Nina Garlo MSc, is a health and science journalist who works as communications manager at Koite Health Ltd.

Nina Garlo, MSc

Image Credit: © stock.adobe.com / KatrinaEra

The oral cavity houses more than 700 types of bacteria. While some bacterial species are beneficial for dental and overall health, in some cases, they can play a role in the development of serious systemic illnesses.

Studies show maintaining a balanced microbial ecosystem in the mouth is crucial for oral health, and it has a significant impact on how the body responds to various diseases. Oral dysbiosis, or an imbalanced oral microbiome, or ecosystem, can lead to various health issues ranging from common dental problems such as caries and periodontal disease to systemic conditions such as heart disease, Alzheimer’s disease, and diabetes.

Dysbiosis often leads to the formation of biofilms, which in turn can provide a protective environment for bacterial growth. Biofilms may even shield bacteria from the body’s defense mechanisms and antimicrobial treatments, promoting chronic infections in the body and leading to an increased cancer risk.

A study published in the international, peer-reviewed 

 journal also reveals that the presence of oral biofilmobstructs wound healing and can lead to persistent or recurrent infections. Meanwhile, the severity and prognosis of diseases like chronic rhinosinusitis and cystic fibrosis are linked to the presence of biofilm in the mouth, the study shows.

Recent studies have revealed a potential link between oral dysbiosis and the development of life-threatening digestive cancers.

 Digestive cancers include cancers located in the esophagus, stomach, liver, pancreas, colon, and rectum. Their incidence and related mortality are increasing worldwide, with 63% of new cases of digestive cancers and 65% of related deaths occurring in Asia, followed by Europe and North America.

Scientists believe many digestive cancer forms are influenced by various environmental factors that can be potentially changed. These include smoking, diet, alcohol consumption, and obesity. Some recent evidence also suggests a role of the human oral microbiota in the development of digestive cancers. 

is one colorectal cancer-associated bacterial species commonly found in the mouth. However, many other oral pathogens can play a role in the development of cancer as well.

Exposing the Oral Bacteria-Pancreatic Cancer Link

 (Td), one of the bacteria responsible for periodontitis, may cause pancreatic cancer.

 Caused by the abnormal and uncontrolled growth of cells in the pancreas, pancreatic cancer is one of the deadliest forms of cancer. Around half of all new cases are diagnosed in people aged 75 or over.

Td can enter the bloodstream through inflamed gums, spreading to other parts of the body. If left untreated and undiagnosed, periodontal disease contributes to the development and spread of cancer and cancer deaths – not only from oral cancer, but especially pancreatic cancer, explains Timo Sorsa, professor of oral and maxillofacial diseases at the University of Helsinki, about the findings of the study.

Professor Sorsa points out Td bacterium share a specific enzyme with some types of gut cancer. This enzyme is called Treponema denticola chymotrypsin-like proteinase, or dentilisin, and it is usually found in the mouth, where it is known to contribute to severe periodontitis. However, this same enzyme has also been observed in malignant and life-threatening tumors.

In the oral cavity, dentilisin not only contributes to gum disease but also triggers other enzymes that promote cancer. These enzymes are called matrix metalloproteinases (MMPs), and they break down the material between cells and cell membranes, making it easier for cancer to invade healthy tissue. Prof Sorsa stresses this connection raises concerns about potential health issues related to dentilisin in the oral cavity.

With research showing virulence factors from gum disease bacteria could spread from the mouth to other parts of the body and take part in central mechanisms of cancer-related tissue destruction.

Since then, supplementary research has supported the study’s findings. One report by Prof Sorsa’s team released in the 

 examined registry data for over 10 years on more than 68,000 adults in Finland who had made a primary dental healthcare visit. This revealed that periodontitis was associated with a 33% increased risk for overall cancer mortality. The mortality risk associated with gum disease among individuals with pancreatic cancer was far higher, with a more than twofold increased risk, the study shows.

From Fast Diagnosis to a Quick Onset of Treatment

The links revealed so far between oral bacteria and cancer developments inspired Prof. Sorsa’s team to search ways to help prevent cancerous developments. One potential solution is to detect gum infections in their initial stages through early diagnosis. By quickly identifying gum disease with a chair-side aMMP-8 rapid test, researchers believe that certain cancers might be more preventable due to faster treatment of the underlying issue of gum inflammation.

