What is the best method to confirm pulpal anesthesia before beginning endodontic treatment?

Lip numbness confirms inferior alveolar nerve (IAN) block anesthesia of the nerve trunk, but does NOT confirm pulpal anesthesia of the tooth. Studies have shown that up to 44% of molars with irreversible pulpitis can remain sensitive to cold testing even after a successful IAN block (as confirmed by lip numbness). The cold test directly confirms that the individual tooth's pulp is anesthetized. Gingival probing confirms soft tissue anesthesia only. Tongue numbness indicates lingual nerve anesthesia. Pulpal anesthesia must be confirmed by a negative response to the cold test on the specific tooth.