Unhealthy teeth and gums have been linked to the risk of several chronic diseases, such as heart disease, stroke and diabetes in the past.  But, according to Dr Haydée WT Jordão, from the Centre of Public Health at Queen’s University Belfast and lead author of the new study, “there is inconsistent evidence on the association between poor oral health and specific types of gastrointestinal cancers, which is what our research aimed to examine.”

To find out more, the researchers analysed data from 469,000 people in the UK, to see if there was indeed a connection between oral health conditions and the risk of a number of gastrointestinal cancers, including liver, colon, rectum and pancreatic cancer.

While no significant associations were observed on the risk of the majority gastrointestinal cancers and poor oral health, a substantial link was found for hepatobiliary cancer, the most common form of liver cancer.

Over the six years of follow up 4,069 developed gastrointestinal cancer. In 13% of these cases patients reported poor oral health. Those with poor oral health were more likely to be younger, female, living in deprived socioeconomic areas and consuming less than two portions of fruit and vegetables per day, according to the study published in the United European Gastroenterology Journal.

A preventable disease

Liver cancer is the sixth bigger cancer killer in the EU, claiming the lives of almost 60,000 people per year. The five-year survival rate for the disease across Europe is just 11% and approximately nine in 10 cases are in individuals over the age of 55. It is believed that up to half of cases of liver cancer are preventable, with risk factors often relating to lifestyle, such as being overweight or obese, smoking and alcohol consumption.

The biological mechanisms by which poor oral health may be more strongly associated with liver cancer, rather than other digestive cancers, is currently uncertain. One explanation is the potential role of the oral and gut microbiome in disease development. “The liver contributes to the elimination of bacteria from the human body,” stated Dr Jordão.

“When the liver is affected by diseases, such as hepatitis, cirrhosis or cancer, its function will decline and bacteria will survive for longer and therefore have the potential to cause more harm. One bacteria, Fusobacterium nucleatum, originates in the oral cavity but its role in liver cancer is unclear. Further studies investigating the microbiome and liver cancer are therefore warranted.”

• For more on good oral healthcare see our article Naturally healthy teeth and gums

“It has been shown that RA-associated antibodies, such as anti-citrullinated protein antibodies, are present well before any evidence of joint disease. This suggests they originate from a site outside of the joints,” said study author Dr Kulveer Mankia of Leeds Institute of Rheumatic and Muscoskeletal Medicine and the Leeds Biomedical Research Centre.

“Our study is the first to describe clinical periodontal disease and the relative abundance of periodontal bacteria in these at-risk individuals. Our results support the hypothesis that local inflammation at mucosal surfaces, such as the gums in this case, may provide the primary trigger for the systemic autoimmunity seen in RA.”

Mankia presented the results of his work at the recent Annual European Congress of Rheumatology (EULAR 2018).

Gum disease a consistent risk factor

The study included 48 at-risk individuals. Their level of risk was determined by the for anti-citrullinated protein antibodies, musculoskeletal symptoms but no clinical synovitis (inflammation of the synovial membrane). It also included 26 patients with RA and 32 healthy controls. The three groups were balanced for age, gender and smoking.

In results from the study, dentists diagnosed clinical gum disease in significantly more at-risk individuals than in healthy controls (73% vs. 38%). In addition, measurements of pocket depth, bleeding on probing, periodontal disease, and active periodontal disease, were all significantly greater in the at-risk individuals compared to controls. Even in non-smokers, periodontal disease and active peridontal disease were more prevalent in at-risk individuals compared to controls.

Another step towards prevention

Rheumatoid arthritis is a chronic inflammatory disease that affects a person’s joints, causing pain and disability. It can also affect internal organs. Rheumatoid arthritis is more common in older people, but there is also a high prevalence in young adults, adolescents and even children, and it affects women more frequently than men.

The prevalence of gum disease is increased in patients with RA and could be a key initiator of RA-related autoimmunity. This is because autoimmunity in RA is characterised by an antibody response to citrullinated proteins and the oral bacterium Porphyromonas gingivalis (Pg) is the only human pathogen known to be involved in the generation citrullinated proteins.

