Chemo and Radiation Therapy and How It Relates to Oral and Dental Health Including Dry Mouth

According to the 2014 World Cancer Report About 14.1 million new cancer cases occur a year. The most common types of cancer in males are lung, prostate, colorectal and stomach cancer. In females the most common are breast, colorectal, long and cervical cancer. (1) Two common ways of treating cancer are chemo and radiation therapy. Both can have significant effects on the oral and dental health. We explore these factors and ways of managing them in this article.


Chemotherapy is a common treatment method for cancer treatment which involves cytotoxic and anti-neoplastic drugs. These drugs kill cells that divide rapidly, such as cancer cells.


Radiation therapy is intended to target cancer cells with ionized radiation. Tissues of the oral cavity or salivary glands can be permanently damaged with this form of treatment, which can cause a permanent decrease in salivary flow (dry mouth).  


What are the side-affects to radiation and chemotherapy?


According to Dental Management of Medically Patient (2), Chemo and radiation therapy can cause, hair loss breakdown of tissues, damage to the bone marrow which can result in infection, bleeding and anemia, stomach problems, and weight loss. It can also affect the heart and lungs. Patients receiving chemotherapy can experience bleeding, ulcerations, dry mouth, anemia, infections, neurotoxicity.


How does chemo and radiation therapy affect our teeth and oral cavity?

Dry mouth and lack of saliva can cause cavities and gum disease which can cause tooth infections and tooth loss. Read here about gum disease. Chemo and radiation therapy can lead to oral ulceration and increase the risk of bacterial, viral and fungal infections. Disorders of white blood cells. Undetected leukemia patients may experience increased bleeding, difficulty healing, can be prone to surgical infections


How to approach oral health before, during, and after radiation and or chemotherapy?

Before starting treatment

After learning of the need to have cancer therapy it is important to see a dentist for pre-treatment evaluation and planning. AT LEAST THREE weeks prior to start of chemotherapy is recommended.

During this evaluation

  • It is established what kind of cancer is being treated (whether it involves the oral cavity). Though some cancers can affect the oral cavity indirectly through chemotherapy and or immunosuppression.
  • Medical history is reviewed, history of cancer in the family. Patient is asked whether they had noticed lumps/bumps, any pain on the body, fever, weight loss, bleeding tendencies etc.
  • Head and neck and intraoral soft tissue examination including lymph nodes is performed.
  • Lesions such as ulcers that do not to heal after 14 days are considered for evaluation and or biopsy.
  • Oral hygiene instructions are reviewed: brushing 2 times per day, flossing 1 time per day. Discuss the different methods to manage dry mouth including prescription medication such as Pilocarpine. 
  • Diet discussed such as non- cariogenic (low sugar), soft foods. Avoid tobacco, alcohol, spicy, sour foods.
  • In the dental office:
  • Plaque/calculus removal through cleanings and or scaling;
  • Fluoride treatment.
  • Blood test results should be reviewed.
  • Cavities and infection should be eliminated with more acute needs being done first.  
  • If infection is detected root canal therapy or extraction is recommended before beginning of chemotherapy.
  • If there is advanced gum disease or if oral hygiene is not good extraction might be a better option instead of trying to save the teeth.
  • Extractions are usually recommended to be done 10-14 days (3 weeks preferable) to start of chemotherapy.
  • If patients are wearing dentures, it is important to prevent injury to tissues by adjusting not-well-fitting dentures.
  • If patient becomes neutropenic (low level of white blood cells) some dental treatment may not be recommended and patient might require prophylactic antibiotics.
  • With Radiation therapy the dentist should discuss with radiation oncologist the option of using led-lined stents and beam spearing procedures to protect salivary glands.

 During Radiation and Chemotherapy

 When undergoing chemotherapy there are many side effects we need to be aware of and try to prevent/manage 


  • Mucositis (painful inflammation and ulceration of tissues in the oral cavity and digestive tract. It can also occur close to metallic restorations. 40% of patients undergoing chemotherapy experience this complication and is more likely to occur in younger patients (28). Common symptoms include oral burn, ulcerations (due to infection by viruses, bacteria, fungus), loss of taste, difficulty in eating, dry mouth.

 Managing mucositis:

  • Nonalcoholic mouth rinse,
  • Topical anesthetic (such as Benadryl),
  • Systemic pain medications (59),
  • Antibacterial rinses such as Chlorhexidine,
  • Anti-inflammatory agents such as topical steroids,
  • Hydration,
  • Diet (soft foods, protein, vitamin supplementation),
  • Oral lubricants and lip balms containing a water base, a beeswax base or vegetable oil base.
  • Humidifers
  • Removal of sharp edges and restorations
  • Dentures should not be worn until acute phase of mucositis is resolved.
    • Dentures are to be cleaned and soaked with antimicrobial solution recommended by your dentist


  • Radiation cavities. Patients undergoing radiation/chemotherapy ar at a much higher risk for cavities. Some of the ways to tey to prevent them include:
    • Daily application of fluoride,
    • Use of trays of extra strength fluoride toothpaste.
    • Frequent dental recall.
    • Rigorous oral hygiene
    • Restoration of early cavities.


