Which procedure does NOT require the use of short needles?

The correct answer highlights the procedural differences in regional anesthesia techniques. When considering the use of needles in dental procedures, infiltration injections on the maxillary arch typically utilize shorter needles because these injections are designed to deliver anesthetics close to the target area, often within a few millimeters of the oral mucosa. This method is effective for surface-level dental work and requires less penetration.

Monitoring nitrous oxide administration is not directly related to needle use, as this procedure typically involves a mask or nasal cannula for delivering the gas, rather than an injection. Therefore, it also does not require the use of needles at all.

In contrast, block injections on the mandibular arch necessitate the use of longer needles to adequately reach the targeted nerves deeper within the jaw. The technique aims to anesthetize a broader region, requiring a needle that can penetrate further than what is needed for superficial injections.

Combining the understanding of these procedures explains why the block injection on the mandibular arch is the only one that specifically requires longer needles, while infiltration injections and nitrous oxide monitoring do not.