Which tool would most likely be used to assess the depth of a cavity?

The explorer is specifically designed for assessing the depth of cavities and identifying any decay in the tooth structure. It has a pointed tip that allows dental professionals to feel and inspect the surface of the tooth carefully. This tool is particularly useful for detecting carious areas and for determining their extent, enabling the practitioner to decide on the appropriate treatment.

When cavities are present, the explorer helps to ascertain not only the depth but also the texture and condition of the affected tooth enamel and dentin. A thorough examination using an explorer can inform the clinician of the right restorative procedure needed to treat the cavity effectively.

In contrast, other instruments like the probe, scalpel, and mouth mirror serve different purposes in dental practice. The probe is often utilized for measuring periodontal pockets rather than cavity depth. The scalpel is primarily used for surgical procedures involving soft tissue, and the mouth mirror is utilized for visibility and indirect vision but doesn't provide a means to measure cavity depth. Understanding the specific functions of these tools highlights why the explorer is the most suitable choice for assessing cavity depth.