Human saliva penetration of root canals obturated with two types of mineral trioxide aggregate cements

The sealing ability of orthograde mineral trioxide aggregate (MTA) root canal filling against human saliva was assessed in vitro. Leakage of gray-colored MTA, white-colored MTA and vertically condensed gutta-percha and sealer were compared. Forty-three extracted single-rooted human teeth were serially instrumented to a file size 40/0.06 at the apex and obturated with either gray-colored MTA (group A), white-colored MTA (group B), or gutta-percha and Kerr Canal Sealer EWT (group C). The teeth were then mounted in a model to test for saliva leakage. After 42 days, one root in group A (9.1%), four roots in group B (36.4%), and nine roots in group C (81.8%) showed saliva leakage. Statistically, a significant difference was found between group A and group C (p < 0.001). No statistical difference was found between group A and group B. Out of the root samples that leaked, the one sample in group A leaked after 36 days. Of the four samples in group B, one sample leaked after 32 days, one sample after 33 days, and two samples after 39 days. All nine samples in group C had leaked after 19 days. It appears that under the conditions of this study both MTA preparations may be more resistant to human saliva leakage than vertically condensed gutta-percha and sealer.