Radiation Therapy Considerations

Section 2: Dental Considerations for Radiation Therapy Patients

(This page is intended for informational purposes only and must not take the place of adequate dental examination, diagnosis, and treatment.)

Radiation therapy kills cancer cells by shrinking blood vessels in the affected area. Fast growing tumor cells require more oxygen than normal cells, and they are "oxygen starved" to death. Some normal cells in our body can be especially susceptible to the effects of radiation. The mucus membranes, or skin inside our mouth and throats, are tender to this lifesaving treatment. Salivary glands are especially sensitive as well. Therefore, people on radiation therapy for head and neck tumors frequently have side effects associated with the radiation itself or with the decreased blood flow. Radiation to other parts of the body does not have such an effect on oral tissues, unless it is given in combination with chemotherapy. Below find a list of the common side effects of radiation therapy and some palliative measures you can take to improve your lifestyle.

Dry Mouth, or xerostomia, is the most common side effect of radiation to the head or neck. Salivary gland cells are directly susceptible to radiation, and often shut down. The full function and flow of the salivary glands does generally not fully return.
    Dry mouth is made even worse by the continued use of tobacco products, alcohol in beverages and mouthwashes, caffiene, and many commonly used medications. Alcohol and tobacco use, frequently the cause of head and neck cancer, must stop immediately with the diagnosis of a tumor. Medications should be changed or adjusted by the prescribing doctor. Try decaf coffee and tea, and little sugar.
    Some medications, such as Salagen, or pilocarpine, can increase saliva flow. Ask your radiation oncologist. Chewing sugarless gum and sucking on diatetic (no sugar) citrus candies can also eke out the most saliva possible. Oral Balance, an over the counter gel, is a nice moisturizing coating for the inside of the mouth. Its manufacturer, Laclede Pharmaceuticals, has a nice variety of products for dry mouth patients, including mouthwashes and chewing gum. Most "saliva substitutes" have been, in our experience, less acceptible to our patients.
    We recommend acquiring the habit of drinking frequent sips of water to maintain the moisture inside the mouth. Our patients constantly carry bottled water, canteens, sports bottles, or other creative and fashionable vessels for their water supply. As will be explained below, one must not ever get in the habit of using sugared drinks, sports drinks, fruit juices, carbonated sodas, etc. for this purpose. Constant exposure to sugar or carbonic acid could spell disaster for the radiation patient. Water is the "solution".

Bad Cavities, or radiation caries, can be a consequence of decreased saliva flow, as described above. Saliva provides three protective functions for teeth: a) it physically washes the teeth to remove food particles, sugars, and starches; b) it contains antibodies and enzymes which kill or deter cavity forming bacteria; c) it serves as a chemical neutralizer, or buffer, for the acids produced by plaque bacteria. Unprotected people with dry mouth develop terrible cavities which start at the gumline and strangulate the teeth.
    Decades ago, patients were sent to the dentist to extract all of their teeth prior to radiation therapy. With current knowledge, this is necessary only for the most dentally unhealthy patients.
    Careful dental examination prior to your radiation therapy will see if any teeth need to be extracted. Any teeth with a hopeless, poor, or questionable prognosis must be extracted prior to radiation therapy. Fourteen to twenty one days of healing must pass prior to starting radiation therapy after an extraction, especially in the lower jaw.
    To prevent radiation cavities, every patient to recieve radiation therapy to the head or neck must give themselves daily fluoride treatments for the rest of their lives. This is usually done in custom applicators provided by a dentist. The fluoride is a prescription medication, and comes in flavors. Cavity-prone individuals may even need these treatments twice a day. The fluoride is kept in the mouth for four and one-half minutes, usually before bed and after other hygiene. Don't swallow any of it. Spit out all that you can, and don't put anything else in your mouth for at least thirty minutes.
    Some salivary function usually returns, but it will not be the same. Fluoride protection, and care with dietary sweets and acids, is forever.

Sterile Necrosis, technically called osteoradionecrosis or ORN, is a complication of radiation therapy that you do not want. Due to the deceased blood supply, especially in your lower jaw, should you ever need an extraction or surgery you are at risk for literally not healing. Such a problem can cause massive destruction of the jaw bone, and can even be fatal. This is the reason for discriminatory examination and aggressive treatment before radiation therapy. DO NOT LET A DENTIST EXTRACT A TOOTH WITHOUT CONSULTING YOUR RADIATION ONCOLOGIST, FOR THE REST OF YOUR LIFE AFTER RADIATION THERAPY.
    When indicated or absolutely necessary, extractions and other surgical treatments, including bone grafts and implants, can be accomplished with a special pre-treatment called hyperbaric oxygen, or HBO. This treatment increases the blood supply and allows for improved healing. We have been able to give patients a second chance with careful use of this treatment and judicious use of implants.
    The seriousness of this complication must be understood by your dentist. Second opinions or specialist consultations are recommended prior to acting on any invasive or traumatic treatment to the lower jaw.

Mucositis is a soreness or even blistering of the mucus membranes. It may be likened to having a bad sunburn inside your mouth and throat. Unchecked, it can prevent a person from eating and performing normal oral hygiene activities.
    Mucositis can be partly prevented by having your mouth in the healthiest possible condition prior to starting radiation therapy. Studies show a strong relation between gum health and resistance to mucositis. Schedule aggressive dental care prior to starting radiation therapy, and then maintain your mouth and teeth as clean as possible during your cancer treatment. Some patients feel that if they are not taking much food by mouth then there is no need for oral hygiene. This is wrong.
    Spicy foods, abrasive foods, and alcohol should be avoided so as not to aggravate the sore tissues. Drink lots of water to maintain your fluid balance and the moistness of your tissues.
    Your dentist or oncologist may prescribe viscous lidocaine (numbing agent) or some type of "Miracle Mix" (coating and numbing mixture) to assist in your comfort if your mucositis is especially bad.

Decreased Taste, or dysgeusis, is another side effect of radiation therapy to the head and neck. This is a direct result of radiation on the taste buds. It is usually one of the first side effects noticed, and thankfully recovery is usually close to 100%.
    Resolve yourself to the fact that for a few months your food will not taste as good; that you are eating to live. Do not overspice or oversweeten your foods and beverages.

Swallowing Problems, or dysphagia, is usually a minor problem in radiation therapy unless it is accompanied by chemotherapy. Mucositis can be the cause of swallowing pain, and is easily compensated for by taking smaller bites and accompanying each bite with a sip of water to wash it down. If too painful, a gargle with prescribed viscous lidocaine or benadryl elixir to numb the throat usually helps. Your radiation oncologist may provide you with a special cookbook to help with a few tough weeks. This effect usually doesn't last too long.

Muscle Spasm, or trismus, is a fairly uncommon side effect as well. Ocasionally muscles in the neck, throat, or jaw region will cramp up and go into spasm. This effect would tend to limit movement and/or cause pain. We have had a few patients with limited mouth opening which literally took years to return to adequate, but this is uncommon.
    We have seen a condition called Eagle Syndrome, in which a pre-existing bone anomaly in the neck is exacerbated by radiation therapy. This condition is easily diagnosed in a panorex x-ray. We are studying this phenomena in our practice and would appreciate any reports from patients or dentists regarding this.

Long Term Concerns Make sure that your dentist is aware and educated in the issues regarding radiation therapy. Not every dentist is aware of the potentially lethal issues surrounding treatment of patients long after radiation therapy. These special considerations are forever. If your dentist seems to take your concerns lightly, seek a second opinion prior to any surgical treatment or extractions, especially in the lower jaw. Your radiation oncologist should be able to help with any questions.

More information on chemotherapy

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