What is NOT a characteristic of root canal filling materials?

Root canal filling materials are designed with several important characteristics that contribute to their effectiveness in endodontic treatments. One such characteristic is that they should ideally provide a tight seal within the root canal system to prevent reinfection, and part of achieving that is having a suitable setting time.

The option stating that root canal filling materials should be quick in setting is not typically a characteristic that is prioritized. This is because a quick setting material might not allow enough working time for dentists to ensure proper filling and adaptation within the canal system. Instead, materials used in root canal procedures are often designed to have a setting time that allows for careful placement, manipulation, and ensuring a proper seal.

In contrast, a tacky adhesive property is valuable as it helps the filling material adhere to the canal walls, preventing leakage. Being radio opaque is important because it allows the material to be visible on radiographs, aiding in diagnosis and evaluation of the treatment. Lastly, materials that are non-irritating to periapical tissues are essential to minimize discomfort and promote healing following the procedure.

Thus, while being quick-setting might appear advantageous, it does not align with the ideal characteristics expected from root canal filling materials, making it the correct response to the question.