Did you know that the side effects of some breast cancer treatments, such as hormonal therapy, chemotherapy, and bone drugs, can affect your teeth, gums, and mouth? Your dental health is an important part of your overall physical health and quality of life.

Read on to learn how various breast cancer treatments can affect your oral health.

1. Gum Problems

You might experience gum disease (also called periodontitis or gingivitis) if you’re receiving breast cancer treatment with hormonal therapy or chemotherapy. Your gums are the soft tissues that surround your teeth.

Common symptoms of gum disease include:

• Swollen gums
• Gums that look discolored (bright red, dark red, or purple)
• Tender or painful gums
• Gums that bleed easily during brushing or flossing
• Bad breath
• Loose teeth
• Gums that recede (pull away from your teeth)
• Changes in your bite

Treatment with hormone therapy and chemotherapy can make you more likely to develop tooth pain or sensitivity.

You may take hormonal therapy if you have hormone receptor-positive breast cancer. Hormonal therapy can affect your gums by blocking the positive effect of sex hormones, such as estrogen, which are involved in gum health and gum tissue growth.

Examples of antiestrogen hormone therapy include:

• Selective estrogen receptor modulators, such as tamoxifen (Soltamox)
• Aromatase inhibitors, such as anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara)

Chemotherapy side effects can also raise your risk of gum disease. Some chemotherapy drugs can increase gum bleeding by affecting how your blood clots. A MyBCTeam member who’d received chemotherapy commented, “I am scared to go to the dentist because my gums are so sensitive!”

2. Tooth Pain and Sensitivity

Tooth pain and sensitivity can happen when dentin (a tooth’s inner layer) becomes exposed. Usually, dentin is covered by enamel or by your gums. If your teeth are sensitive, you may feel a sudden, sharp pain when you eat or drink something that’s too cold, hot, sweet, or sour.

You also might experience tooth pain if you have:

• A cavity
• Tooth damage
• Gum disease
• An infection

Treatment with hormone therapy and chemotherapy can make you more likely to develop tooth pain or sensitivity. Specific side effects that may contribute to sensitivity and pain include dry mouth, gum disease, and increased risk of infection.

3. Mouth Sores

Mouth sores — also known as oral lesions, mucositis, or stomatitis — are painful oral lesions that may look like cuts or ulcers on your inner cheek, tongue, or gums.

Tamoxifen may be involved in the development of mouth sores. In one small study, about 24 percent of breast cancer survivors had at least one oral lesion. The researchers reported that using tamoxifen for a longer time, having dry mouth, and previously receiving radiation therapy were linked with oral lesions.

According to the National Cancer Institute, mouth sores are among the most common side effects of chemotherapy. If you have severe oral sores, your cancer care team might suggest temporarily stopping or lowering your chemotherapy dose to allow them to heal, which may affect your prognosis (outlook).

Several chemotherapies and targeted therapies used to treat breast cancer are likely to cause mouth sores, such as:

• 5-fluorouracil (5-FU)
• Carboplatin
• Doxorubicin
• Everolimus (Afinitor)
• Exemestane (Aromasin)
• Paclitaxel protein-bound (Abraxane)

4. Dry Mouth

If your salivary glands don’t make enough saliva (spit), you may develop xerostomia (dry mouth). Several medical conditions and medications, including breast cancer treatments, can cause dry mouth. Symptoms include:

• Trouble eating and swallowing
• Difficulty speaking
• Bad breath
• Sore throat
• Mouth pain

During breast cancer therapy, these uncomfortable symptoms can affect your quality of life and lead to more serious complications, such as tooth decay and gum disease.

Make your dentist part of your cancer care team. Identifying dental side effects early can help keep them from becoming severe.

Low estrogen levels can decrease saliva production, resulting in dry mouth. If you take tamoxifen or other hormonal therapies that block estrogen, your salivary glands may make less spit.

Chemotherapy can cause dry mouth by directly damaging salivary glands. One 2020 study of 27 women undergoing chemotherapy for breast cancer showed that dry mouth was common, no matter which regimen the participants used. For most people, this side effect is temporary and resolves after two to three months.

