808 DISCUSSION

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Sicher H, Du Brul EL: Oral Anatomy (ed 5). St Louis, MO, Mosby, 1970

Jorgensen NB, Hayden JS: Premeditation, local and general anesthesia in dentistry. Philadelphia, PA, Lea & Febiger. 1967

Agren E, Danielsson K: Conduction block analgesia in the mandible: A comparative investigation of the techniques of Fischer and Gow-Gates. Swed Dent J 581, 1981

Gow-Gates GAE: Mandibular conduction anesthesia: A new technique using extraoral landmarks. Oral Surg 36:321, 1973

Akinosi JO: A new approach to the mandibular nerve block. Br J Oral Surg 15:83, 1977

Sisk AL: Evaluation of the Akinosi mandibular block tech- nique in oral surgery. J Oral Maxillofac Surg 4: 113, 1986

Montagnese TA, Reader A, Melfi R: A comparative study of the Gow-Gates technique and a standard technique for mandibular anesthesia. J Endod 10: 158, 1984

Berezowski BM. Lownie JF. Cleaton-Jones PE: A comuar-

Sato K: The closed mouth intraoral technique of achieving

ison of two methods of inferior alveolar nerve block. J Dent 16:96, 1988

mandibular anesthesia. Honolulu. HI, Saint Francis Hos- pital, July 28, 1982 (abstr)

22. Malamed SF: The periodontal ligament (PDL) injection: An alternative to inferior alveolar nerve block. Oral Surg 53: 117, 1982

2 1. Rood JP: Some anatomical and physiological causes of fail- ure to achieve mandibular analgesia. Br J Oral Surg 15:75, 1977

Kaufman E, Weinstein P, Milgrom P: Difficulties in achiev- 23. Rood JP: The analgesia and innervation of mandibular teeth. ing local anesthesia. J Am Dent Assoc 108:205, 1984 Br Dent J 140:237, 1976

14. Milgrom P, Weinstein P, Kuafman E: Student difficulties in achieving local anesthesia. J Dent Educ 48:168, 1984

15. Sisk AL: Evaluation of the Gow-Gates mandibular block for oral surgery. Anesth Prog 32:143, 1985

16. Sexton R, Howkins M: Trouble shooting in local anesthesia: Gow-Gates mandibular block. Ont Dent 62:20, 1985

17. Yamada A, Jasstak JT: Clinical evaluation of the Gow-Gates block in children. Anesth Prog 28: 106, 1981

18. Bennett CR: Monheim’s Local Anesthesia and Pain Control in Dental Practice (ed 7). St Louis, MO, Mosby, 1984, pp 99-113

19. Hetson G, Share J, Frommer J, et al: Statistical evaluation of the position of the mandibular foramen. Oral Surg 65:32, 1988

20. Waikakul A, Punwutikom J: Extra-intraoral landmarks tech- nique for inferior alveolar nerve block. J Oral Maxillofac Surg (in press)

J Oral Maxillofac Surg

49:909-909, 1991

Discussion

A Comparative Study of the Extra-intraoral Landmark Technique and the Direct Technique for Inferior Alveolar

Nerve Block

Stanley F. Malamed, DDS University of Southern California School of Dentistry, Los Angeles

Providing clinically adequate pain control in the man- dible has proved to be a problem vexing dentists through- out the world for as long as dentistry has existed as a profession. The classic inferior alveolar nerve block, orig- inally described by Fischer in 1919 and modified over the ensuing years by others, has long been considered the conventional technique for obtaining mandibular anesthe- sia. It was not until 1973, with the publication by Gow- Gates’ of a new approach to mandibular anesthesia, that dentistry began to seriously consider alternatives to the conventional approach. Though not employed by all den- tists, what is known as the Gow-Gates mandibular block has gained a significant foothold in the armamentarium of pain control techniques in the mandible. In an as yet un- published survey of over 3,000 dentists,2 approximately 95% had heard of this technique, with 73% employing it, to some extent, in their practice. Success reported with the Gow-Gates technique has varied from somewhat less than the conventional3 to considerably more.4 The Gow- Gates technique takes into account the fact that the most oft-stated reason for failure to achieve adequate mandib- ular anesthesia is deposition of the solution inferior to the

mandibular foramen, the site at which the inferior alveo- lar nerve enters the mandibular canal and becomes insu- lated from the anesthetic solution. Depositing anesthetic at the neck of the condyloid process in the Gow-Gates technique provides more ready access to V-3 and, with clinical experience, a greater rate of clinically adequate anesthesia than that provided by the conventional tech- nique. Probably the most important result arising from publication of the Gow-Gates mandibular block technique is that it made dentists think about possible alternative approaches to achieving mandibular anesthesia.

