Answer to Question of Feb 02

Option B.

Rationale: Apical patency is established during root canal preparation with the purpose of maintaining access to the foramen (mechanical goal), but it is important that after instrumentation the foramen is not only patent but also clean (biological goal). A patency file, which should have a smaller diameter than the foramen, will probably not do this cleaning properly. The use of an instrument that binds to the foramen and touches all root canal walls will certainly be more indicated. Therefore, the best approach would be to ensure apical patency with a file of smaller diameter during instrumentation and then clean the foramen with a file that binds to its walls.