Gow-Gates and Vazirani-Akinosi techniques
The Gow-Gates technique63 has been reported to have a higher success rate than the conventional inferior alveolar nerve block.26, 64 However, experimental studies have failed to show that the Gow-Gates technique is superior.25, 65-67,68 The Vazirani-Akinosi26, 69 technique has not been found to be superior to the standard inferior alveolar injection.65, 70-72 Neither technique is better than the inferior alveolar nerve block in reducing the pain of injection.73 These techniques do not replace the conventional inferior alveolar nerve block. The Vazirani-Akinosi technique is indicated when there is limited mandibular opening (for example, trismus).
Aggarwal and co-authors73a found the Gow-Gates technique was better (52%) than the inferior alveolar nerve block (36%) in patients with irreversible pulpitis. However, the numbers in Aggarwal’s study were small which may have affected the results.
Recently, Click and co-authors73b studied patients presenting with symptomatic irreversible pulpitis and found subjective lip numbness was obtained 92% of the time with the Gow-Gates technique and 63% of the time with the Vazirani-Akinosi technique. The difference was statistically significant (P=.0001). For the patients achieving lip numbness, successful pulpal anesthesia was obtained 35% of the time with the Gow-Gates technique and 16% of the time with the Vazirani-Akinosi technique. The difference was statistically significant (P=.0381). They concluded for patients who achieved lip numbness, neither the Gow-Gates or Vazirani-Akinosi techniques provided adequate pulpal anesthesia for mandibular posterior teeth in patients presenting with symptomatic irreversible pulpitis. Both injections would require supplemental anesthesia. Though this study demonstrated that the Vazirani-Akinosi technique may not be indicated for routine endodontic treatment, it certainly has a useful indication clinically. If a patient experiencing trismus is in need of endodontic treatment, the Vazirani-Akinosi injection may be a valuable primary anesthetic technique. Because the muscles of mastication protectively guard painful mouth opening in patients, the Vazirani-Akinosi technique can result in facilitated mouth opening due to anesthesia of the ipsilateral muscles of mastication or anesthesia of the inflamed/infected tissue. Once an increased opening is achieved, a conventional inferior alveolar nerve block may be administered to the trismus patient if needed.
Incisive Nerve Block at the Mental Foramen Nist and co-authors,74 Joyce and Donnelly,75 Whitworth and co-authors,75a and Dressman and co-authors75b demonstrated the incisive nerve block alone (or an infiltration at the apex of the second molar) was moderately successful in anesthetizing the premolar teeth – but pulpal anesthesia declined after 20-25 minutes. Nist et al.74 and Dressman et al.75b showed that the technique did not anesthetize the central and lateral incisors.
Mandibular Infiltration of a Lidocaine Solution
Labial or lingual infiltrations of a lidocaine solution alone are not very effective for pulpal anesthesia in mandibular teeth.45, 46, 76 A combination of a labial and lingual infiltration will significantly increase success in anterior teeth over either a labial or lingual infiltration alone.77
Meechan et al.78 using 1.8 mL of 2% lidocaine with 1:100,000 epinephrine for either a buccal or buccal plus lingual infiltration of the mandibular first molar resulted in a 32 to 39% success rate (no response to pulp testing).
Mandibular Infiltration of a Lidocaine Solution Following an Inferior Alveolar Nerve Block
Adding a labial infiltration (1.8ml of 2% lidocaine with 1:100,000 epinephrine) to a conventional inferior alveolar injection increases the success of anterior pulpal anesthesia.79
Foster et al.80 found that adding a labial or lingual infiltration injection, using 1.8 mL of 2% lidocaine with 1:100,000 epinephrine, after an inferior alveolar nerve block did not significantly result in more profound anesthesia in the first molar.
One study81 showed articaine was significantly better than lidocaine for a primary buccal infiltration of the mandibular first molar. Articaine only had a 64% success rate (two consecutive 80 readings with the electric pulp tester). Jung et al.82 and Corbett et al.82a also used a primary first molar buccal infiltration of an articaine formulation and found a 54% and 64 to 70% success rate respectively. Another study83 found an 87% success rate (two consecutive 80 readings with the electric pulp tester) for a primary articaine buccal infiltration of the mandibular first molar versus a 57% success rate for a lidocaine solution. The duration of pulpal anesthesia declined over 60 minutes for both anesthetic solutions. Nydegger and co-authors83d found that a 4% articaine formulation was statistically better than both 4% lidocaine and 4% prilocaine formulations for buccal infiltration of the mandibular first molar in asymptomatic mandibular first molars. Rather than a 4% concentration, it is likely the chemical structure of articaine results in better anesthesia for mandibular buccal infiltrations. However, the success rate of 55% was not high enough to support its use as a primary buccal infiltration technique in the mandibular first molar. Therefore, the superiority of articaine over lidocaine may be related to the intramolecular hydrogen bonding allowing better bone penetration.83a
Mandibular Incisor Infiltration of an Articaine Solution
Jaber et al.83b found 4% articaine was more effective than 2% lidocaine (both with 1:100,000 epinephrine) in anesthetizing mandibular incisor teeth after labial or labial plus lingual infiltrations. However, neither solution sustained anesthesia for 45 minutes. Nuzum and co-authors83c found the labial infiltration of a cartridge of 4% articaine with 1:100,000 epinephrine plus a supplemental lingual infiltration of a cartridge of 4% articaine with 1:100,000 epinephrine significantly improved the success rate (no response to two consecutive 80 readings with the pulp tester) to 98% when compared to a labial infiltration of a cartridge of the same articaine formulation (76% success). The combination labial and lingual infiltrations did not provide pulpal anesthesia for an hour. An option would be to administer an inferior alveolar nerve block and then add articaine infiltrations in the anterior teeth to increase success.
Mandibular First Molar Infiltration of an Articaine Solution Following an Inferior Alveolar Nerve Block in Asymptomatic Subjects
Haase et al.84 in a prospective, randomized, double-blind, crossover study comparing the degree of pulpal anesthesia achieved by means of mandibular first molar buccal infiltrations of two anesthetic solutions: 4% articaine with 1:100,000 epinephrine and 2% lidocaine with 1:100,000 epinephrine following an inferior alveolar nerve block found 4% articaine with 1:100,000 epinephrine, resulted in a higher success rate (88%) than 2% lidocaine with 1:100,000 epinephrine (71% success rate). Success was defined as achieving two consecutive 80 readings within 10 minutes following the inferior alveolar nerve block plus infiltration injections and the 80 reading was continuously sustained through the 60th minute.
Kanaa et al.84a found a 91% success rate (two consecutive 80 readings with a pulp tester) of the mandibular first molar when 4% articaine with 1:100,000 epinephrine was added as a supplemental buccal infiltration after an inferior alveolar nerve block.