Trismus – a limited range of motion of the mouth.
Sometimes called lockjaw due to association with tetanus in the early days may be caused by a variety of other reasons.
Limited movement of the mouth, any restriction in the opening of the mouth, or limited range of motion falls under the name of trismus. It usually results in spasms of the muscles and may be caused by a variety of things, such as infection, impacted wisdom tooth, removal of a wisdom tooth, joint problems, trauma, adhesions or scarring, tumors and many other possibilities such as radiation. Trismus may occur after a lengthy series of radiation treatment especially if it near the temporomandibular joint. On a rare occasion, a dental injection may cause a small hematoma or bruise which results in trismus.
In most cases, the symptoms are severe at the onset yet often self-limiting. It is helpful to apply moist heat, non-steroidal anti-inflammatory drugs such as over-the-counter Ibuprofen, Aleve, Advil, Motrin, Naproxen, Tylenol, or Aspirin. These work by reducing the discomfort and lessening any associated inflammation. Muscle relaxants my also be utilized and exercise and massage are quite beneficial.
Although significantly rare now, trismus, another name for tetanus, was usually caused by a puncture wound which later became infected. It was normally a nail or a cut by a wire which was the cause of the puncture. The term “lockjaw” was associated then with tetanus and now trismus.
Trismus, or any other restriction in the opening of the mouth, may result in difficulties with oral hygiene, such as brushing and flossing, as well as eating. Often a smaller-sized tooth-brush is required, and a slight change in diet may become necessary, such as liquid or softer food. The proper nutritional intake should always be maintained. That being said, if you have a case of trismus, you should carefully and slowly chew your food more than normal to avoid choking from swallowing too large a bolus of food.
One of the easy treatments for trismus is the “triple 7” exercise. This means open your mouth as far as you can 7 times for 7 seconds and do this 7 times per day. You may use your fingers to help open your mouth and it also helps to move the jaw to each side as far as you can for about 3 seconds. Each time the amount of opening should slowly increase. You can start with this number and progress with more repetitions as the condition improves. Do not stretch open enough to cause significant pain! Remarkable improvement will be immediately noticed but that improvement will dissipate if the exercises are not continued. You eventually should be able to insert three fingers stacked together in your mouth.
Most cases are from dental injections as a result of sometimes getting a hematoma which rarely occurs. A few cases are a result of wisdom tooth extractions. Fortunately these conditions are usually self-limiting with little or no treatment. One still must be cognizant of the other possibilities.
Life Member of American Dental Association, Emeritus Fellow of Academy of General Dentistry, American Association of Implant Dentist