Some side effects of radiation, like hair loss and vomiting, are common knowledge, but other side effects are less well-known. You may not know that radiation can cause a lot of side effects inside your mouth. Radiation can cause trismus, commonly known as lockjaw. Here are five things radiation patients need to know about this unpleasant complication.

What are the signs of lockjaw?

Lockjaw can develop three to 12 months after the conclusion of radiation therapy, and the condition may continue to get worse over the next 24 to 48 months. You will notice that your jaw feels stiff and that you have a limited range of motion in your jaw. You may have trouble opening your mouth wide enough to eat or drink. If you notice these signs after undergoing radiation therapy, make sure to talk to your dentist as soon as possible.

How does radiation cause lockjaw?

Radiation therapy works by targeting and killing cancer cells, but unfortunately, this treatment can also cause damage to your healthy cells. If you undergo radiation therapy for a head or neck cancer, your jaw hinge and the muscles that control it may be damaged by radiation. This radiation leads to the buildup of a protein called fibrin within the radiated tissue. As the fibrin accumulates around your jaw hinge, it can prevent you from opening your jaw fully.

Why is lockjaw serious?

Lockjaw makes it very hard for you to talk or eat, but it is much more than just an inconvenience; lockjaw can have serious effects on your dental health. If you're not able to open your mouth normally, it will be difficult or even impossible for you to brush and floss your teeth. Cavities can develop fairly quickly in the total absence of oral hygiene. If you're not brushing or flossing your teeth at all, you can develop cavities in as little as three weeks. Cavities, if they're left untreated, can become infected. This infection can spread deeper into your jawbone, and in severe cases, the bone can die.

Even when you aren't able to open your mouth, you still need to make sure that your teeth are getting clean. This is very difficult, but with the help of your dentist, you can continue your oral hygiene routine and stave off cavities.

How can your dentist help you?

Lockjaw that forms in response to radiation therapy is irreversible, so your dentist will not be able to cure you. However, your dentist can help you avoid the oral health complications associated with lockjaw.

If you can't open your mouth wide enough to use a toothbrush, your dentist may recommend rinsing your mouth after meals with mouthwash or a saltwater solution. If traditional flossing is impossible, your dentist may recommend alternative methods such as a water flossers that may be easier to fit in between your teeth.

Professional teeth cleanings are another way that your dentist can help you avoid cavities and other problems. Depending on the range of motion that you have in your jaw, they may only be able to clean the front surfaces of your teeth, but this is still better than nothing.

How common is lockjaw among radiation patients?

Lockjaw is a very common complication of radiation therapy. Between 35% and 55% of radiation patients develop lockjaw. The risk is highest for people who are undergoing radiation therapy for cancers of the oral or nasal cavities, as well as people who are receiving high doses of radiation or are undergoing multiple courses of radiation therapy.

If your jaw feels stiff after radiation therapy, and you're having trouble brushing or flossing, make an appointment at a dental clinic like Centre Family Dentistry as soon as possible.