Dental Health and Colorectal Cancer


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Your teeth and gums may be the last thing on your mind when you’re facing colorectal cancer, but it’s important to not neglect this important aspect of your health. If you’re going to receive chemotherapy, you’ll want to pay special attention to your mouth.  

Before chemo

Seeing your dentist before you start chemo can help protect your oral health. Chemo can upset the balance of bacteria in your mouth and cause tooth decay, infections, or mouth sores. Having a dental checkup before you begin chemo may help you head off teeth and gum problems, and your dentist may also have tips to prevent mouth sores and dry mouth. See your dentist as a part of your medical team. 

Fact or Crap: I don’t need to see a dentist until I’m finished with chemo. 


The National Institutes of Health recommends seeing a dentist one month before starting chemotherapy. If your dentist’s office is unable to get you in immediately, call and let them know why it’s urgent, and ask to be contacted if they have any cancellations. 

During chemo: 5 mouth issues you may experience 

Chemotherapy can affect your oral health because it delivers toxins to normal cells. Because of the rapid rate of cell turnover in your mouth, you may experience many side effects in your mouth during and after treatment.  

Here are 5 mouth issues patients experience during chemo treatment: 

  1. Gingivitis: Since chemo weakens your immune system, it’s easier for bacteria to cause gum infections. Red, swollen, and bleeding gums can be a sign.  
  1. Mouth sores (mucositis): These painful sores can develop on your gums, tongue, and other areas of your mouth. Mouth sores can make it incredibly difficult for you to eat and maintain oral hygiene. Your doctor and/or dentist may be able to recommend mouthwashes if mouth sores become a problem for you. 
  1. Dry mouth: Because chemotherapy may reduce your saliva output, you may develop dry mouth (xerostomia). Saliva keeps your mouth clean and protects your gums. When you don’t have enough saliva, your gums can become irritated and at risk for infection. 
  1. Increased mouth sensitivity: Some chemo drugs can make your gums more sensitive and likely to bleed. Even gentle brushing or flossing can cause pain and gum bleeding. 
  1. Delayed healing: If you undergo dental procedures during or after chemo, it may take longer for your gums to heal. 

Consider this: Nutrition is a key part of maintaining your overall health while on chemotherapy. If you have oral health issues, it can become difficult to eat.  

Oral health in survivorship 

Dental health is also important once chemotherapy ends. Chemotherapy can affect the health of your teeth and mouth, and regular checkups can catch concerns right away—when they are easier to treat. Some patients’ dental side effects go away once chemotherapy ends and others struggle with them for longer periods of time. It’s important to stay on top of dental visits so you and your dentist can monitor issues like:  

  • Increased risk of cavities 
  • Susceptibility to gum disease 
  • Tooth discoloration  
  • Sensitivity or pain  
  • Change in taste and appetite 

Be kind to yourself if you experience dental health issues. Regular dental visits are essential for staying on top of oral health and addressing problems before they begin. Make sure your dentist knows which chemotherapy treatments you received and any additional medications you were prescribed.  

Your dental insurance plan will differ from your medical plan but utilize as many benefits as you're offered. Dental benefits typically include checkups every six months, X-rays of your teeth, and coverage for fillings and other procedures.  

Ask the expert: What does good oral hygiene look like for cancer patients? 

Sylvia Jernigan, DDS; John Highsmith DDS; Clyde, North Carolina  

People fighting colorectal cancer may develop more cavities because of tooth decay or gum disease due to changes in their mouth while they’re undergoing chemotherapy.  
It’s easy to understand that during active chemo, people may not spend as much time brushing and flossing their teeth or rinsing out their mouths, since they don’t feel well and may not have the energy.  

But getting rid of plaque is one of the best ways patients can maintain their dental health because bacteria have toxins and create acidic environments that make teeth softer and dissolve the tooth structure. I would encourage patients to do as many of the items below as they can to maintain good oral hygiene during and after chemotherapy:  

  1. Brush your teeth with a soft-bristle toothbrush gently after every meal and snacks.  
    • If you can’t brush, try to rinse with water. 
  2. Floss gently to remove plaque and debris. 
    • The rubbing motion helps to loosen debris. 
  3. Stimulate saliva (with sugar-free gums or candies) and drink plenty of water. 
    • Avoid candy and gum that contains sugar. Choose something with Xylitol if you can.   
  4. Keep the pH balance in your mouth up. 
    • Your saliva pH level goes down when you eat and drink. It returns to normal about 30 minutes later. Try drinks that have higher pH levels. 
  5. If you vomit, rinse your mouth out, don’t brush your teeth. 
    • Your teeth are softer and more likely to be damaged. Be sure to rinse your mouth out, but don’t brush your teeth. 
  6. Maintain regular dental checkups and cleanings. 
    • Checkups may help prevent larger oral health issues in the future. 
Oral Chemotherapy and Colorectal Cancer

Shopping list for your dental health

Dr. Jernigan and Laura Inman, dental hygienist, recommend the following items for patients receiving cancer treatment: 

Inman stresses resisting the urge to pop a peppermint or lozenge that isn’t sugar free. “If it’s not sugar-free, you’re looking at an instant cavity. Xylitol is a sweetener that keeps plaque away from your teeth’s surface. It can also reduce gum inflammation.” 

Patient pro tips 

"I did know I would experience dry mouth and used Biotene® to fight against it. As for the cavities, I did not go to the dentist during treatment. I was one more medical-ish appointment that I didn’t want to endure with everything else. It was a regular visit after that the cavities were discovered.” –Michael Holtz, stage III survivor 

Michael Holtz Dental Health
Pam Allen Dental Health Blog

"While I was receiving chemo, I developed sores in the roof of my mouth, which made it very difficult for me to eat or take my meds. My oncologist prescribed magic mouthwash, a solution mixed together by the pharmacist.” –Pam Allen, stage III survivor

“The biggest thing that has helped me during treatment is the plaque tablets. During treatment week, I’m tired. I’m nauseous. I feel so bad, and I don’t even want to get out of bed. It’s really hard for me to spend a lot of time brushing my teeth. So, I can use the plaque tablets to pinpoint where I need to focus better, and this has helped tremendously.” –JJ Singleton, stage IV survivor 

JJ Singleton Dental Health blog

Your Guide in the Fight 

Check out our additional resources to help you navigate chemotherapy and other side effects: 

Medical input and review 

Sylvia Jernigan, DDS; John Highsmith DDS; Clyde, North Carolina


The information and services provided by Fight Colorectal Cancer are for general information purposes only. The information and services are not intended to be substitutes for professional medical advice, diagnoses or treatment. If you are ill, or suspect that you are ill, see a doctor immediately. In the event of an emergency, call 911 or go to the nearest emergency room. Fight Colorectal Cancer never recommends or endorses any specific physicians, products or treatments for any condition. 

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