Dental problems

Last medical review:

Dental problems can develop during and after some types of cancer treatment. Sometimes dental problems happen as a late effect of treatments for cancer during childhood. Children younger than 8 years of age during treatment have a higher risk of having dental problems because the teeth aren't fully developed yet.

How the teeth and jaws work

Baby teeth start to come in between 6 and 12 months of age and are completed by the time you are 3 years old. At age 6 or 7, the first adult (permanent) teeth begin to come in. Calcification of the adult teeth begins in the first year that they come in. The enamel, which protects adult teeth, is complete at 8 years of age. The roots of the teeth are complete by 16 years of age.

The mouth, including the teeth and jaws, is the first part of the digestion process. In the mouth, food is mixed with saliva and then the teeth chew it. This process starts breaking down the food before it is swallowed.

The upper jaw bones, or maxilla bones, are the largest bones in the face. They support the upper teeth. The lower jaw bone, or mandible, supports the lower teeth. The upper and lower jaws move to open and close your mouth so you can chew food and speak. Muscles control the movement of the jaw bones.

Diagram of the teeth and jaws
Diagram of the teeth and jaws


The following cancer treatments can cause dental problems.

Radiation therapy

Radiation therapy to the mouth, head or neck can affect the lining of the mouth and the salivary glands, which are very sensitive to radiation. This can cause dry mouth, tooth decay and other dental problems. The higher the dose of radiation, the greater the risk of dental problems.

If chemotherapy drugs are given along with radiation therapy, there is a greater risk for dental problems.

Total body irradiation (TBI) can affect the teeth. In children, the teeth may not develop normally. In adults, TBI may cause dental problems.


Chemotherapy can affect the lining of the mouth and the salivary glands, which can cause dry mouth, tooth decay and other dental problems. Children who are younger than 8 years of age or whose adult teeth haven't developed yet can also have problems with tooth development after chemotherapy. Dental problems are more common when higher doses of chemotherapy are given.

Stem cell transplant

Different aspects of a stem cell transplant can lead to dental problems. Drugs that are given to make sure that the body doesn't reject the new stem cells, such as azathioprine (Imuran), increase the risk for dental problems. Chemotherapy drugs commonly used in preparing for a stem cell transplant, such as busulfan and cyclophosphamide, can also affect the teeth and how they develop. People who develop chronic graft-versus-host disease (GVHD) from a stem cell transplant may also develop dental problems, such as cavities and gum disease.

Types of dental problems

Different types of dental problems can develop after chemotherapy, radiation therapy or a stem cell transplant, including:

  • increased risk of cavities
  • shortening or thinning of teeth roots
  • absence of teeth or roots
  • white or discoloured patches on the teeth
  • grooves or pits in the teeth
  • easy staining of the teeth
  • taste changes

Radiation therapy to the mouth or jaw area can also cause:

  • dry mouth due to lowered saliva production
  • greater risk that the teeth will be sensitive to hot and cold
  • trismus (difficulty opening the jaw)
  • temporomandibular joint (TMJ) dysfunction, which causes pain in front of the ears
  • hardening of the jaw muscles (called fibrosis)
  • gum disease
  • osteoradionecrosis (bone death caused by radiation therapy)
  • oral cancer

Children who are treated before their teeth are fully developed may also have the following problems with the development of the teeth and jaw:

  • small teeth
  • permanent teeth that come in later than usual (called delayed eruption)
  • early loss of teeth or baby teeth that don't fall out
  • overbite or underbite
  • abnormal growth of bones in the face and neck


Symptoms can vary depending on the type of dental problem and can include:

  • red, tender or puffy gums
  • gums that bleed easily
  • tooth pain or sensitivity
  • a sore in the mouth that doesn't heal or bleeds easily
  • a change in the colour of the tissues in the mouth
  • a lump, thickening or rough spot in the mouth
  • soreness or numbness in the mouth or on the lips
If symptoms get worse or don't go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.


You may see a dentist, an orthodontist or an oral surgeon to check for dental problems. They may do the following tests:

  • examining the teeth and mouth
  • x-rays to assess tooth and jaw development
  • a panorex x-ray (an x-ray of the upper and lower jaw) to show the health of the teeth, roots and supporting bones

Managing dental problems

Treatments will depend on the types of dental problems that develop and can include:

  • caps or crowns for adult teeth that are unhealthy or don't develop normally
  • reconstructive surgery to correct poor bone growth of the face or jaw
  • stretching exercises for the jaw to improve your ability to open your mouth
  • bonding (a thin coating of plastic material) applied to the surface of the teeth to improve the appearance of crooked or small teeth

If you had high doses of radiation to the face or mouth, your dentist will talk to you and the radiation oncologist about the risk of osteoradionecrosis before doing any dental surgery.

Preventing dental problems

Taking care of your teeth and gums is always important. Dental care is very important if you received radiation therapy or chemotherapy, especially if at a young age.

Talk to your dentist about how you can keep your teeth and mouth as healthy as possible. Your dentist may recommend the following:

  • Have regular follow-ups with your dentist.
  • Brush your teeth at least 2 times each day. Floss your teeth 1 to 2 times each day. Use a fluoride rinse or gel each day.
  • Use antibacterial, alcohol-free fluoride rinses.
  • Apply fluoride as directed by your dentist.
  • Drink liquids often.
  • Use artificial saliva.
  • Limit sweets and carbohydrate-rich foods.
  • Don't use tobacco products.
  • Limit the amount of alcohol you drink.


All people who are treated for cancer need regular follow-up. The healthcare team will develop a follow-up plan based on the type of cancer, how it was treated and your needs.

People who receive radiation therapy to the head or neck area or a stem cell transplant should get dental checkups every 6 months. Make sure you tell your dentist about all the treatments you received.

Follow-up may include the following:

  • examining the teeth and gums
  • dental x-rays
  • examining the mouth for signs of oral cavity cancer

Expert review and references

  • Mary Stuart, FNP, MSN, MN

Medical disclaimer

The information that the Canadian Cancer Society provides does not replace your relationship with your doctor. The information is for your general use, so be sure to talk to a qualified healthcare professional before making medical decisions or if you have questions about your health.

We do our best to make sure that the information we provide is accurate and reliable but cannot guarantee that it is error-free or complete.

The Canadian Cancer Society is not responsible for the quality of the information or services provided by other organizations and mentioned on, nor do we endorse any service, product, treatment or therapy.

1-888-939-3333 | | © 2024 Canadian Cancer Society