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 promot e the passage of bacteria; thus, recontamination of sound dentin and/o r the pulp canal space is feasible. The aim of this study was to deter mine the marginal microleakage between two different amalgams (Tytin a nd Valiant PhD-XT), three different composites (Tetric, Charisma, and Polofil Molar), and one glass-ionomer cement(Ketac Silver) and gold ca st crowns using a helium gas microleakage method. In order to standard ize the research parameters, gold washers with standardized dimensions were used as study models together with a helium leakage testing devi ce, Standardized cavities were punched into the gold washers, The cavi ties were filled according to the manufacturers' recommendations with the different materials. The amount of helium passing the marginal int erface between the fillings and cavities was measured with a mass spec trometer 48 hours after the fillings were placed and after 100, 1000, and 2000 thermocycles (5 degrees C-55 degrees C). The results showed t hat amalgam allowed the least microleakage. Ketac Silver showed the gr eatest 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 signi ficant ascending tendency when compared to the composites and amalgams after 100, 1000, and 2000 thermocycles.