- Mineral Trioxide Aggregate (MTA) is widely used as a root-end filling material due to several favorable properties.
- Among these, its high pH (approximately 12.5) plays a crucial role in its effectiveness.

- The alkaline environment created by MTA contributes to its antibacterial properties, which help eliminate residual bacteria within the root canal system.
- Additionally, the high pH promotes favorable conditions for hard tissue formation by stimulating cementogenesis and osteogenesis, which are essential for sealing the root-end and facilitating periapical healing.

- While radiopacity is important for visualization during radiographic assessment, it is not the primary characteristic contributing to the biological success of MTA.
- Similarly, MTA has a relatively long setting time rather than a low one, and it is hydrophilic, which actually enhances its ability to set in the moist environment of the root canal rather than hydrophobic.

- In summary, the key characteristic of MTA that significantly enhances its performance as a root-end filling material is its high pH (12.5), which ensures antibacterial action and promotes tissue regeneration.

Reference: Torabinejad, M., & Walton, R. E., *Endodontics: Principles and Practice*, 5th Edition, Chapter 12, Page 320