Gum disease is a known risk factor for chronic inflammatory diseases such as diabetes and cardiovascular disease, and there is also previous research to connect it with and rheumatoid arthritis. It has also recently been linked to a higher risk of cancer.  This data adds to what we know about the interactions between what are often considered separate parts of the body and body systems and the importance of whole body health.

“We welcome these data in presenting concepts that may enhance clinical understanding of the key initiators of rheumatoid arthritis,” said Professor Robert Landewé, Chairperson of the Scientific Programme Committee, EULAR. “This is an essential step towards the ultimate goal of disease prevention.”

• See also Naturally healthy teeth and gums and Beyond brushing – healthy teeth and gums protect the body in multiple ways

The first study, published in the Journal of the National Cancer Institute, used data from comprehensive dental exams performed on 7,466 people from four US states: Maryland, Minnesota, Mississippi, and North Carolina. These individuals were then followed for around 14 years.

During that time there was an overall 24% increase in the risk of developing cancer among those with severe gum disease, or periodontitis, compared to those who had mild to no periodontitis at the beginning of the study. Among those who had tooth loss – which can be a symptom of severe periodontitis – the increase in risk was 28%.

Further analyses on specific types of cancer showed that those with severe gum disease had more than double the risk of developing lung cancer, compared to those with no or mild periodontitis. Amongst those who had lost teeth (either partially or completely), there was an 80% increase in risk of colon cancer. The highest risks were in white people; in African-Americans the risk was low to non-existent.

While smokers are more likely to suffer from gum disease (and, of course, smoking also raises the risk for lung and colorectal disease), even amongst never smokers there was a two-fold higher risk of colorectal cancer in those with severe gum disease.

The researchers also uncovered a small increase in the risk of pancreatic cancer in patients with severe periodontitis. They found no links to increased risk of breast, prostate or blood/lymphatic cancer.

Pancreatic cancer

In a second study, published in the International Journal of Cancer, Finnish researchers also looked at the link between gum disease and cancer.

Scientists looked at data on over 68,000 adults, aged 29 and over, who had had at least one dental exam in 2001/2. These people were then followed for 10 years to track cancer cases and cancer deaths.

The most common dental procedure in this group was endodontic treatment (root canal) in 70.3% of patients, followed by treatment for gingivitis in 40.6% of patients and periodontitis treatment in 20.5%.

Results showed that periodontitis was associated with an overall 33% increased risk of dying from cancer. The mortality risk associated with gum disease among individuals with pancreatic cancer was far higher, at more than double the risk.

A previous paper by this same group found that a bacterium seen in periodontitis also occurs in gastrointestinal tumours adding weight to the idea that oral bacteria can spread from the mouth to other parts of the body.

Don’t brush this problem aside

Like most types of disease, gum disease is progressive. Gingivitis is an inflammation of the gums due to the presence of plaque. Periodontitis is the final stage of gum disease, with symptoms of bleeding and receding gums and loose teeth, which can be prevented by not allowing plaque to build-up. Left untreated it can lead to tooth loss.

According to the Centers for Disease Control and Prevention (CDC), around 47% of adults  who are over 30 years of age in the US have some type of periodontitis. With age, this rate increases, so that by age 65 years and over 70% will have this disease.

In the UK 3 out of every 4 adults over the age of 35 suffer from some form of gum disease.

There is already plenty of evidence linking gum disease with heart disease and stroke. This new research however, suggests even bigger implications for health in the prevention and early diagnosis and treatment of gum disease.

• For more on maintaining healthy teeth and gums see our article Naturally healthy teeth and gums. See also links top left.

While we may not think of it as such, the mouth is a unique environment where different species of bacteria live and compete. The health and balance withing this oral ecosystem, or microbiome, can be strongly influenced by other factors.

When you brush your teeth or change your diet, or are exposed to toxins in the environment (for instance by breathing in fumes), you can change this oral microbiome. What this unique study found was that exposure to toxic pesticides can have a significant impact on the oral ecosystem.

Researchers at the University of Washington analysed swabs taken from the mouths of 65 adult farm workers and 52 adults who didn’t work on farms. All lived in Washington’s Yakima Valley.

