Patients sometimes report that it is difficult for them to achieve adequate “numbness” for routine dental procedures.  Fortunately, there are a variety of local anesthetics as well as various techniques for delivering them.  It is a very rare occurrence when we cannot find some combination of anesthetic and technique to help our patients to feel adequately ‘frozen’.  There are, however, some very interesting reasons why patients may have such problems.  Most of these can be prevented once the causes are understood.

Anything that causes the pH, or acidity level, of the body to be abnormal can result in poor anesthetic performance.  These agents require a very narrow pH range in order to be effective.  So, if a patient is taking high levels of vitamin C, for example, the body’s pH may be too low, or acidic.  For these patients, stopping vitamins for two days before their appointment could be helpful.  Also, when a patient has a dental infection, the pH in the area of the infection may be low, requiring additional anesthetic or a different method of delivering it.  It would be much better to have the problem treated before it becomes a full-blown acute infection, but if this isn’t possible, we will have patients begin antibiotic therapy for a couple of days before proceeding with necessary treatment.  If a problem is suspected, have it checked out sooner rather than later to avoid unnecessary discomfort, expense, and loss of time.

Similarly, if a person grinds or clenches, the muscles may have a buildup of lactic acid like when we exercise any muscle heavily.  In this case, the pH is thrown off due to the accumulation of the lactic acid.  Such patients will benefit by chewing 4-6 regular TUMS tablets with plenty of water the night before their dental appointment, and again 4-6 tablets of TUMS the morning of the appointment. This changes the level of acidity of the body to allow the dental anesthetic to work better.

Others experience anesthetic that does not seem to last long enough.  Sometimes, one’s metabolism can be in high gear contributing to the short-lived effects of the anesthetic.  For example, patients who are very nervous may have this issue.  Similarly, those who have had significant caffeine or vigorous exercise prior to their appointment may have the same problem.  Limiting the coffee or energy products and physical activity on the day of your dental appointment will be helpful.  For those who are very nervous, a mild oral sedative may be the solution. Another choice in our office would be what is commonly known as ‘laughing gas’ or nitrous oxide sedation during dental treatment, which you can read about on our website.

A small group of patients may have a rather rare genetic disorder called Ehlers-Danlos Syndrome which affects various tissues in the body.  These patients may experience joint hypermobility, stretchy skin and may be easily bruised.  These patients also may not become adequately numb for dental procedures.  These patients may need additional anesthetic as well as more frequent doses, and in some cases, they must be treated with intravenous or general anesthesia for basic dental treatment.

Believe it or not, there is some evidence that people with red hair may have more difficulty achieving adequate numbness!  The same gene which results in red hair and fair skin is the culprit.  Redheads may just need additional anesthetic to feel adequately numb.

Here are some basic rules to follow to insure the best result from your local dental anesthetic:

  1. Have a restful night’s sleep before your dental visit.
  2. Do not rush around and try to do a day’s work in a couple of hours before your visit. Also, no vigorous exercise within a few hours of your appointment.
  3. Avoid caffeine products especially the day of your visit.
  4. If you have had difficulty achieving adequate numbness in the past, try taking Tums™ before your appointment.
  5. Talk to your dentist about your experiences with anesthetics as well as any concerns you may have.

Dr. Frederick Joubert is a cosmetic and family dentist in practice in Charlotte, NC. If you have dental questions, you can call him at 704-544-9199. Please also feel free to leave comments or questions below, and Dr. Joubert will be happy to answer!

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Our Location

Arboretum Family Dentistry
3135 Springbank Ln #210
Charlotte, NC 28226
Phone:(704) 544-9199


Monday - 8:30 am - 5:00 pm
Tuesday - 8:30 am - 5:00 pm
Wednesday - 8:30 am - 5:00 pm
Thursday - 8:30 am - 5:00 pm
Friday - Closed

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