Which tool is primarily used during the gingival sulcus measurement?

The probe is primarily used during gingival sulcus measurement because it is specifically designed to assess the depth of the gingival sulcus, which is the space between the tooth and the gum. The probe has markings that allow the clinician to accurately measure this depth, providing essential information that can help in diagnosing periodontal health. Measurement with a probe is critical for identifying the presence of periodontal disease, as deeper sulcus depths can indicate inflammation and attachment loss.

In contrast, other tools like the scaler are used for removing calculus and plaque from tooth surfaces but are not intended for measuring sulcus depth. The explorer serves to detect cavities or irregularities on tooth surfaces but does not provide a means to measure gingival sulcus depth. The mirror is primarily used to enhance visibility in the mouth but does not have any measuring capabilities. Each tool has its own specific purpose, making the probe the most suitable for this particular task.