The farm workers all had higher blood levels of pesticides, and greater changes in their mouth bacteria than non-farm workers.

The most important finding was that among those farm workers in whom the organophosphate pesticide, Azinphos-methyl was detected in the blood, there were “significantly reduced abundances of seven common taxa of oral bacteria, including Streptococcus, one of the most common normal microbiota in the mouth,” said first author, Ian B. Stanaway.

Azinphos-methyl is an organophosphate insecticide. It works by inhibiting the action of neurotransmitters that activate certain muscles, but these neurotransmitters perform a wide range of functions in the body. It has been linked to reproductive problems and cancer. This pesticide is normally used on tree crops, such as apples – the type of crop workers in this study were working with.

Effects that persist

While many are not aware of this, not all streptococci are harmful and in fact many promote health. Changes in populations, species, and strains of Streptococcus, as well as from the genus, Halomonas, persisted into the winter, long after the growing season, when pesticide use is highest, was over, the researchers report.

The investigators suggest that this indicates a “long-lasting effects on the commensal microbiota have occurred,”

“The challenge becomes, what does this mean,” said principal investigator Elaine M. Faustman. “We don’t know,” she said, adding that “we depend on the micriobiome for many metabolic processes.”

Although the study identified these changes in the oral ecosystem, the researchers didn’t look at how they might link into health. Typically, however, modifying the number and types of bacterial strains in the mouth can lead to oral health problems.

For instance, Stanaway notes that “in other studies, changes in species and strains of Streptococcus have been associated with changes in oral health,”

Indeed, there is evidence that chronic periodontal infections are associated with an increased risk of cardiovascular disease and that the link may, in part, have to do with the way pathogenic oral bacteria affect the wider immune system function in the body.

The study’s findings were detailed in a paper published in the journal Applied and Environmental Microbiology.

Researchers say more work is necessary to tease out the different ways pesticide-triggered microbiome changes might affect human health.

Interesting future avenues to explore would be to look at the oral health of those who live in polluted areas or near farms, or whose diets contain foods high in pesticide residues.

• For more on this topic see our article Naturally healthy teeth and gums

A new study by Australian researchers has revealed that tooth decay (dental caries) can be stopped, reversed, and prevented without the need for the traditional ‘fill and drill’ approach that has dominated dental care for decades.

The results of the seven year study, published in Community Dentistry and Oral Epidemiology, found that the need for fillings was dramatically reduced through preventative oral care alone.

Fillings not always necessary

“It’s unnecessary for patients to have fillings because they’re not required in many cases of dental decay,” said the study’s lead author, Associate Professor Wendell Evans of the University of Sydney.

“This research signals the need for a major shift in the way tooth decay is managed by dentists…Our study shows that a preventative approach has major benefits compared to current practice.”

Evans goes on to say that for a long time it was believed that tooth decay was a rapidly progressive phenomenon and the best way to manage it was to identify early decay and remove it immediately in order to prevent a tooth surface from breaking up into cavities. After removing the decay, the tooth is then restored with a filling material – a process sometimes referred to as ‘drilling and filling’.

“However, 50 years of research studies have shown that decay is not always progressive and develops more slowly than was previously believed. For example, it takes an average of four to eight years for decay to progress from the tooth’s outer layer (enamel) to the inner layer (dentine). That is plenty of time for the decay to be detected and treated before it becomes a cavity and requires a filling,”says Evans.

‘Partnership’ between dentist and patient

In response to this Evans and his team have developed the Caries Management System (CMS) – a set of protocols which help dentists assess the risk of decay, interpret dental X-rays, and initiate specific treatment of early decay (decay that is not yet a cavity).

This system has four key points:

• Application of high concentration fluoride varnish by dentists to the sites of early decay
• Attention to home tooth brushing skills
• Restriction of between-meal snacks and beverages containing added sugar
• Risk-specific monitoring.

Tested on high risk patients it showed that early decay could be stopped and reversed and that the need for drilling and filling was reduced by 30-50 % compared to the control group.

“A tooth should be only be drilled and filled where an actual hole-in-the-tooth (cavity) is already evident,” said Evans.