5. Infections

You might be more prone to an infection in your mouth during breast cancer treatment. Chemotherapy can weaken your immune system by decreasing your body’s number of infection-fighting white blood cells. Other chemotherapy side effects, such as oral lesions and dry mouth, may raise your risk of infection even more.

Common oral infections during chemotherapy include:

• Bacterial infections
• Candidiasis (oral thrush)
• Herpes virus

An infection in your mouth may feel or look similar to other side effects of gum disease or mouth sores. Additional oral symptoms may include:

• Burning pain
• Taste changes
• White, “cottage cheese-like” lesions on your tongue or cheek or the roof of your mouth
• Fluid-filled blisters

6. Tooth Loss

You may be more likely to lose teeth if you take tamoxifen or other hormonal therapies for breast cancer treatment. Tooth loss could be the result of hormonal therapy blocking estrogen’s positive effects on dental health.

You may be more likely to lose teeth if you take tamoxifen or other hormonal therapies for breast cancer treatment.

A 2024 study evaluating 200 women with breast cancer compared those treated with tamoxifen to those who did not receive the medication. The study authors found that the use of tamoxifen for more than one year was associated with greater tooth loss. In another study of 140 breast cancer survivors taking tamoxifen, only three participants didn’t lose any teeth during the study period. Researchers found losing 12 or more teeth was linked with certain factors, including:

• Longer tamoxifen use (more than one year)
• Age older than 65
• Less use of dental services
• Dry mouth
• Fewer cavities

7. Jaw Pain

Jaw pain can be a rare but serious side effect of some bone drugs. These medications may lead bone tissue in your jaw to break down, causing a condition called osteonecrosis of the jaw (ONJ). If you have ONJ, you may have jaw pain and other symptoms, such as:

• Infection
• Loose teeth
• Jawbone poking through gums

Bone drugs that can cause ONJ include:

• Bisphosphonates, such as alendronate (Binosto, Fosamax) and zoledronic acid (Reclast, Zometa)
• Denosumab (Prolia, Xgeva)

Your doctor might prescribe a bone drug if you have osteoporosis (loss of bone density) or pain from bone metastases (cancer that has spread to bones). Breast cancer survivors have a 68 percent higher risk of osteoporosis compared to women without cancer, according to a study in the journal Breast Cancer Research.

Although ONJ is a serious side effect, it’s rare. The condition affects about 2 percent of people with cancer who take a bone drug. Preventing osteoporosis by taking a bone drug can benefit your oral health because osteoporosis is a risk factor for both gum disease and tooth loss.

Preventing Dental Side Effects

The National Cancer Institute recommends that dental professionals, such as dentists and dental hygienists, be considered part of your cancer care team. If possible, visit a dentist about four weeks before you start treatment. That way, you can treat any current dental problems or infections and give your mouth time to heal before you start your cancer regimen.

Identifying dental side effects early can help keep them from becoming severe. There aren’t any guidelines about how often you should visit the dentist before, during, or after treatment, so talk with your cancer care team about how often you should follow up with your dentist.

A MyBCTeam member shared, “I went to the dentist right before and right after my chemo. She is helping a lot and is pretty sure she can save my teeth. I am more afraid of losing my teeth than the dentist!”

Oral Hygiene Tips

Practicing good oral hygiene before, during, and after breast cancer treatment can help prevent dental side effects from medications. Healthy dental habits include:

• Brushing your teeth twice a day with a soft-bristled toothbrush
• Brushing your tongue
• Using toothpaste with fluoride
• Flossing daily
• Avoiding smoking and vaping
• Rinsing with antibacterial mouthwash every day
• Visiting the dentist regularly

You may also want to avoid foods that can irritate your mouth, such as those that have a rough texture or are spicy, sour, or acidic. It might also help to avoid drinks containing alcohol.

If you have any questions or concerns about protecting your dental health, be sure to discuss them with your healthcare team. They’ll help you figure out the best ways to manage dental side effects — and any other side effects — related to your cancer treatment.

Talk With Others Who Understand

MyBCTeam is the social network for people with breast cancer and their loved ones. On MyBCTeam, more than 76,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you experienced any dental side effects of breast cancer treatment? How did they affect your daily life? Share your thoughts in the comments below, or start a conversation by posting on your Activities ​​page.