The pH level of saline solutions was determined 1 hour, 4 hours, 1 day, 2 days, 3 days, and 1 week after roots of human teeth, which had received one of four root canal treatments, were placed in them. The four treatments following instrumentation were filling of canals with laterally condensed gutta-percha and either Sealapex (10), calciobiotic root canal sealer (CRCS) (10), or a Grossman type sealer (10), and filling of only the coronal 2 to 3 mm of canals with Cavit (unfilled, 10). The coronal 2 to 3 mm of all canals in all groups were filled with Cavit. The pH levels of the four solutions were compared to each other and to that of saline solution only. The pH levels of the solutions in the Sealapex group were higher than those of all the other solutions for each of the six times (p less than .01). Although the pH levels of the solutions in the CRCS group were significantly lower than those of the Sealapex group, they were higher than those of the other solutions at 1 hour and at 4 hours (p less than .01). After that there were no significant differences in the level of pH for the CRCS, Grossman, unfilled, or saline-solution-only groups, except that at 3 days and at 1 week the pH levels of the unfilled group were significantly lower than those of all other groups.