Smaller anesthesia needle bore fails to reduce pain

A local anesthetic is often given during dental work to lessen pain, but for many patients the anesthesia injection is as bad or as scary as the experience of dental treatment itself. Dentists are constantly looking for ways to reduce the pain produced by injecting the numbing agent.

An article in the current issue of the journal Anesthesia Progress describes a novel needle design that attempts to reduce such pain. This new dental needle has the same outside diameter as a standard needle, but the opening inside the new needle is larger. The authors speculated that this larger opening inside the needle might decrease the pain of both inserting the needle as well as injecting the anesthetic liquid.

ADDITIONAL READING |Addition of ATP to midazolam offers enhanced dental sedation, fewer adverse effects

Many patients avoid visits to the dentist because they fear pain, which dentists have for decades attempted to reduce, first with general anesthesia, and now mainly with local anesthesia. While generally effective, this injection can still be painful for patients. Many attempts have been made to diminish injection pain, ranging from smaller needles and topical numbing agents to distracting the patient in various ways.

ADDITIONAL READING |Dual anesthetics preferred by most U.S. dentist anesthesiologists

In the current study, 20 dental patients were given four anesthesia injections on both sides of the mouth using two types of needles from Septodont. The locations chosen for the injections are commonly used for dental anesthesia. The new larger inner bore needle was used on one side of each patient’s mouth, and a standard inner bore needle was used on the other. Patients then rated the amount of pain they felt.

The authors found that the larger opening inside the needle did not decrease pain while the needle was inserted or while the anesthesia was injected. Compared to the standard-bore needle of the same gauge, there was no significant difference in the amount of pain reported by the patients.

The same patient received injections using both inner bore sizes (the outer bore being the same size) and rated the pain immediately after the anesthesia was injected. The injection rate was carefully controlled so that it did not affect the level of pain experienced by the patients. Half of the patients received injections using the larger inner bore needle first and half had their first injections from the standard inner bore needle, so injection order did not appear to be a factor in the patients’ pain ratings.

The authors noted that this is the first published study to assess the effect of inner needle bore size on pain with anesthetic injections, so independent studies are needed to confirm their finding. Although this attempt to decrease pain was not effective, dentists continue to try to find ways to improve the experience of dental treatment that is still very disconcerting for many people.

Full text of the article “Effect of needle design on pain from dental local anesthetic injections,” Anesthesia Progress. 2014;62(1) is now available here.

For more information about Anesthesia Progress, visit their website.