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Mouth Diseases

TMD Symptoms Following Root Canal Therapy

08/31/2011

Question:

More than a week after a root canal procedure in an endodontist’s office, I am suffering many of the symptoms commonly associated with TMD (temporomandibular joint disorder). I have not had any jaw problems previous to this dental procedure.

Can multiple injections of a local anesthetic trigger TMD symptoms such as lower jaw pain and difficulty opening the mouth to eat normally?

Answer:

There may be number possible causes to explain your symptoms.

1. Endodontic therapy requires that you keep your mouth open with a rubber protective "Dam" for long periods of time (45 minutes or longer at one setting). Most dentists will provide their patients with a rubber bite block to bite down on to act as a rest for the teeth and jaws. Keeping your mouth open for so long possibly caused hyperextension of the muscles and ligaments associated with mastication and temporal mandibular joint function.

It is likely that you are experiencing a combination of myofascial pain or muscle soreness related to keeping your mouth wide open for a long period of time.

2. Inferior Alveolar Injections and TMJ symptoms can occur post root canal therapy but usually arise simultaneously after treatment or rather injection. The location where the injection is made is the opening or "foramen" where the inferior alveolar nerve artery and vein enter on the medial aspect of the ramus of the mandible.
 
If you were to open your mouth and stick your thumb back behind the last tooth on the jaw and grasp the back of the jaw, where your thumb rests, is the area where the needle is inserted.

Sometimes the needle will hit the jaw bone or nick the vessels and a little bruise (hematoma) can occur. In some isolated cases the bleeding can leak out into the muscle and facial spaces and cause problems with opening and chewing because of the associated swelling.

Also sometimes the injection results in trauma to the nerve itself and lip numbness or tingling (parathesia) can also result. Problems associated with local anesthetics and injections though occur sooner than 1 week, and resolve with time.

3. I would contact your dentist and let them know of your symptoms and concerns. Let them evaluate the muscles and joint apparatus. I would strongly recommend very conservative treatment modalities and let time assist in resolution of the problem.

In the meantime you can avoid chewing gum, smoking, drinking lots of caffeine, chewing very chewy foods (caramels), opening as wide as you can to eat apples or corn on the cob.

Your dentist may have you take NSAIDS, and either apply a cold compress or heat depending upon what they find at examination.

I hope this helps.

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Response by:

Richard J Jurevic, DDS, PhD Richard J Jurevic, DDS, PhD
Formerly, Assistant Professor of Biological Sciences
School of Dental Medicine
Case Western Reserve University