Final answer:
The Periodontal probe is the primary instrument used in periodontal procedures to measure pocket depths and assess gum health.
Step-by-step explanation:
The instrument that is used primarily in periodontal procedures to measure the depth of periodontal pockets is the Periodontal probe. This tool is used by dentists or dental hygienists to assess the health of the periodontium, the specialized tissues that both surround and support the teeth. A periodontal probe can help in diagnosing gum diseases and in planning treatment, as it measures the pocket depths around a tooth to establish the state of health of the periodontium. Other instruments like scalpels, forceps, and surgical curettes are also used in periodontal procedures but serve different purposes such as cutting, grasping, and removing tissue respectively.