Silver showed a significant ascending tendency when compared to the composites and amalgams after 100, 1000, and 2000 thermocycles.