The placement of a wet cotton pellet against Mineral Trioxide Aggregate (MTA) is often recommended to ensure the completion of its setting reaction. But a recent study states, presence of moisture in the surrounding environment of the restoration is sufficient for the setting process.
This study by The Open Dentistry Journal aimed to evaluate the setting behavior of MTA Angelus and NeoMTA by comparing their hardness after placing them in dry and moist conditions.
A simulated open apex was created on 40 polyvinyl tubes. The apical 4 mm of the tubes was filled with the two materials, NeoMTA Plus and MTA Angelus. Both groups were subdivided into two subgroups based on the dry and wet conditions. A wet cotton pellet was placed above the two materials in the wet group, and the coronal segment was sealed using Type II Glass ionomer cement.
Gutta-percha was placed against the test materials in the dry group with the coronal segment sealed with amalgam. Samples were placed in an oasis soaked in phosphate-buffered saline for seven days in 100% humidity and at 37°C. Microhardness was measured independently at 4 and 2 mm from the apex.
The presence of dry or wet conditions had no significant effect on material hardness. MTA Angelus showed significantly higher hardness values compared with NeoMTA Plus.
Conclusively, the moisture of the periapical environment can compensate for the absence of a wet cotton pellet and is adequate for the setting of the materials.