Local Anaesthesia and Recent Advances: A Review

Jasmine Kaur Chandi *

Corresponding Author: Jasmine Kaur Chandi, BDS, Genesis Institute of Dental Sciences and Research, Ferozepur, Punjab, India.

Copy Right: © 2023 Jasmine Kaur Chandi, This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received Date: February 02, 2023

Published Date: February 20, 2023

Abstract

One of the stimuli in the dental operatory that causes the most fear or anxiety is the injection of local anaesthetics. An adequate dental care is said to be hampered by patients' fears of the discomfort that comes with anaesthetic drug injections. Deep local anaesthetic is a key component of paediatric patient treatment success, particularly in terms of reducing their anxiety and discomfort during restorative and surgical treatments.  There are a number of techniques to lessen discomfort during local anaesthetic injections, including topical anaesthetics (such as Benzocaine), warming the local anaesthetic agents, buffering the local anaesthetics, adjusting the rate of the infiltration by slowing down the injection speed, counter-irritation, and distraction technique. 2 This review of literature focuses on the composition, safety dose, adverse effects, and current modifications of local anaesthetic agents and technique

Keywords: Local Anaesthesia, Pain, Recent Advances

Introduction

Since the beginning of time, dentistry has placed a strong emphasis on the effective management of pain.[1] The effective application of local anaesthetic treatments has assisted patients in overcoming their anxiety and dislike of dental procedures. Perhaps the most common cause of patient anxiety is the injection of local anaesthesia, and dental professionals continue to have serious concerns about their capacity to control pain effectively while minimising discomfort. Understanding the drugs being used, the relevant neuroanatomy, recommended practises, and technologies available are necessary for achieving appropriate local anaesthetic. Today's agents and delivery systems for anaesthetics give dentists a variety of alternatives for efficiently controlling the discomfort brought on by dental treatments. [2] This study of literature focuses on the composition, safety dose, adverse effects, and current modifications of local anaesthetic agents and technique.

Composition of Local Anaesthetic Solution:  The local anaesthetic medications now used in clinical practise can be broadly categorised into two classes based on their chemical makeup: (A) medications with ester linkages and (B) medications with amides. The amide category of agents are the ones that are most frequently employed as local anaesthetics in paediatric dentistry. Because of their minimal allergenic properties and better effectiveness at lower concentrations, lidocaine hydrochloride (HCl) 2% with 1:100,000 epinephrine is preferred. [3,4]

Organic salts and potential vasoconstrictors are also included in local anaesthetic carpules. Vasoconstrictors are used to constrict blood vessels, counteract the local anaesthetic’s vasodilatory effects, lengthen its duration, limit systemic absorption and toxicity, and produce a blood-free site for surgical procedures. [5,6]

The maximum recommended dose of lidocaine and mepivacaine is 4.4 mg/kg body weight for lidocaine without vasoconstrictors and 7 mg/kg body weight for lidocaine with vasoconstrictors.  For 20% lidocaine with 1:100,000 epinephrine, pulpal anaesthesia often lasts 60 minutes; for 2% mepivacaine with 1:20,000 levonordefrin, it typically lasts 50 minutes; and for 3% mepivacaine without vasoconstrictor, it typically lasts 25 minutes. The amount of soft tissue anaesthesia in the currently utilised local anaesthetic drugs is greater than the amount of pulpal anaesthesia. [7]

Safety Dose of Local Anesthesia: The local anaesthetic dosage is determined by the patient's physical condition, the area to be numbed, the vascularity of the oral tissues, and the delivery method. A recommended maximum dose for child is challenging to determine because it depends on the child's weight and age. Applying one of the common formulas to paediatric patients younger than 10 years old with lean body mass and appropriate physical development can help establish the maximum dose (Clarks rule). In any case, the maximum dose for ordinary adrenaline and lidocaine with epinephrine should not exceed 4.4 mg/kg and 7 mg/kg, respectively. The cardiovascular and central neurological systems are the primary targets of toxicity; this toxic reaction may either stimulate or depress the CNS.[3]