Out of all MMP enzymes, especially active MMP-8 enzyme has been found to be elevated in patients suffering from gum disease leading to periodontal connective tissue destruction, Prof Sorsa explains.

Estimated to affect as many as half of the global population, often without symptoms, periodontitis is a widespread health concern. Early detection of these diseases is important because it allows for intervention and treatment before irreversible damage occurs. Using biomarkers like aMMP-8, clinicians can spot subtle inflammation and tissue damage, allowing them to start treatment before the disease becomes visible.

The aMMP-8 rapid test can non-invasively measure and assess active periodontal adhesive tissue loss and the risk of its progression within 5 minutes. The test complements the diagnosis, follow-up, and maintenance treatment of periodontitis and peri-implantitis, explains Prof Sorsa.

According to Prof. Sorsa the mouthrinse aMMP-8 rapid test can also detect prediabetes/diabetes and tissue destructive oral side effects due to radiotherapy treatment for head and neck cancers.

Advanced Approaches for Treating Oral Diseases

Periodontal and peri-implant diseases are conditions that affect the supporting structures of teeth and dental implants and can lead to tooth loss if left untreated. While gingival infections can develop for various reasons, one key factor is the buildup of biofilm on the surfaces of teeth due to inadequate oral hygiene.

While tooth decay is the most common disease in the world, and inflammation of the supporting tissues of the teeth is the sixth most common disease in the world, the medical community struggles to find new solutions to combat these infections. Prof. Sorsa notes that dental plaque bacteria are responsible for a staggering 95% of oral ailments. He also highlights the significance of modern antibacterial methods in promoting good oral hygiene and effective plaque removal. Research reveals that antibacterial photodynamic therapy (aPDT) is a promising approach to treat bacterial infections – even ones that do not respond well to antibiotics.

Until recently, aPDT treatment for improving oral health was solely available at dental clinics. Professor Sorsa highlights the work of Finnish scientists who have pioneered an at-home oral health-enhancing device based on aPDT. This device provides a drug-free alternative for the management and prevention of oral and gum diseases, he says.

Based on a light-activated antibacterial effect, the patented home-use device slows down plaque formation and significantly reduces the burden of harmful bacteria in the mouth. aPDT treatment administered regularly at home is suitable for patients of all ages, but it is particularly recommended for those with a history of problems with common oral diseases, tooth decay, and gum disease.

The Crucial Role of Oral Hygiene in Cancer Care

Brushing and flossing on a regular basis is key to maintaining a healthy mouth by removing dental plaque from the surfaces of teeth and interdental spaces. However, it is not always enough. Good oral hygiene requires adequate motor skills for effective brushing and flossing, as well as mental skills for consistent oral care. On the other hand, even when brushing teeth perfectly, studies show that even the most effective electric toothbrush only removes about 65% of harmful oral bacteria from the mouth.

The key to overall well-being is good oral hygiene, especially for cancer patients who must maintain a high-calorie diet to fight the disease, notes Prof Dr Tuomas Waltimo from the University of Basel.

Prof Waltimo also acts as a private dentist at a clinic that offers dental services to patients with special dental needs, for example patients undergoing cancer treatments. He reminds that cancer treatments often bring along side-effects that can require special attention. Mucositis, as one example, can lead to generalised infection and even be life-threatening.

Mucositis is the painful inflammation and ulceration of the mucous membranes lining the digestive tract. It can occur anywhere along the gastrointestinal (GI) tract, but oral mucositis refers to the inflammation and ulceration that occurs specifically in the mouth. Maintaining good oral hygiene habits is crucial for the treatment of oral mucositis.

All of this research has been commercialized into Lumoral, a new solution currently available in Europe. Designed to support regular dental hygiene routines, Lumoral combines a dual-wavelength LED mouthpiece with an Indocyanine green mouthrinse to destroy harmful oral bacteria. The solution helps patients achieve and maintain gum health, and prevents inflammation in the oral cavity.

Tommi Pätilä, MD, PhD, a cardiac and transplant surgeon at the New Children’s Hospital (HUS) in Helsinki, Finland, and a key scientist behind the development of the novel Lumoral device, stresses that oral biofilm bacteria are the cause of 95% of dental diseases.

"The tricky thing about oral infections is that they may have no symptoms. If dental plaque is not removed thoroughly, it can pass through the gums into the bloodstream," says Dr Pätilä.

So how can you prevent this from happening?

