OR04 - The Effect of Dentin Tubule Moisture on the Setting of Bioceramic Sealer

The purpose of this study was to assess the setting ability of EndoSequence BC sealer (Brasseler) in two different moisture environments to demonstrate whether moisture contained within the dentin tubules is sufficient to allow setting. Single-rooted extracted human teeth (n=20) were decoronated, endodontically prepared, obturated with BC Sealer, and sealed apically and coronally with glass ionomer. For 10 specimens, no coating was placed on the root surface and they were immersed in PBS within individual containers (PBS-NotCoated). For the other 10 specimens, two coats of acrylic nail polish were applied to the root surface to provide an external seal of the radicular dentinal tubules and placed into dry containers (Dry-Coated). All specimens were stored at 37°C for seven days. Following storage, roots were sectioned 5 mm from the apex, sealer set was evaluated, and followed by Vickers microhardness testing of sealer on the coronal section surface. Based on an independent T-test, there was a significant effect (p < 0.05) of storage condition on microhardness. For the PBS-NonCoated teeth, set sealer mean(SD) microhardness values (MPa) were 41.97(12.45). In contrast, the Dry-Coated specimens did not set completely and hardness testing was not possible. For the sealer set evaluation, a semi-solid/crumbly or soft/mushy set was respectively observed in 40% and 60% of the Dry-Coated specimens, while in 100% of the PBS-NotCoated group the sealer set solid/hard. Within this study storage condition moisture had a significant effect on the setting of BC Sealer, suggesting dentin tubule moisture alone is insufficient for setting.