1.8 mL of local anaesthetic solution (2% lignocaine) are included in the typical dental cartridge. The amount of epinephrine in this cartridge ranges from 1:200,000 (5 g/mL), 1:100,000 (10 g/mL), and as high as 1:50,000 (20 g/mL). The highest volume of LA that can be used safely is 0.35 mL/kg because the maximum dose of LA in combination with epinephrine is 7 mg/kg and the concentration of LA utilised is 2% (20 mg/mL). The maximum amount of LA that can be used in an average 60 kg adult is 21 mL (0.35 mL/kg 60 kg), which equates to 11 cartridges.[8]

The maximum recommended dose of epinephrine per appointment in a dental patient is only 40 g. The 21 mL volume of LA (1:200,000) preparation will deliver 105 g of epinephrine, the 21 mL volume of LA (1:100,000) preparation will deliver 210 g of epinephrine, and the 21 mL volume of LA (1:50,000) preparation will deliver 420 g of epinep Since greater dosages in high-risk cardiac patients undergoing dental procedures can cause systemic vasoconstriction and myocardial ischemia, Therefore, the dose of LA that can be administered safely to cardiac patients undergoing dental work is 2 mL (40 g/20 g mL), 4 mL (40 g/10 g mL), and 8 mL (40 g/5 g mL) with 1:50,000 epinephrine.[8]

Adverse Reaction of Local Anaesthesia: Despite the fact that local anaesthetics can cause anaesthesia in the targeted nerves and anatomical regions, they are nonetheless subject to Paracelsus's dictum that "only the dose produces the poison." In other words, at higher doses, they too can be toxic. There may be unanticipated and serious cardiac and neuralgic effects when systemic concentrations of circulating local anaesthetic rise to a certain level. The nervous system's inhibitory neurons are typically the first to be damaged; when these neurons are blocked, excitatory symptoms including seizures, sensory and visual abnormalities, and muscular poisoning result.[9]

Local anaesthetic seldom causes allergic responses. Procaine is the local anaesthetic that causes allergic reactions most frequently. Para-aminobenzoic acid seems to be one of its antigenic ingredients (PABA). There have been reports of cross-reactivity between lidocaine and procaine. Urticaria, dermatitis, angioedema, fever, photosensitivity, and anaphylaxis are just a few of the many ways that allergies can present themselves. [10,11]

Careful injection technique, vigilant patient observation, and familiarity with the maximum dosage based on weight can all help minimise local anaesthetic toxicity. Practitioners should aspirate before each injection. Effective management depends on the ability to identify hazardous responses early. The local anaesthetic medication should no longer be administered as soon as hazardous signs or symptoms are discovered. The extent of the response determines additional emergency management.[10]

Recent advances in Local Anaesthetic and Devices

Electronic dental anaesthesia:  Based on the well-known Gateway Theory of pain regulation proposed by Malzack and Wall in 1965, electronic dental anaesthesia/transcutaneous electric nerve stimulation (TENS) is a technique that offers us a promising way to induce dental anaesthesia by employing a small quantity of electric current. TENS is frequently employed in a variety of medical and paramedical specialties. Although Shane and Kessler initially documented the use of TENS in dentistry in 1967, there is currently a dearth of material on TENS's uses as an anaesthetic device.[13,14]

Dhindsa A et al. (2011) found a significant reduction in pain during all the dental procedures conducted under TENS, even though comparable with 2% lignocaine injection, and the patient was more comfortable when TENS was used. They found that TENS should be considered as a useful adjunct in the treatment of pediatric patients during various minor dental procedures.[15]

Computer - Controlled Local Anaesthetic Delivery System: There are many new devices available that can provide local anaesthetic to tissues at a predetermined rate. Computer-controlled local anaesthetic delivery (CCLAD) devices are the collective name for these "painless anaesthetic devices." Devices that lower and maintain injection speed as well as maintain a constant speed while taking into account the anatomical characteristics of the tissues being injected are collectively referred to as CCLAD. The Wand® (Milestone Scientific, Livingstone, NJ), Comfort Control Syringe (CCS; Dentsply, USA), QuickSleeper (Dental HiTec, France), and iCT (Dentium, Seoul, Korea) are the most well-known products of this type.[16]

