Australian Dental Council (ADC) Practice Test

The ideal extension for a root filling in root canal therapy is to extend to the dento-cemental junction. This is crucial because it helps ensure that the filling material is adequately positioned to prevent the ingress of bacteria and provide an effective seal in the canal system. By extending the root filling to this junction, you support the healing process by minimizing the potential for reinfection.

This location is important because it often corresponds with the anatomical limits of the root canal and the surrounding attachment apparatus. Filling to the dento-cemental junction also helps in immobilizing any functioning periapical tissues, allowing for proper healing.

When considering other options, extending to the apex while avoiding penetration can potentially leave untreated voids, making it less effective in sealing any possible lateral canals or foramen. Similarly, overextending beyond the apex can lead to complications, including the risk of material extrusion into the surrounding tissues, which can provoke an inflammatory response. While ensuring a hermetic seal is critical, the best practice is to avoid compromise of the apical tissues while also achieving an adequate seal at the dento-cemental junction. This comprehensive approach fosters optimal conditions for healing.