A study in the current issue of the journal Anesthesia Progress looked at whether a patient’s level of pain before a root canal changed the effectiveness of local anesthesia. Instead of just focusing on whether patients had pain or were pain free before the surgery, the authors tracked the level of pain to determine whether it affected the success of anesthesia.
In a dental emergency, patients often have acute pain and need a root canal right away. The dentist uses local anesthesia to numb nerves in the area that will be targeted during the surgery. However, these same nerves can be overly active if the patient is in extreme pain. The patient’s lip may be numb, but the standard dose of anesthesia can’t block pain once the dentist’s instruments enter the patient’s mouth.
The current study focused on the lower teeth of more than 175 adults in India. These patients were rated as having mild, moderate, or severe pain in one lower-jaw molar before their root canal. All were given a standard local anesthetic. The injection was considered a failure if the patient continued to feel pain during the root canal procedure.
The authors found that the amount of pain presurgery affected the successfulness of the anesthesia. Patients with more pain before the root canal were more likely to feel pain during the procedure. In the study, 33% of patients with mild pain before the root canal felt no pain or only mild pain during the procedure, but only 16% of patients with severe pain had a painless surgery.
Age and gender did not appear to change the effectiveness of the anesthesia. Instead, all indications were that the more active pain a patient felt before a root canal, the lower the pain threshold for that patient during the surgery.
Dental clinicians need “to take extra measures in giving local anesthesia to patients with severe pain,” said Dr. Vivek Aggarwal, the lead author of the study. “Since such patients are predisposed to a high anesthetic failure rate, a supplementary injection should be given along with a primary injection.”
Full text of the article “Effect of Preoperative Pain on Inferior Alveolar Nerve Block,” Anesthesia Progress, Vol. 62, No. 4, 2015, is now available at http://www.anesthesiaprogress.org/doi/full/10.2344/15-00019.1.
About Anesthesia Progress
Anesthesia Progress is the official publication of the American Dental Society of Anesthesiology (ADSA). The quarterly journal is dedicated to providing a better understanding of the advances being made in the science of pain and anxiety control in dentistry. The journal invites submissions of review articles, reports on clinical techniques, case reports, and conference summaries. To learn more about the ADSA, visit: http://www.adsahome.org/.
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