Local Anesthesia

A dentist must obtain profound anesthesia when providing endodontic treatment. A common mistake that clinicians may make when attempting to get a patient “numb” is to not objectively test whether pulpal anesthesia has been achieved before initiating endodontic treatment. Often, the only determination of whether a patient is properly anesthetized is the “subjective” anesthesia level as reported by the patient. Studies have demonstrated that inferior alveolar nerve (IAN) anesthetic blocks administered to patients with mandibular teeth diagnosed with irreversible pulpitis on average had only a 55% incidence of profound pulpal anesthesia, even in the presence of 100% lip numbness as reported by the patient.13,14

Therefore, before giving local anesthesia for endodontic treatment, the dentist should objectively test the treatment tooth with a cold test and/or EPT. With a preoperative baseline of the pulp sensibility level, after anesthesia is “onboard,” the level of anesthesia can be accessed by re-testing the treatment tooth with cold or EPT (Figure 7). If the post-anesthesia tests are either negative to cold or reveal no response to EPT, there is a high likelihood that profound pulpal anesthesia has been achieved. It is important to note that teeth with metal restorations can provide a false-positive result when using the EPT. Additionally, a study by Fuss et al15 reported that in young patients, the EPT was less reliable than cold tests.

Figure 7.
An electric pulp test (EPT) is used to test a treatment tooth before and after giving local anesthesia to confirm profound pulpal anesthesia.
An electric pulp test (EPT) is used to test a treatment tooth before and after giving local anesthesia to confirm profound pulpal anesthesia.