Several years later another approach to mandibular an- esthesia appeared-one that purported to provide suc- cessful anesthesia in situations in which the patient was unable (as a result of trismus or mandibular fracture) to open their mouth.’ The Akinosi closed-mouth mandibular block technique is employed by 5% of dentists surveyed’ and usually as a secondary technique to either the con- ventional or Gow-Gates blocks. A significant benefit of the Akinosi technique is that it provides anesthesia of the motor as well as the sensory components of V-3, thereby providing relief from trismus, permitting the dentist to more easily manage the patient’s dental complaints. Be- cause bone is not contacted in the Akinosi technique, its success rate has been found to be somewhat lower than either the conventional or Gow-Gates blocks. However, neither the Gow-Gates nor conventional inferior alveolar nerve blocks can even be attempted when patients are unable to open their mouth.

The incisive (mental) nerve block is another technique that is of importance to dentistry. Profound anesthesia of the premolars, canine, and incisors can be achieved con- sistently (295%) with this injection technique, which is

STANLEY F. MALAMED 809

no more difficult to administer than a supraperiosteal in- jection in the maxilla. With use of the incisive nerve block, it is only the mandibular molar teeth that will prove difficult to anesthetize.6

Waikakul and Punwutikorn have presented yet another approach to mandibular anesthesia: the extra-intraoral landmark technique (EIL). A likely benefit of this proce- dure, for the doctor accustomed to the conventional ap- proach, will be that the landmark for penetration of the needle and the placement of the left (opposite) hand are similar to those of conventional mandibular blocks. Many doctors express some unease at the differences in hand and needle placement found in the Gow-Gates and Aki- nosi blocks. The fact that the users of the technique(s) in this article were predoctoral students may have some impact upon the technique’s success rate. Inexperienced doctors are more likely to “pick up” a new technique of anesthesia more quickly than doctors who have adminis- tered the conventional technique many thousands of times. This was the case when I started teaching the Gow- Gates technique to both student and practicing doctors in 1974. Practicing doctors have to overcome their bias in favor of the “usual” procedure. Initially this leads to lower success rates with the newer technique. The fact that the EIL technique landmarks are similar to those of the older established techniques may prove beneficial to its being accepted.

One item that struck me on reviewing this article was the authors’ recommendation for use of a long dental nee- dle (albeit a 27 gauge, but long nonetheless). A disturbing trend has developed in dentistry, with ever-increasing numbers of dentists reporting the use of short needles for

mandibular blocks in adults.2 The authors measured the soft-tissue depth to bone and reported that with the con- ventional technique, the depth of soft-tissue penetration to the ramus was 20 mm or more in 89.7% of patients, whereas with their EIL technique this was the case in 98.6% of patients. In both techniques the need for a long needle is evident to avoid inserting the shaft of the needle into soft tissue up to the hub and risking irretrievable loss of the needle should breakage occur.

Only time will tell whether this new approach to an old technique will serve dentistry well. If the simple addition of an extraoral bony landmark to the conventional tech- nique proves to be at least as effective and easy to use as the conventional technique, our patient population will be eternally grateful. I look forward to future reports relating the clinical success of this new procedure.

References

1. Gow-Gates GAE: Mandibular conduction anesthesia: a new technique using extraoral landmarks. Oral Surg 36:321. 1973

2. Malamed SF: Survey local anesthesia characteristic of 3000 dentists. (unpublished data)

3. Sisk AL: Evaluation of the Gow-Gates mandibular block for oral surgery. Anesth Prog 32:143, 1985

4. Malamed SF: The Gow-Gates mandibular block: Evaluation after 4275 cases. Oral Surg 51:463, 1981

5. Akinosi JO: A new approach to the mandibular nerve block. Br J Oral Surg 15:83. 1977

6. Walton RE. Abbott BJ: Periodontal ligament injection: A clinical evaluation. J Am Dent Assoc 103:571, 1981