Microleakage of IRM used to restore endodontic access preparations

The effect on microleakage of varying the powder-to-liquid ratio (P/L) of IRM used to restore endodontic access preparations was evaluated. Crowns of noncarious, nonrestored extracted human teeth were used in this study. Microleakage was measured using a fluid filtration technique prior to access preparation to obtain control measurements. After access preparation, IRM restorations were placed using P/L of 2, 3, 4, 5, and 6 g/ml, using the manufacturer's recommended dispensing scoop and dropper, and using 2 P/L in a new capsulated IRM delivery system (IRM CAPS). Microleakage measurements were made after various time intervals and after thermal stress. The results indicated that the lower P/L provided the best seals. All groups demonstrated significant microleakage measurements after thermal stress. Significantly greater microleakage measurements were obtained with the P/L of 6 g/ml and the manufacturer's recommended dispensing scoop and dropper. A P/L of 2 g/ml demonstrated less microleakage than the other groups tested.