Bacterial microleakage of Cavit, IRM, and TERM.

In this in vitro study, a model system was developed and tested to evaluate the sealing ability of temporary restorative materials used in endodontic access preparations. The materials studied, Cavit, IRM, and TERM, were tested on 40 premolars against a known bacterial species, Streptococcus sanguis. The leakage of bacterial cells was checked 4 and 8 days after initial immersion in the culture. Thermocycling was introduced on the fourth day. After 8 days the cement thicknesses were measured after the teeth had been longitudinally sectioned. Before and after thermocycling, IRM was less leakproof than Cavit (p < 0.05) and TERM (p < 0.05). Thermocycling aggravated percolation in the case of IRM, and decreased the tightness of Cavit, whereas TERM remained leakproof. The thicknesses were as follows: Cavit, 3.73 mm; IRM, 3.45 mm; and TERM, 5.49 mm. There was no statistically significant relationship between thickness and tightness.