Dentipatch: A 15-minute application of dry mucosa to a dentipatch containing 10-20% lidocaine. Using this patch to achieve topical anaesthetic for injections in the maxilla and mandible was advised by Hersh et al. in their 1996 study on the patch's efficacy. There are drawbacks, such as issues with the cardiovascular and central nervous systems. Shehab LA et al. (2015) effectiveness of the lidocaine Denti-patch ® system versus the lidocaine topical anaesthetic gel in children concerning pain reaction during injection and found Denti-patch ® system can significantly reduce the needle injection pain more than the gel.[17]

Precooling (Cryo Anaesthesia): Precooling is the process of applying cold to a specific area of the body in order to prevent the local nerves from transmitting painful signals.[18] It activates pain-inhibitory pathways by stimulating myelinated A fibres, which in turn raises the pain threshold. Cooling is said to reduce or stop the transmission of pain signals, according to a study.[19] It comes as ice (crushed or cubed ice), refrigerant spray, and other forms. The commercial names for refrigerant spray are Gebauer's Pain Ease and Pharma Ethyl. It takes two to five minutes to apply and has a brief acting duration.[20]

Med-Jet: A needle-free injection system is called Med-Jet. Air compression is used to give injections. By pressing the device's head against the mucosa and letting go of the trigger, solution is forced through the mucosa. Injections can be administered intradermally, subcutaneously, or intramuscularly with a volume of 0.01 to 1 cc at 2000 psi. It causes no pain. It is suitable for pulpal block but insufficient for nasopalatine and larger palatine injections. With pedatric patient, it has great success. Hemorrhage at the site of anaesthetic and high expense are a couple of the downsides. [21]

Intra-osseous anaesthesia:  A local anaesthetic can be injected intraosseously right into the cancellous bone next to the tooth that has to be sedated. Due to the thickness of the cortical plate, infiltration injections with lidocaine solutions are ineffective for numbing the mandibular molar teeth, hence dentists avoid attempting infiltration anaesthesia in the posterior mandible. This issue is solved by the intraosseous injection, which provides easy access to the cancellous bone. To achieve intra-osseous anaesthetic, various systems have been created. All of these techniques inject a local anaesthetic into the cancellous bone next to the tooth's apex. Stabident®, X tip®, and Intraflow® are these systems. [22]

Jet injection: To force the solution out of the aperture in jet-injection technology, pressure is produced with the aid of mechanical energy. It is quick and simple to administer, causes little to no discomfort, causes minimal tissue damage, speeds up drug absorption, and decreases the risk of infection at the location. Because children have reduced bone density, it is mostly useful in children. [23]

Accupal: The Accupal is a cordless, battery-powered tool used for palatal injections and inferior alveolar blocks. In order to condition the alveolar or palatal mucosa, it uses both pressure and vibration. Additionally, it applies pressure and vibrates the injection site in a 360-degree radius around the needle penetration to close the pain gate mechanism and block pain perception. [23]

Conclusion

Dentistry is lucky to have a wealth of resources available to it. Good remedies for preoperative and postoperative pain suffering brought on by the provision of dental care. Injectable anaesthetics have transformed dentistry and produced significant advancements dentistry procedures from the vast majority of patients' perspectives. The capability of the physician to deliver an efficient, secure, and non-traumatic Injecting local anaesthetic into a child's (or adult's) body is a significant component in producing a patient who will accept dental care forever. Instead of shunning local administration out of concern for traumatic the doctor should try to learn about and employ the most recent techniques for managing local discomfort to provide a comfortable experience.

Reference

1. Sharma SS, Sharma A, Saravanan C, Sathyabama. Newer Local Anaesthetic Drugs and Delivery Systems in Dentistry – An Update. IOSR Journal of Dental and Medical Sciences (JDMS). 2012;1(4):10-16.

2. Saxena P, Gupta SK, Newaskar V, Chandra A.Advances in dental local anesthesia techniques and devices: An update. Natl J Maxillofac Surg 2013;4:19-24.

3. Peedikayil FC, Vijayan A. An update on local anesthesia for pediatric dental patients. Anesth Essays Res. 2013 Jan-Apr;7(1):4-9. doi: 10.4103/0259-1162.113977. PMID: 25885712; PMCID: PMC4173488.

4. Troutman KC. Pharmacologic Management of pain and anziety for pediatric patients. In: Wei SH, editor. Pediatric Dentistry Total Patient Care. Philadelphia, PA: Lea and Febbiger; 1985. pp. 156–62.

