SO MANY DENTAL ANAESTHESIA TECHNIQUES...WHAT TO CHOOSE?

01-12-2021

Local anaesthesia is considered the most effective and safest method for pain control in dentistry. Dentists can choose from a range of techniques to anaesthetise nerves in the oral cavity. The region of the oral cavity that requires numbing dictates which technique is chosen. Sometimes, one technique is more effective than another. Additionally, certain techniques are also available to make the injection of local anaesthetic a more comfortable experience for patients, and novel anaesthesia techniques are emerging.
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TECHNIQUES FOR MANDIBULAR ANAESTHESIA

Techniques for mandibular anaesthesia include: 
  1. The inferior alveolar nerve block (IANB) - this is a frequently used technique in mandibular anaesthesia [1]. However, it is not an easy technique and has one of the highest percentages of failure. IANB is used to numb [2]:
    · Teeth on one side of mandible
    · A dense layer of vascular connective tissue (periosteum) of the mandible 
    · Lingual soft tissue
    · Some anterior inner lining of cheek (buccal) soft tissue
    · Bone from the inferior portion of ramus to the midline

  2. The Gow-Gates mandibular nerve block – this technique was developed to overcome the failure rate of IANB. One study reported a mandibular anaesthesia success rate of 99% [3]. It is also reported to have a lower risk for positive aspiration than IANB. 

  3. Vazirani-Akinosi - this is an alternative technique for IANB and the Gow-Gates technique [4]. It is also commonly known as “tuberosity approach” and “closed mouth mandibular nerve block”. It is used when the patient has a limited range for mouth opening or spasms in the masticatory muscles.

  4. The Buccal nerve block – this technique induces anaesthesia to the buccal gingiva, mucosa, and an area of the cheek in the mandibular molar region with a success rate of 100 percent [5]. The buccal nerve is not anaesthetised when using IANB.

  5. Mental and incisive nerve block - this is a technique used to anaesthetise the terminal branches of the inferior alveolar nerve. One main difference is that the incisive nerve block requires the application of pressure to direct the anaesthetic solution in the right direction [6].
 

MAXILLARY ANAESTHESIA TECHNIQUES

Techniques for maxillary anaesthesia include:
  1. Supraperiosteal injection - commonly referred to as “local infiltration”, this is a frequently used technique that achieves pulpal anaesthesia. It is an easy technique with high success rates [7]. However, a regional nerve block is more effective when multiple teeth require anaesthesia, or if inflammation or an infection are present [2]. Paediatric patients benefit from infiltration for anaesthetising mandibular primary teeth.

  2. The maxillary nerve block – this technique is meant to anaesthetise the hemimaxilla. It can be achieved through several approaches such as high tuberosity approach, greater foramen approach, posterior superior alveola nerve block, middle superior alveolar nerve block, anterior superior alveolar nerve block, greater palatine nerve block, nasopalatine nerve block, anterior middle superior alveolar nerve (AMSA) block, and palatal anterior superior alveolar nerve block [1, 8, 9].
 

NEW AND UNCONVENTIONAL TECHNIQUES

While pharmacological local anaesthetics remain the staple for anaesthesia in dentistry, new techniques have, and are, being developed. Consider the following examples:

  1. Electronic dental anaesthesia is a technique in which electronic waves block transmission of pain to the brain [6]. 

  2. PED-O-JET, SYRIJET and MED-E-JET are needle-free injection systems that use piston pressure and produce less pain than normal injections. Phobia of needles is common among patients. A needle-free injection could ease the apprehension associated with dental procedures. 

  3. Iontophoresis is a technique that administers lidocaine transdermally. Electrodes on the skin control the passage of ionized lidocaine into the dermis [10]. 

Computer-controlled injection, although costly, controls the speed and pressure of an injection and provides less discomfort for the patient [6]. 

TECHNIQUES TO ENHANCE THE PATIENT EXPERIENCE

Several techniques or “tricks” can be employed to increase the comfort of patients. Some dentists suggest that warming local anaesthetics to corporal temperature (37°C) decreases the pain of injection [11]. However, warming local anaesthetics to corporal temperature is not recommended [12, 13]. Given that heat degrades the vasoconstrictor in the formulation, room temperature storage conditions (20-22°C) are sufficient [14]. An additional method used to decrease pain of injection is “buffering” [15]. This is the process of increasing the acidic pH of the anaesthetic solution before injection. Buffering also increase the onset of anaesthesia.

Choosing the right technique can increase the effectiveness of anaesthesia while increasing patient comfort. In turn, patients are less likely to have a negative association with dental procedures. This makes patients more likely to return to the same dentist and seek oral treatment in a timely manner.

REFERENCES:
1. Handbook of Local Anesthesia, 6th Edn. S. F. Malamed (editor). Published by Mosby, MO, USA.
2. https://www.intechopen.com/chapters/47578#B1
3. George A.E. Gow-Gates, Mandibular conduction anesthesia: A new technique using extraoral landmarks, Oral Surgery, Oral Medicine, Oral Pathology, Volume 36, Issue 3, 1973, Pages 321-328, ISSN 0030-4220.
4. Akinosi JO. A new approach to the mandibular nerve block. Br J Oral Surg. 1977 Jul;15(1):83-7. doi: 10.1016/0007-117x(77)90011-7. PMID: 268212.
5. Oral and Maxillofacial Surgery. Lars Andersson, Karl-Erik Kahnberg, M. Anthony Pogrel. Published by Wiley Blacwell.
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3468291/
7. Oulis CJ, Vadiakas GP, Vasilopoulou A. The effectiveness of mandibular infiltration compared to mandibular block anesthesia in treating primary molars in children. Pediatr Dent. 1996 Jul-Aug;18(4):301-5. PMID: 8857658.
8. Friedman MJ, Hochman MN. A 21st century computerized injection system for local pain control. Compendium of Continuing Education in Dentistry (Jamesburg, N.J. : 1995). 1997 Oct;18(10):995-1000, 1002-3; quiz 1004. PMID: 9533309.
9. http://www.quintpub.com/userhome/qi/qi_29_5_friedman_3.pdf
10. Wanasathop A, Li SK. Iontophoretic Drug Delivery in the Oral Cavity. Pharmaceutics. 2018 Aug 7;10(3):121. doi: 10.3390/pharmaceutics10030121. PMID: 30087247; PMCID: PMC6161066.
11. Bainbridge LC. Comparison of room temperature and body temperature local anaesthetic solutions. Br J Plast Surg. 1991 Feb-Mar;44(2):147-8. doi: 10.1016/0007-1226(91)90050-t. PMID: 2018901.
12. Meechan JG, Day PF. A comparison of intraoral injection discomfort produced by plain and epinephrine-containing lidocaine local anesthetic solutions: a randomized, double-blind, split-mouth, volunteer investigation. Anesth Prog. 2002 Spring;49(2):44-8. PMID: 15384291; PMCID: PMC2007391.
13. Rood JP. The temperature of local anaesthetic solutions. J Dent. 1977 Sep;5(3):213-4. doi: 10.1016/0300-5712(77)90006-9. PMID: 269144.
14. Handbook of Local Anesthesia, 7th Edn. S. F. Malamed (editor). Published by Mosby, MO, USA.
15. Malamed SF, Falkel M. Advances in local anesthetics: pH buffering and dissolved CO2. Dent Today. 2012 May;31(5):88-93; quiz 94-5. PMID: 22650087.