About 13 percent of cancers worldwide are caused by infections, including the human papillomavirus, H. pylori, hepatitis B and C, and the Epstein-Barr virus.1 The mouth is one of the most overlooked places for chronic infection. An infection at the tip of a tooth root or in a hollow area of the jawbone can smolder for years without pain, constantly releasing bacteria and inflammatory signals into the bloodstream. Biological dentists have long held that these hidden infections burden the immune system, and research now shows that some mouth bacteria travel to tumors and help them grow. This article explains what the research shows and how dental care fits into cancer care.
Dr. Silver, MD’s Own Story
Dr. Silver, MD, had lymphoma in his neck and across the center of his chest. Among the factors he names as part of the cause are infected root canals, cavitations in his jaw and mercury amalgam fillings. As part of his recovery, his infected root-canal teeth were removed, his amalgam fillings were taken out, the cavitations in his jaw were cleaned, and ozone was placed into his jaw. Read his story.
Mouth Bacteria Found Inside Tumors
Fusobacterium nucleatum. This common mouth bacterium is found inside many colorectal cancers. Researchers in Shanghai showed that it helps colon cancer cells survive oxaliplatin and fluorouracil chemotherapy.2 A 2024 study in Nature found that one particular type of this bacterium dominates colorectal tumors.3 See our article on colon cancer.
Porphyromonas gingivalis. In a large study that collected mouth samples years before diagnosis, people who carried this gum-disease bacterium had about a 60 percent higher risk of later developing pancreatic cancer.4 In a Chinese study, the same bacterium was found in 61 percent of esophageal cancers but in only 12 percent of the nearby normal tissue.5 See our articles on pancreatic cancer and esophageal cancer.
Gum Disease and Cancer Risk
In a long-term American study that examined the gums of more than 7,000 adults, people with severe gum disease had a 24 percent higher risk of developing cancer over the following years, and more than twice the risk of lung cancer.6
Silent Infections Under the Teeth
An infection at the tip of a tooth root, called apical periodontitis, often causes no pain. A worldwide review found that about half of adults have at least one, and that it is present in 39 percent of teeth that have had root canals.7 These infections are often missed on ordinary dental x-rays and are seen far better on a three-dimensional cone-beam CT scan. Whether they cause cancer has not been proven, but they are a continuous source of bacteria and inflammation.
Jawbone Cavitations: The German Research
A cavitation is a hollow area of dying or dead bone in the jaw, often at the site of an old tooth extraction, especially of wisdom teeth. German researchers call it fatty degenerative osteonecrosis of the jawbone. Johann Lechner, a dentist at the Clinic for Integrative Dentistry in Munich, and immunologist Volker von Baehr in Berlin have published a series of studies on these areas.
They found that bone from cavitations produces very high levels of RANTES, also called CCL5, an inflammatory signal that helps breast cancer grow and spread.8 In women with breast cancer, the levels in cavitation bone were about five times higher than those reported in breast cancer tissue itself.9 In a 2021 study of 39 women with breast cancer, every cavitation sample showed high RANTES, and in five women whose blood was tested before and after cavitation surgery, blood levels fell after surgery.10 These studies are small, but they suggest the jaw may be a hidden source of signals that feed cancer.
Mercury Amalgam Fillings
Silver-colored amalgam fillings are about half mercury. The European Union banned dental amalgam from January 1, 2025, under its rules to reduce mercury,11 and in 2020 the FDA recommended against amalgam for higher-risk groups, including pregnant and nursing women, children, and people with kidney or nervous system conditions.12 Biological dentists remove old amalgam fillings using special protective steps to limit mercury exposure during removal.
Dental Care Around Cancer Treatment
Dental problems are best addressed before chemotherapy, radiation to the head and neck, or bone-strengthening drugs such as zoledronic acid and denosumab, which can cause jaw bone damage. Ozone is widely used in biological dentistry to disinfect teeth, root canals and cavitations. See our articles on ozone therapy, hyperbaric oxygen and head and neck cancer.
How Cancer Expert MD Helps
Cancer Expert MD provides education and consultation for people with every type and stage of cancer, and specializes in Stage IV and metastatic cancer. Our book, The New Reality of Cancer, has a full chapter on chronic infection, including the mouth, covering viruses, mold, parasites, root canals, cavitations and amalgam, and how each is tested.