5. Ananthi Christopher., Shankar, P and Rohini, G.2016, Recent Advances in Local Anesthesia – A Review. Int J Recent Sci Res. 7(10), pp. 13576-13581.

6. Wilson SW, Dilley DC, Vann WF, Jr, Anderson JA. Pain and anxiety control (Partl: Pain perception control) In: Pickham J, Casmassinno PS, Field HW, Mctigue DJ, Nowak A, editors. Pediatric Dentistry, Infancy Through Adolescesce. 3rd ed. Philadelphia, PA: WB Saunders; 1999. pp. 108–15.

7. Malamed SF. Handbook of Local Anesthesia. 5th ed. St. Louis, Mo: Mosby; 2004. Local complications; pp. 285–7.

8. Kothari D, Abbas H. How safe is therapeutic dose of lignocaine with epinephrine: An overview. Natl J Maxillofac Surg. 2015;6(1):132.

9. Sekimoto K, Tobe M, Saito S. Local anesthetic toxicity: acute and chronic management. Acute Med Surg 2017;4:152–60.

10. Jeske AH, Blanton PL. Misconceptions involving dental local anesthesia. Part 2: Pharmacology. Tex Dent J. 2002;119:310–4.

11. Haas DA. An update on local anesthetics in dentistry. J Can Dent Assoc. 2002;68:546–51.

12. Dhindsa A, Pandit IK, Srivastava N, Gugnani N. Comparative evaluation of the effectiveness of electronic dental anesthesia with 2% lignocaine in various minor pediatric dental procedures: A clinical study. Contemp Clin Dent. 2011 Jan;2(1):27-30. doi: 10.4103/0976-237X.79305. PMID: 22114450; PMCID: PMC3220170.

13. Melzack R, Wall PD. Pain mechanism: A new theory. Science. 1965;150:971–8.

14. Shane S M, Kessler S. Electricity for sedation in dentistry. J Am Dent Assoc. 1967;75:1369–75.

15. Dhindsa A, Pandit IK, Srivastava N, Gugnani N. Comparative evaluation of the effectiveness of electronic dental anesthesia with 2% lignocaine in various minor pediatric dental procedures: A clinical study. Contemp Clin Dent. 2011 Jan;2(1):27-30. doi: 10.4103/0976-237X.79305. PMID: 22114450; PMCID: PMC3

16. Kwak EJ, Pang NS, Cho JH, Jung BY, Kim KD, Park W. Computer-controlled local anesthetic delivery for painless anesthesia: a literature review. J Dent Anesth Pain Med. 2016;16(2):81-88.

17. Shehab LA, Basheer B, Baroudi K. Effectiveness of lidocaine Denti patch system versus lidocaine gel as topical anesthetic agent in children. J Indian Soc Pedod Prev Dent. 2015;33:285-90. 

18. Lathwal G, Pandit IK, Gugnani N, Gupta M. Efficacy of Different Precooling Agents and Topical Anesthetics on the Pain Perception during Intraoral Injection: A Comparative Clinical Study. Int J Clin Pediatr Dent. 2015 May-Aug;8(2):119-22. doi: 10.5005/jp-journals-10005-1296. Epub 2015 Aug 11. PMID: 26379379; PMCID: PMC4562044.

19. Mohiuddin, Iqra et al. “Topical application of local anaesthetic gel vs ice in pediatric patients for infiltration anaesthesia.” Journal of Evolution of medical and Dental Sciences 4 (2015): 12934-12940.

20. Ghaderi F, Banakar S, Rostami S. Effect of pre-cooling injection site on pain perception in pediatric dentistry: "A randomized clinical trial". Dent Res J (Isfahan). 2013 Nov;10(6):790-4. PMID: 24379869; PMCID: PMC3872632.

21. Singh Nitin., et al. “Painless anesthesia: A new approach”. Journal of Dentofacial Sciences 2 (2013): 49-55.

22. Reader AL and John Nusstein. “Local anesthesia for endodontic pain”. Endodontic Topics 3.1 (2002): 14-30.

23. Neha Thilak., et al. “Delivery Systems of Local Anesthetics in Dentistry: An Update”. Acta Scientific Dental Sciences 4.5 (2020): 23-27.