He adds that the reduced decay risk and reduced need for fillings was understandably welcomed by patients. However, he emphasizes that patients play an important role in the success of the treatment and urges that dentists and patients must work in partnership for it to be most successful.

• For tips on how to manage your dental health naturally see our article Naturally healthy teeth and gums.
• Concerned about fluoride? See our article Q&A: What’s so bad about fluoride?

Atraumatic restorative treatment (ART) is becoming an increasingly popular approach to dental treatment in the West. It is especially appropriate for children and for dental patients with extreme fear of the dentist.

ART involves using the least invasive techniques, including hand tools to remove softened, or demineralised portions of the tooth, which is an early sing of dental decay.

However, if the demineralised material is not completely removed or the cavity is not properly disinfected, formation of a secondary cavity can occur.

The most common substance used for disinfection is chlorhexidine, but there is evidence that chlorhexidine can weaken tooth structure. As a result the hunt it on for natural disinfectants. Two substances with natural antibacterial activity, aloe vera, derived form the leaf of the aloe plant, and propolis, a resinous compound collected by honeybees, have emerged as potentially useful.

In a recent study published in Contemporary Clinical Dentistry Indian scientists attempted to measure the effectiveness of these substances in adolescent patients.

Reducing bacteria

They studied ten patients between the ages of 5 and 12 years old who had dental caries in a minimum of 3 teeth and measured bacterial counts on the tooth before treatment, after the softened enamel was scraped off using ART and the cavities were treated with distilled water (the control substance), aloe vera extract, or propolis extract for 60 seconds, and after the cavity had been filled.

Results showed a significant reduction in bacteria-forming colonies after disinfection with all three substances – however the final bacterial counts were significantly lower in the cavities treated with aloe vera or propolis than in the cavities treated with distilled water

Aloe vera and propolis were nearly equivalent in their ability to reduce bacterial infection within the cavities.

The small size of the study makes it hard to draw definite conclusions. However, both aloe vera and propolis have been shown in other studies to have antimicrobial characteristics. Aloe vera contains a wide range of anthraquinones, aromatic compounds that have been shown to be both antibacterial and antiviral. Propolis contains flavonoids, cinnamic acid, and other compounds that have also been shown to inhibit bacterial growth.

US researchers have found that if you use a power toothbrush the type of head it has can make the difference between a clean brush and one that harbours potentially risky bacteria

Solid-head power toothbrushes retain fewer bacteria compared to hollow-head toothbrushes

What is more, “Toothbrushes can transmit microorganisms that cause disease and infections” said lead researcher Professor Donna Warren Morris, RDH, MEd, professor at the University of Texas Health School of Dentistry.

Her research, published in the Journal of Dental Hygiene, found that solid-head power toothbrushes retain fewer bacteria than hollow-head in 9 out of 10 comparisons.

The study was conducted over a three-week period where participants brushed twice daily with one out of three randomly assigned power toothbrushes. Participants used non-antimicrobial toothpaste and continued their flossing routine throughout the study, but refrained from using other dental products like mouthwash.

“The packaging on most power toothbrushes won’t distinguish between a hollow-head and a solid-head design,” Morris said. “The best way to identify a solid-head design is through the connection to the body of the power toothbrush. Naturally, there will be some space to connect the two parts but a significant portion will be solid, up to the bristles or brush head.”

During the study the brush heads were exposed to five categories of oral microorganisms: anaerobes and facultative microorganisms, yeast and mould, oral streptococci and oral enterococci anaerobes, Porphyromonas gingivalis and Fusobacterium species.

Many of these microorganisms have been associated with systemic diseases, though data linking a germy toothbrush with systemic disease is lacking.

“We do know and there are studies that have linked Fusobacterium to colorectal cancer. Some of these other bacteria have been linked with cardiovascular disease,” Morris said. “There is a high association with gum disease and cardiovascular disease. Researchers have been able to culture the same bacteria around the heart that causes gum disease. ”

“A solid-head design allows for less growth of bacteria and bristles should be soft and made of nylon,” Morris said. “It is also important to disinfect and to let your toothbrush dry between uses. Some power toothbrushes now include an ultraviolet system or you can soak the head in mouthwash for 20 minutes.”