Read more: What Causes Dry Mouth? Dry Mouth Symptoms and Home Remedies


  • Secondary Infections. With chemo and radiation therapy our oral cavity becomes more vulnerable to infections, especially candida albicans (candidiasis, a form of a fungus). Read here about dry mouth and candidiasis. 
    • The most common form is pseudomembranous candidiasis that produces white plaque which is usually can be wiped off.
    • Less common is the erythematous, atrophic form which looks like a red patch that has a burning sensation.
    • Candidiasis is usually managed with topical anti-fungals such as Nystatin and Clotrimazole.
    • Sometimes prophylactic use of prophylactic antifungals is recommended.
    • For systemic treatment Ketoconazole (Nizoral), fluconazole (Diflucan) or itraconazole (Sporanox) may be indicated.
    • When our immune systems are weakened, the bacterial balance in the mouth changes. The type of bacteria that inhabits our oral cavity are now similar to the type that lives in our respiratory and GI tract (gram negative bacteria) They can cause increased ulcerations.


  • Increased bleeding. With chemotherapy we can have an increased rate of bleeding.
    • It is important to avoid rigorous brushing and to use softer toothbrush or gauze wrapped around a finger dampened in warm water or antibacterial solution.
    • Do not use toothpicks, water irrigating appliances or dental floss.
    • To control bleeding apply pressure with a wet gauze.
    • If these local measures fail, medical help should be obtained.


  • Neural and chemosensory changes – Chemo/radiation therapy can cause diminished/altered taste due to damage of the taste buds. One can experience bitter taste, unpleasant odors and have conditioned aversions to foods which one never had before. Speak to your doctor about taking Zinc supplements (220mg 2 times per day) to help. (3), However there currently is no effective cure loss of taste.
    • Some chemotherapy medications can be damaging to our nerves (neurotoxic). Usually the effects occur in nerves that are further from the central nerves (peripheral nerves). Tooth pain can also occur, and it may seem like a tooth infection even if there is none. Usually occurs in back teeth and can occur on both sides.
  • Neutropenia (low white blood cells) which weakens our body’s ability to protect itself. When patients have poor oral hygiene at the same time, they may experience gum disease, which can progress to damage of toot-supporting structures (periodontitis). Periodontal and antimicrobial therapy may be needed.
  • Some of the chemotherapy medications can have side effects and can cause overgrowth of gums (gums become larger and can cover more teeth than before).
  • Nausea and vomiting. Vomit is very acidic and can cause tooth erosion. Very important to brush teeth after vomiting.

Radiation therapy can also cause

  • Tooth sensitivity. Fluoride application, Sensodyne toothpaste had been found to help.
  • Trauma to oral mucosa which may make it difficult to wear dentures, may be indicated to stop wearing dentures for 6 months after therapy.
  • Muscular dysfunction – limited opening of jaw muscles. Stretching exercises and application of warm moist heat is recommended.
  • Osteoradionecrosis – happens that exposed bone (jaw bone that is no longer covered by the gums) does not heal. Usually is present for 6 months after radiation. Be careful with having with surgery such as tooth extractions and implants. If surgery is absolutely needed some doctors may recommend possible need for hyperbaric oxygen therapy.


After treatment

After chemotherapy is completed, the dentist should consult with the oncologist, to make sure recommended precautions are being managed.  


Patient should be placed on oral recall program (every 1-3 months for the first 2 years and at lease 3-6 months after that.


The long-term complications include

  • Dry mouth, cavities, gum disease, tooth infections.
  • Loss of taste
  • Altered bone
  • Tooth sensitivity due to decreased secretion of saliva and lowered pH (more acidity).

Steps we could take:


Read moreWhat Causes Dry Mouth? Dry Mouth Symptoms and Home Remedies




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1) World Cancer Report 2014. World Health Organization. 2014. Chapter 1.1

2) Little, J. Falace, D. Miller, C. Rhodus, N. “Dental Management of Medically Compromised Patient” Seventh Edition

3) Silverman S Jr Oral Cancer, 4th Hmailton, Ontario BC Decker Inc. 1998.

1 comment

  • Had the necrosis of the jaw bone. Had the mucocitis, Did the hyperbaric chamber for 60 sessions. Had a feeding tube for 6 months due to radiation burn of the throat…when I vomited after chemo. I had neck cancer, surgery, chemo, radiation. Teeth are now taking a beating…15 years after the cure. I’m glad to be alive. I thought 5 years was good. This is great. But…it’s still a heavy load to carry. Food doesn’t taste. Chewing without saliva is tough. A lot of gagging and choking. At 72…I’m hanging in there. Now…as if life isn’t tough enough…I have IBS-D. Had it before…starting at maybe age 24…or earlier. It’s not easy. I’m in the process of my 6th root canal. Expensive…you bet.

    John R Day

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