Being mindful of mouth health during treatment for breast cancer

Some treatments for breast cancer, such as chemotherapy and targeted therapy, may cause side effects in the mouth. Radiotherapy to the head and neck area may also cause mouth side effects.1,2,3

Potential mouth side effects include:1,4

  • Pain
  • Swelling and sores (which, together, are known as mucositis)
  • Cold sores
  • Infections
  • Dry mouth (also known as xerostoma)
  • Bleeding
  • Teeth problems, including decay
  • Changes in taste 

A rare, but serious, condition called osteonecrosis of the jaw is also a potential side effect of treatment. This may occur with treatments called bisphosphonates and antiresorptives, which may be used to prevent bone loss after breast cancer treatment. Osteonecrosis is where the bone in the jaw begins to die. It may show up as pain, swelling or redness in the gums, loose teeth, numbness or a heavy feeling in the jaw, or as being able to see bone in the mouth.5,6

Keeping an eye on oral health is important for everyone, but it is especially important during cancer treatment – so that you can lower your risk of experiencing mouth side effects and identify and tackle any issues quickly.1,3,7

Taking care of your mouth health at home 

Below we’ve shared some simple actions and recommendations to help you keep your mouth healthy before, during and after treatment for cancer. These include:5

Flossing
  • Floss at least once a day
  • Waxed floss may be easier to use and can be kinder to the gums                       
  • If flossing causes bleeding that does not stop after a few minutes, talk to your doctor 
Brushing
  • Use a small soft, rounded brush – it’s up to you whether you go for a manual or electric toothbrush
  • Rinse the toothbrush in hot water before use to soften it
  • Use fluoride-rich toothpaste and spit out the foam after brushing (don’t rinse it off)
  • Brush within 30 minutes after a meal and just before going to bed
  • Brush the place where the teeth and gums meet
  • Brush the tongue from back to front
  • Rinse the brush in warm water after use and let it air dry
  • Get a new toothbrush (or toothbrush head) when the bristles are not firm
Rinsing
  • Rinse with a gentle mouthwash (made up of half a teaspoon of salt and half a teaspoon of baking soda in a glass of warm water) several times a day
  • Rinse the mouth well to remove food and reduce plaque build-up
  • Spit out mouthwash after rinsing
  • Avoid mouthwashes with alcohol 
Wetting the mouth
  • Keep the mouth moist using water-based, artificial saliva or other mouth lubricants
  • Avoid glycerine or lemon swabs which can dry the mouth
  • Apply lubricant after every rinse
Lip care
  • Use only animal or vegetable-based oils, such as beeswax, coconut oil or lanolin
Removable dentures
  • Take out any overdentures and partial or full dentures before brushing your teeth
  • Brush and rinse dentures after meals and before going to bed
  • Take dentures out of the mouth for at least 8 hours each day and soak in mouthwash

Taking care of mouth health with your doctor and dentist  

Your doctor, dentist and wider healthcare team are there to help you keep your mouth healthy before, during and after treatment for cancer.1,3

Before starting breast cancer treatment3,5

  • Have a full mouth check, including x-rays, and go ahead with any required extractions/crowns and oral hygiene improvements that are recommended to you
  • Check and clean any dentures regularly, and adjust them if needed; treat the area if any bones are exposed

During breast cancer treatment5,8

  • Get regular dental check-ups, taking into account your cancer treatment dates
  • If invasive treatment is necessary, try and get it done within the first 3 months of cancer treatment
  • If you need mouth surgery, aim to have a check-up every 6-8 weeks until it is healed

After breast cancer treatment8

  • Keep getting regular dental check-ups (every month for the first 3 months, then every 3 months for the first year)
  • Be extra careful taking care of any dentures or implants you may have
  • If possible, try and avoid any invasive procedures, such as tooth extractions, for the first year
  • Keep good mouth hygiene, and see your dentist quickly if any issues arise

By being aware of potential side effects that may come with breast cancer treatment and knowing what to do if you notice any of these, you will be in a better place to relieve these side effects. Some side effects will be easier to manage than others. Remember, to speak to your doctor, dentist or medical team about any new or worsening side effects that you may have.1,3

References

  1. Breast Cancer Network Australia. Mouth problems with breast cancer treatment. Available from: https://www.bcna.org.au/resources/side-effects/a-to-z-of-side-effects/mouth-problems/ [Accessed June 2025].
  2. Sarah Cannon Cancer Network. Side effects of breast cancer. Available from: https://sarahcannon.com/for-patients/learn-about-cancer/breast-cancer/side-effects.dot [Accessed June 2025].
  3. Cancer Research UK. Mouth problems and cancer treatment. Available from: https://www.cancerresearchuk.org/about-cancer/coping/physically/mouth-problems/problems-and-treatments [Accessed June 2025].
  4. National Cancer Institute. Oral complications of cancer therapies – patient version. Available from: https://www.cancer.gov/about-cancer/treatment/side-effects/mouth-throat/oral-complications-pdq [Accessed June 2025].
  5. González AF, et al. Beyond cancer treatment: dermo-aesthetic and other wellness recommendations for breast cancer patients. Clin Transl Oncol 2025 Mar;27(3):909-934.
  6. BreastCancer.Org. Osteonecrosis of the jaw. Available from: https://www.breastcancer.org/treatment-side-effects/osteonecrosis [Accessed June 2025].
  7. NHS England. World Oral Health Day Blog. Available from: https://www.england.nhs.uk/north-west/gmec-clinical-networks/about-us/news/wohd23/  [Accessed June 2025].
  8. Poulopoulos A, et al. Chemotherapy: oral side effects and dental interventions. A review of the literature. Stomatological Dis Sci 2017;1:35-49.