Good dental hygiene also dictates you change your brush regularly and especially after an illness or respiratory infection to prevent reinfection.

• See also our article Naturally healthy teeth and gums

In this randomised, controlled, double-blind trial Finnish researchers investigated the effects of orally administered Lactobacillus rhamnosus GG (LGG) and Bifidobacterium animalis subsp. lactis BB-12 (BB-12) on the number mutans streptococci (MS, a group of different bacteria in the Streptococcus mutans family) in the mouth. They also looked at the amount of plaque, gingival inflammation and the oral microbiota in healthy young adults.

To test the effect of the probiotics a group of 60 healthy volunteers were divided into two groups which received lozenges containing a combination of LGG and BB – or lozenges without added probiotics for 4 weeks.

In those taking the probiotic lozenge the scientists observed decreased levels of plaque index and a lower incidence of gingivitis. No such changes were found in the control group.

However, no changes in levels of mutans streptococci in saliva were detected in either group suggesting the probiotics had an additive or balancing effect.

Writing in the journal Clinical Oral Investigations, the authors conclude “Short-term consumption of LGG and BB-12 decreased the amount of plaque which was associated with a clinical impact: a decrease in gingival inflammation”.

Health implications beyond the mouth

Gingivitis is a growing problem in the developed world. In its early stages it causes red swollen or bleeding gums, bad breath and discomfort. If left untreated, it can progress, increasing the risk of tooth loss as well as bone and joint damage.

In severe cases the bacteria that cause infection and inflammation can get into your bloodstream and be circulated throughout your entire body, including the brain and heart. This is one reason why gum disease now linked with strokes or heart disease.

A new solution

Probiotics are living microorganisms, principally bacteria, that are safe for human consumption and have beneficial effects on human health. Using them to improve dental health is a relatively new area of exploration, though it is increasingly being considered as an answer to the emergence of antibiotic-resistant bacteria.

One 2009 review found the weight of the evidence showed the following benefits:

• Probiotics incorporated into dairy products were able to neutralise acidic conditions in the mouth and interfere with cariogenic (cavity-causing) bacteria.

• Patients with periodontal disease who used chewing gum or lozenges containing probiotics saw their periodontal status improve.

• Probiotics in gargling solutions or gum inhibit the production of volatile sulphur compounds that contribute to bad breath.

Previous research has suggested that the probiotic L. reuteri Prodentis can inhibit plaque and have anti-inflammatory and antimicrobial effects that could make it useful in maintain health teeth and gums, though not all studies have found a positive effect.

Successful outcomes may be dependent on which type of probiotic is used, though comparative studies are rare.

The Spanish researchers say that their report, which appears in the Journal of Agricultural and Food Chemistry, could lead to the development of natural products that ward off dental diseases with fewer side effects.

Dental diseases are extremely common throughout the world. Cavities, periodontal disease and tooth loss affect an estimated 60 to 90 % of the global population.

The problems start when certain bacteria in the mouth get together and form biofilms, which are communities of bacteria that are difficult to kill. They form plaque and produce acid, which starts damaging teeth. Brushing, a good toothpaste, drinking water and other methods can help get rid of bacterial plaques, but the effects can be limited.

In addition, currently used mouthwashes can change the colour of the gums and alter taste, so people are less likely to use them for as long as they should – and of course the antibacterial triclosan found in many dental preparations is simply toxic and fluoride is increasingly coming under similar scrutiny.

Some research has suggested that polyphenols, grape seed extract and wine can slow bacterial growth, so lead researcher M. Victoria Moreno-Arribas’ and her team team decided to test them under realistic conditions for the first time.

They grew cultures of bacteria responsible for dental diseases as a biofilm.

The researchers then dipped the biofilms for a couple of minutes in different liquids, including red wine, red wine without the alcohol, red wine spiked with grape seed extract, and water and 12% ethanol for comparison.

Red wine with or without alcohol and wine with grape seed extract were the most effective at getting rid of the bacteria.