Frequently Asked Questions
Can mouth bacteria affect cancer?
Some can. Fusobacterium nucleatum is found inside many colorectal cancers and helps them resist chemotherapy, and carrying Porphyromonas gingivalis was linked to a higher risk of pancreatic cancer.
Can a root canal tooth be infected without pain?
Yes. Infection at the tip of the root is found in about 39 percent of root-canal-treated teeth worldwide and often causes no symptoms. A cone-beam CT scan shows it better than ordinary x-rays.
What is a jawbone cavitation?
A hollow area of dying bone in the jaw, often where a tooth was removed. German studies found these areas produce high levels of RANTES, an inflammatory signal linked to breast cancer growth.
Should dental work be done before cancer treatment?
Dental problems are best addressed before chemotherapy, head and neck radiation, or bone-strengthening drugs, which can make later dental work riskier.
About the author. Dr. Silver, MD, graduated from Temple University School of Medicine, trained as an interventional cardiologist, and has practiced medicine for nearly fifty years. A lymphoma survivor of about twenty-five years, he is co-author, with Dr. Lindmeier, DHSc, of The New Reality of Cancer: The Science of Recovery. Read more about Dr. Silver, MD.
Research by Dr. Lindmeier, DHSc, cancer educator and co-author of The New Reality of Cancer.
This article is for general education only and is not individual medical advice. Always consult your own doctor before making any changes to your care.
© 2026 Cancer Expert MD, Dr. Silver, MD, and Dr. Lindmeier, DHSc. All rights reserved. This article draws on the research in The New Reality of Cancer and may not be copied, republished or distributed without written permission.
For more in-depth information on this topic and many others, get our book, The New Reality of Cancer: The Science of Recovery.
More articles on integrative cancer treatments and all articles.
References
- de Martel C, Georges D, Bray F, Ferlay J, Clifford GM. Global burden of cancer attributable to infections in 2018: a worldwide incidence analysis. The Lancet Global Health. 2020;8(2):e180–e190.
- Yu T, Guo F, Yu Y, et al. Fusobacterium nucleatum promotes chemoresistance to colorectal cancer by modulating autophagy. Cell. 2017;170(3):548–563.
- Zepeda-Rivera M, Minot SS, Bouzek H, et al. A distinct Fusobacterium nucleatum clade dominates the colorectal cancer niche. Nature. 2024;628(8007):424–432.
- Fan X, Alekseyenko AV, Wu J, et al. Human oral microbiome and prospective risk for pancreatic cancer: a population-based nested case-control study. Gut. 2018;67(1):120–127.
- Gao S, Li S, Ma Z, et al. Presence of Porphyromonas gingivalis in esophagus and its association with the clinicopathological characteristics and survival in patients with esophageal cancer. Infectious Agents and Cancer. 2016;11:3.
- Michaud DS, Lu J, Peacock-Villada AY, et al. Periodontal disease assessed using clinical dental measurements and cancer risk in the ARIC study. Journal of the National Cancer Institute. 2018;110(8):843–854.
- Tibúrcio-Machado CS, Michelon C, Zanatta FB, et al. The global prevalence of apical periodontitis: a systematic review and meta-analysis. International Endodontic Journal. 2021;54(5):712–735.
- Lechner J, von Baehr V. RANTES and fibroblast growth factor 2 in jawbone cavitations: triggers for systemic disease? International Journal of General Medicine. 2013;6:277–290.
- Lechner J, von Baehr V. Hyperactivated signaling pathways of chemokine RANTES/CCL5 in osteopathies of jawbone in breast cancer patients: case report and research. Breast Cancer: Basic and Clinical Research. 2014;8.
- Lechner J, et al. Jawbone cavitation expressed RANTES/CCL5: case studies linking silent inflammation in the jawbone with epistemology of breast cancer. Breast Cancer: Targets and Therapy. 2021;13.
- European Union. Revision of the Mercury Regulation, ending the use of dental amalgam from January 1, 2025. 2024.
- US Food and Drug Administration. Recommendations about the use of dental amalgam in certain high-risk groups. September 24, 2020.
This article is for education only. It is not medical advice and does not diagnose or treat any condition. Cancer Expert MD has no financial relationship with any laboratory, drug maker, supplement company, clinic or hospital.
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