Skip to Main Content

Effective Anesthesia

Tips to Increase the Chance of Effective Anesthesia

Things are always moving ahead in science, and dentistry is no exception. Recently, I ran across an interesting bit of information in The Journal of the Canadian Dental Association (JCDA). This is a little tidbit of useful knowledge from an instructor named Dr. Andrew Nette at Dalhousie University in Nova Scotia.


Anesthesia is difficult technically and a lot less reliable in the lower molar region than in other areas of the mouth. The anesthetic is placed deep and there are many factors that combine to make achievement of profound anesthesia less reliable than elsewhere. Many of these factors are outside of the control of the dentist and the patient. We have covered this before in this series of articles. The most important factor that is under our control is wide opening on the part of the patient. At the best of times (mouth open 40mm or more), a single injection of anesthetic for lower molars is about 80% effective. When the patient either can’t or won’t open beyond 25 millimeters the chance that one injection is going to be effective in the lower molar region drops to only about 50%. Inadequate anesthesia will necessitate either another injection (or more) or suffering on the part of the patient.

Now there’s more on this from Dr. Nette in Nova Scotia. Relaxation of the neck makes the injection more effective--meaning a higher percentage of first injections are effective. He found that it is difficult for most people to relax the neck. However, nearly everyone is able to relax the shoulders and just sort of let go. Shoulder relaxation also relaxes the neck and the buccinator muscle. Not only is the anesthesia more effective, it is more comfortable. There is really no down side to this suggestion. Relax your shoulders when you need anesthetic injected to numb your lower molars.

This is a simple modification of anesthesia technique that will make your visit to the dentist more comfortable and the dentist’s day easier—and it’s painless and without cost. And best of all, even if your dentist hasn’t heard about this little change, you can do it yourself. Just relax your shoulders when anesthetic for lower molars is being injected.

Make sure you ask your dentist if you want to know more about dental anesthesia.

- This article was written by Dr. Mike Christensen and published in the Daily Miner and News, and Enterprise. Local Kenora News Publicatons (1998-2006)

(807) 468-8966