Some people have an easy time getting numb, and some don’t.

On the easy end of the spectrum, I have one patient who is extremely sensitive to drugs. I give her half a carpule of an anesthetic without epinephrine (a vasoconstrictor which helps to keep the anesthetic in the area), and she gets numb in 30 seconds, and I can work on her teeth for an hour. And this is for the lower jaw which is harder to numb for than the upper teeth.

On the other side, some patients have a difficult time getting numb, more so on the lower. If someone has an infection, the pH of the tissues in that area becomes more acidic and the anesthetic doesn’t work nearly as well in that environment. This is more important when someone is having a surgical procedure like a tooth extraction or when having a root canal done on an infected tooth. Sometimes the clinician will put a patient on antibiotics to help get the infection controlled to some degree, and then the procedure will be easier on doctor and patient alike.

For routine restorative procedures (fillings and crowns), there can still be some difficulty getting numb. What are the doctor’s options?

There are different options of anesthetic. The traditional option is to use lidocaine 2% with 1:100000 epinephrine. This is what was used in dental school when I studied in the late 1970’s and is still the most common to use today. When this doesn’t do the job, I like to use Septocaine 1:200000 epinephrine. This is a longer lasting choice but works quite well. There is some concern that a patient could have a permanent paresthesia from this product, but the only documented cases are with Septocaine 1:100000, and there are very few of those. I still like this when the occasion arises.

There is an option for no epinephrine if the epinephrine makes the patient’s heart race. I have found that there are more patients that don’t get numb enough with this, and sometimes the Septocaine 1:200000, with half the epinephrine, works well without the heart racing.

There are also longer lasting options which are used more often in surgery.

Instead of using a different anesthetic, sometimes a different location for injection can be used. There is the basic technique for numbing the lower arch, and then there are some modifications of how to get the anesthetic where it is going to work better. One of the techniques is known as Gow-Gates, named after an Australian dentist who invented this helpful technique. There is also a technique where the anesthetic is injected into the bone. It may sound horrible, but it is a lot easier and works well for root canal teeth that are difficult to get numb because of the severe pain.

I am still waiting for the inhaler version of local anesthetic. The plan is that the patient breathes in the anesthetic and gets the upper teeth numb, and possibly even the lower teeth. What a great idea!. Although this has not passed all of the steps for FDA approval, it is still in the works.