Local Anesthesia
Case presentation
A female patient complains of pain in her third lower molar. She has hyperthyroidism and diabetes. Clinical examination results show that she has severe inflammation around the crown. The treatment prescribed is the surgical removal of the tooth. During surgical extraction of a tooth, the physician subject one to local anesthesia, below are the details about the local anesthesia to prevent pain during the extraction
Type of Local Anesthesia
Due to the risk of thyroid storm, vasoconstrictor epinephrine is contraindicated. The most common local anesthetic agent is 2% lidocaine. These are effective for root treatment for diabetic patients, but glycemic monitoring should be done. Research has shown that the absence of pain following the use of lidocaine has been registered. There are other options like 4% articaine without epinephrine (Lee et al., 2016). Articaine is, however, the drug of choice as it has a slightly longer duration of action despite similar efficacy. Antithyroid medication like methimazole is prescribed earlier before surgery to lower the risk of thyroid storm.
Type of Syringe and Needle Used
The safe dental aspirating syringe is used. Although inventions of new anesthetic drug administration use of a traditional aspirating needle are used. Use of a safety dental syringes in dentistry minimizes the risk of accidental needle stick injury occurring to the health care provider. These syringes contain a sheath that locks over the needle when removed from the patient’s tissues (Saxena et al., 2013). As a local anesthesia delivery device, safe dental syringe and needles are more reliable compared to traditional aspirating syringes and needle in attaining dental anesthesia.
The Nerve Anesthetized
The main aim is attaining an anesthetized mandible for the painless extraction of the third molar. Kim Hwang & Park (2018) explain that the achievement of the anesthetized mandible is the main target. To achieve this, the inferior alveolar nerve, which innervates the mandible from the mandibular canal, must be anesthetized. The other nerves anesthetized are incisor nerve, mental nerve and lingual nerves. The most effective technique to ensure these nerves are anesthetized is approaching the region through mandibular foramen.
The Area Anesthetized
local anesthesia in the extraction of the third molar aims at attaining anesthesia at the following areas, Kim Hwang & Park, (2018), mandibular teeth to the midline, mucus membrane of the insertion area, the body of the mandible, lower part of the mandibular ramus, 2/3 of the tongue, and oral floor. Other parts that are safer when anesthetized are the skin of zygomatic bone, and posterior parts of buccal and temporal areas.
The local Anesthetic Cartridge Used
The efficacy of infiltration is evaluated using various anesthetic agents cartridge, either double or single cartridge model. The local infiltrate technique using the 4% articaine when extracting the third molar. A single cartridge of 1.7ml articaine to take about 19 minutes. This may not be sufficient due to prolonged electric pulp testing response (Sawang et al., 2017). In many cases an additional double cartridge is used.
Maximum Number of Cartridges
After an evaluation of infiltration efficacy using a 1.7 ml single cartridge of 4% articaine in comparison with a 3.4 ml double cartridge in surgery of patients, a double cartridge of 4% (3.4 ml) has a significantly higher success rate compared to a single cartridge for a supplementary local anesthetic. The intraoperative pain was more upper with a single cartridge, thus may require additional anesthesia (Sawang et al., 2017). Therefore third molar surgery is effectively done using a double cartridge model.
Success of Anesthesia
The efficacy of local anesthesia in third molar extraction is not 100% efficient due to the second branch of the trigeminal nerve around the ramus of the mandible. In the maxilla, the success rates are higher due to the complete blockade of the inferior alveolar nerve. A retrospective study determines the success of anesthesia (Fowler et al., 2016). Inferior alveolar nerve block needs supplementation of the buccal infiltration of the molars and premolars; thus hence anesthetic success can be achieved through not high enough to ensure profound pulpal anesthesia.
Reasons for Pain
Pain is associated with ineffective anesthetic therapy at mandibular ramus due to the trigeminal nerve branch. During a traumatic surgical extraction of a tooth increases risk factors for pain (Fowler et al., 2016). Nerve injury of the trigeminal nerve branch is the leading cause of pain during the extraction.
References
Fowler, S., Drum, M., Reader, A., & Beck, M. (2016). The anesthetic success of an inferior alveolar nerve block and supplemental articaine buccal infiltration for molars and premolars in patients with symptomatic irreversible pulpitis. Journal of endodontics, 42(3), 390-392.
Kim, C., Hwang, K. G., & Park, C. J. (2018). Local anesthesia for mandibular third molar extraction. Journal of dental anesthesia and pain medicine, 18(5), 287-294.
Lee, K. J., Park, W., Pang, N. S., Cho, J. H., Kim, K. D., Jung, B. Y., & Kwak, E. J. (2016). Management of hyperthyroid patients in dental emergencies: a case report. Journal of dental anesthesia and pain medicine, 16(2), 147-150.
Sawang, K., Chaiyasamut, T., Kiattavornchareon, S., Pairuchvej, V., Bhattarai, B. P., & Wongsirichat, N. (2017). Double versus single cartridge of 4% articaine infiltration into the retro-molar area for lower third molar surgery. Journal of dental anesthesia and pain medicine, 17(2), 121-127.
Saxena, P., Gupta, S. K., Newaskar, V., & Chandra, A. (2013). Advances in dental local anesthesia techniques and devices: An update. National Journal of maxillofacial surgery, 4(1), 19.