List a typical sequence of instrumentation sizes for manual preparation of a moderately curved canal in primary endodontic treatment.

• A. Start with #25–#30 and skip glide path.
• B. Begin with small scouting files (e.g., #10–#15), establish glide path, then enlarge gradually (e.g., #20–#25) while maintaining patency.
• C. Use only #15 indefinitely.
• D. Start with #40–#45.

Answer: (B)

In manual preparation of a moderately curved canal, the essential step is to create a negotiable glide path with small scouting files before any enlargement. Starting with small sizes such as #10–#15 lets you feel the canal, negotiate curvature, and remove obstacles without binding, forming a smooth, reproducible path to the apex. Once a clean glide path is established, you enlarge gradually—around #20–#25 in this context—while actively maintaining patency, meaning you periodically pass a small file to or just beyond the apical constriction to prevent debris blockage. This approach preserves the canal’s natural anatomy, reduces the risk of ledge formation, transportation, or instrument separation, and sets the stage for effective cleaning and obturation. Skipping the glide path or jumping to large sizes from the start increases the chance of mishaps in a curved canal, while using only a small file indefinitely or starting with very large sizes does not provide proper shaping or negotiation.