Radiation & Chemotherapy – the Effects on Your Mouth

Written By:

Matthew Norman, DDS and Michelle Phillips, RDH


With the prevalence of cancer becoming more widespread, it is important to be aware of and know how to manage side effects that cancer treatment can cause in your mouth.  Radiation and chemotherapy are two different types of treatments for cancer, but can have similar effects in the oral cavity.  Radiation therapy and chemotherapy can cause cavities, mouth sores, oral infections, dry mouth, bleeding gums, and mouth pain/soreness.  Most symptoms are acute, meaning that they begin shortly after treatment begins and go away shortly after treatment ends.  The symptoms can last indefinitely when there is direct treatment to the head and neck.

Cancer cells are generally the fastest growing cells in the body and these rapidly dividing cells attack the healthy cells.  Chemotherapy works by killing all the rapidly growing cells in your body, while killing healthy cells at the same time.  Radiation therapy is generally more site-specific, targeting the cancerous lesion but healthy cells are affected too.  The cells lining the mouth are fast-growing, making it more likely for these cells to be damaged by the treatment. 

Dry mouth can arise from both radiation therapy and chemotherapy treatments.  Dry mouth is typically the root to the other side effects associated with cancer treatments.  When the gum tissue is dehydrated and very dry to the touch, any trauma (from a toothbrush, floss, or food) can not only cause your gums to bleed, but this trauma can also cause a mouth sores.  Because your immune system is compromised while going through radiation and chemotherapy treatments, these areas heal at a slower rate.  When the tissues in your mouth are really dry, it may even be painful to eat and swallow, which can create nutritional deficiencies.  Your taste perception can also be altered by these treatments, which can compound the problem of malnourishment or dehydration.  Dry mouth is a major instigator of rampant dental caries (or decay), especially on root surfaces of teeth.  Saliva is very important in protecting our teeth from tooth decay—there are certain enzymes present in our saliva to defend against the formation of dental caries.  Saliva helps to wash the teeth clean to remove the plaque or food debris that may be present.

Maintaining a healthy mouth is very important while going through radiation therapy and chemotherapy.  There are several things that can be done to help keep your mouth healthy.  To help keep the mouth moistened, you can suck on ice chips, sip water frequently, chew sugar-free candy and gum, or use saliva substitutes.  You also want to be sure to keep your teeth and mouth as clean as possible.  Using an extra-soft toothbrush and gentle flossing will be kinder to your gums.  Try to keep away from foods with sharp edges, like chips, to avoid any scratching or trauma to the gum tissue.  Additionally, hot and spicy foods may be uncomfortable if you’re suffering from dry mouth, as it may cause a burning sensation.

Fluoride exposure is especially important when undergoing cancer treatments.  Fluoride helps to strengthen the teeth and prevent cavities, especially when a dry mouth is present.  Fluoride-containing toothpaste and mouthrinses are critical throughout your treatment.  Fluoride varnish treatments should be applied at your regular dental hygiene appointments.  If dental decay becomes a problem during your treatment, your Dentist may recommend making custom fluoride trays to allow for frequent fluoride treatments at home.  If mouth sores become a problem, your Dentist can prescribe a rinse to help with the discomfort.  This rinse contains a numbing agent (for pain), and an anti-fungal/anti-bacteria component to speed up healing.

It is extremely important to be examined by your Dentist to ensure your mouth is in a healthy condition before you begin your cancer treatment.  As you undergo your cancer treatments, be aware of your mouth and the condition it is in.  Keep in mind these tips which will help you to manage the possible symptoms that may arise while going through radiation therapy and chemotherapy.  Continue your hygiene appointments with your Dental Office and don’t hesitate to call if you have any problems.