Brushing your teeth thoroughly and using dental floss or interdental brushes is the first step. You also need to visit your dentist or dental hygienist regularly. Adding regular antibacterial dual light treatment to the oral hygiene routine is useful for everyone but particularly important for those who have already had problems with tooth loss or gum inflammation, Dr Pätilä adds.

Good oral hygiene is of paramount importance also in the management of oral mucositis. Initial findings suggest Lumoral treatment might help prevent and potentially treat oral mucositis, but this hypothesis requires further scientific research to confirm. Prof. Waltimo says a new study is starting at the University of Helsinki to examine that question.

Maier T. Oral Microbiome in Health and Disease: Maintaining a Healthy, Balanced Ecosystem and Reversing Dysbiosis. 

. 2023; 11(6):1453. https://doi.org/10.3390/microorganisms11061453

Silva DNA, Casarin M, Monajemzadeh S, Bezerra BB, Lux R, Pirih FQ. The Microbiome in Periodontitis and Diabetes. 

. 2022;3:859209. Published 2022 Apr 8. doi:10.3389/froh.2022.859209

Arnold M, Abnet CC, Neale RE, et al. Global Burden of 5 Major Types of Gastrointestinal Cancer. 

. 2020;159(1):335-349.e15. doi:10.1053/j.gastro.2020.02.068

Vestby LK, Grønseth T, Simm R, Nesse LL. Bacterial Biofilm and its Role in the Pathogenesis of Disease. 

. 2020;9(2):59. Published 2020 Feb 3. doi:10.3390/antibiotics9020059

Pignatelli P, Nuccio F, Piattelli A, Curia MC. The Role of 

 in Oral and Colorectal Carcinogenesis. 

. 2023;11(9):2358. Published 2023 Sep 20. doi:10.3390/microorganisms11092358

Reitano E, de'Angelis N, Gavriilidis P, et al. Oral Bacterial Microbiota in Digestive Cancer Patients: A Systematic Review. 

. 2021;9(12):2585. Published 2021 Dec 14. doi:10.3390/microorganisms9122585

Nieminen MT, Listyarifah D, Hagström J, et al. Treponema denticola chymotrypsin-like proteinase may contribute to orodigestive carcinogenesis through immunomodulation. 

. 2018;118(3):428-434. doi:10.1038/bjc.2017.409

NHS Inform. Pancreatic Cancer. NHS Inform. Updated November 14, 2023. Accessed January 9, 2024. 

https://www.nhsinform.scot/illnesses-and-conditions/cancer/cancer-types-in-adults/pancreatic-cancer/

Heikkilä P, But A, Sorsa T, Haukka J. Periodontitis and cancer mortality: Register-based cohort study of 68,273 adults in 10-year follow-up. 

. 2018;142(11):2244-2253. doi:10.1002/ijc.31254

Sorsa T, Gursoy UK, Nwhator S, et al. Analysis of matrix metalloproteinases, especially MMP-8, in gingival creviclular fluid, mouthrinse and saliva for monitoring periodontal diseases. 

. 2016;70(1):142-163. doi:10.1111/prd.12101

Sorsa T, Nwhator SO, Sakellari D, et al. aMMP-8 Oral Fluid PoC Test in Relation to Oral and Systemic Diseases. 

. 2022;3:897115. Published 2022 Jun 10. doi:10.3389/froh.2022.897115

Pakarinen S, Saarela RKT, Välimaa H, Heikkinen AM, Kankuri E, Noponen M, Alapulli H, Tervahartiala T, Räisänen IT, Sorsa T, et al. Home-Applied Dual-Light Photodynamic Therapy in the Treatment of Stable Chronic Periodontitis (HOPE-CP)—Three-Month Interim Results. 

Liu Y, Qin R, Zaat SAJ, Breukink E, Heger M. Antibacterial photodynamic therapy: overview of a promising approach to fight antibiotic-resistant bacterial infections. 

. 2015;1(3):140-167. Published 2015 Dec 1.

Aggarwal N, Gupta S, Grover R, Sadana G, Bansal K. Plaque Removal Efficacy of Different Toothbrushes: A Comparative Study. 

. 2019;12(5):385-390. doi:10.5005/jp-journals-10005-1669

Articles

Oral dysbiosis, a condition where imbalanced oral bacteria can lead to a range of health issues is at the center of the link between poor oral health and systemic diseases, and emphasizes the crucial role of oral hygiene in promoting overall health.