Regional Block

When giving a regional block, such as an IANB, the dentist should administer 1 cartridge of an anesthetic and then wait a few minutes to observe whether the patient reports any subjective signs (“feeling numb” or “feeling my lip or cheek is fat”).

If the patient states that he or she feels the anesthetic is taking effect, the clinician did not miss the anatomical block and should proceed with testing the tooth for numbness. If the patient does not report “feeling numb” or any other subjective equivalent, it is a sign that either the anatomical block was missed or there was not enough concentration of base “onboard” to penetrate the nerve sheath and the clinician should inject another cartridge of anesthetic. If lip numbness occurs but the tooth is still responding to testing, the clinician should move on to administration of supplemental injections.

Since the introduction of articaine into the US market, there have been studies that have demonstrated there is no significant difference between 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine in IANB anesthesia.^16,17 It is important to note that studies have reported a higher incidence of paresthesia when articaine has been administered for IANB. Although the exact etiology of the paresthesia is unknown, it is hypothesized that the neurotoxicity may be due to the higher concentration of local anesthesia used: 4% articaine as compared with 2% lidocaine.^18,19 The clinician must consider these risks along with the benefits of administering 4% articaine for IANB anesthesia.