Tooth loss is often accepted as a natural part of aging, but what if there was a way to better identify those most susceptible without the need for a dental exam? New research led by investigators at the Harvard School of Dental Medicine suggests that machine learning tools can help identify those at greatest risk for tooth loss and refer them for further dental assessment in an effort to ensure early interventions to avert or delay the condition.

The study, published in PLOS ONE, compared five algorithms using a different combination of variables to screen for risk. The results showed those that factored medical characteristics and socioeconomic variables, such as race, education, arthritis, and diabetes, outperformed algorithms that relied on dental clinical indicators alone.

Study lead investigator Hawazin Elani said: “Our analysis showed that while all machine-learning models can be useful predictors of risk, those that incorporate socioeconomic variables can be especially powerful screening tools to identify those at heightened risk for tooth loss”.

The approach could be used to screen people globally and in a variety of healthcare settings, even by non-dental professionals, she added. In the study, the researchers used data comprising nearly 12,000 adults from the National Health and Nutrition Examination Survey to design and test five machine-learning algorithms and assess how well they predicted both complete and incremental tooth loss among adults based on socioeconomic, health, and medical characteristics.

The results of the analysis point to the importance of socioeconomic factors that shape risk beyond traditional clinical indicators.



Economically advanced Japan has plentiful dentists, as well as a universal health insurance system, yet it also has oral care-related inequities, according to a new study. A team of researchers at the University of Tsukuba examined a huge set of claims and check-up data in search of regional and socioeconomic trends. Their findings included the key observation that regional lower income and educational levels may correlate with failing to seek preventive dental treatment. The study was reported in The Lancet Regional Health — Western Pacific.

Associate Prof. Takahiro Mori said: “We conducted an ecological [population-level] study to try and grasp how people access oral care across Japan, and what they seek. This was the first-ever national-level attempt to examine regional inequality in dental care use in our country”.

The 216 million pieces of data in this study spanned April 2017 to March 2018 and included indicators such as outpatient visits, use of outreach (home) services, and treatments such as fillings and dentures. The data were also examined in different regions in relation to socioeconomic factors, such as income and education.

Perhaps the most important finding regarded income and education, explained the study’s senior author, Prof. Nanako Tamiya: “Access to preventive care was negatively correlated with areas that showed lower income and education levels. This means people in those areas may be less likely to seek preventive dental measures such as calculus removal (i.e., cleaning). This, in turn, can make it harder to preserve teeth, and necessitates more severe treatment”.


New survey data collected by the Oral Health Foundation and Align Technology has found the profound impact of the pandemic on the way UK adults view their smiles. More than half (58%) of British adults surveyed responded that they have changed the way they see their smile as a result of online video calls, with a third (33%) now more aware of the colour of their teeth and nearly a quarter (24%) more conscious about the alignment of their teeth.

The new research, released as part of National Smile Month, shows that one-in-ten (11%) UK adults feels self-conscious seeing their smile during an online meeting or video call.

Dr Nigel Carter OBE, Chief Executive of the Oral Health Foundation, believes the growth and increased use of digital technologies has led to an increased exposure of the smile: “Physical interactions have been limited over the last 12 months, and for many, have been replaced with gatherings online. This technology has been an invaluable tool, whether it be facilitating business meetings or allowing grandparents to see their newborn grandchildren for the first time. It has also led to us seeing our own face, and smile, far more than we are used to”.

A healthy mouth can be achieved through an effective oral health routine at home, as well as regular dental visits. The key components of an effective oral health routine are brushing twice a day with a fluoride toothpaste for two minutes, cleaning in between the teeth daily with interdental brushes or floss, and cutting down on how much and how often you have sugary foods and drinks.



Peri-implantitis, a condition where tissue and bone around dental implants becomes infected, besets roughly one-quarter of dental implant patients, and currently there’s no reliable way to assess how patients will respond to treatment of this condition.

To that end, a team led by the University of Michigan School of Dentistry developed a machine-learning algorithm to assess an individual patient’s risk of regenerative outcomes after surgical treatments of peri-implantitis.

The algorithm is called Fast and Robust Deconvolution of Expression Profiles (FARDEEP). In the study, researchers used FARDEEP to analyse tissue samples from a group of patients with peri-implantitis who were receiving reconstructive therapy. They quantified the abundance of harmful bacteria and certain infection-fighting immune cells in each sample.

Patients who were at low risk for periodontal disease showed more immune cells that were highly adept at controlling bacterial infections, said Yu Leo Lei, senior author.

The team was surprised that the types of cells associated with better outcomes for implant patients challenge conventional thinking, said Lei: “Much emphasis has been placed on the immune cell types that are more adept at wound healing and tissue repair. However, here we show that immune cell types that are central to microbial control are strongly correlated with superior clinical outcomes.

Surgical management can reduce bacterial burdens across all patients, however, only the patients with more immune cell subtypes for bacterial control can suppress the recolonisation of pathogenic bacteria and show better regenerative outcomes”.

In the future, it may be possible to predict the risk of peri-implantitis before a dental implant is placed, he said. More human clinical trials are required before FARDEEP is ready to be used widely by clinicians.



A new study’s findings dispel the misconception that patients and providers are at high risk of catching Covid-19 at the dentist’s office. Covid-19 spreads mainly through respiratory droplets, and dental procedures are known to produce an abundance of aerosols – leading to fears that flying saliva during a cleaning or a restorative procedure could make the dentist’s chair a high-transmission location.

Ohio State University researchers set out to determine whether saliva is the main source of the spray, collecting samples from personnel, equipment and other surfaces reached by aerosols during a range of dental procedures.

By analysing the genetic makeup of the organisms detected in those samples, the researchers determined that the watery solution from irrigation tools, not saliva, was the main source of any bacteria or viruses present in the spatter and spurts from patients’ mouths.

Even when low levels of the Covid-19 virus were detected in the saliva of asymptomatic patients, the aerosols generated during their procedures showed no signs of the coronavirus. In essence, from a microbial standpoint, the contents of the spray mirrored what was in the office environment.

Lead author Purnima Kumar, professor of periodontology at Ohio State said: “Getting your teeth cleaned does not increase your risk for Covid-19 infection any more than drinking a glass of water from the dentist’s office does … These findings should help us open up our practices, make ourselves feel safe about our environment and, for patients, get their oral and dental problems treated — there is so much evidence emerging that if you have poor oral health, you are more susceptible to Covid”.

The study was published in the Journal of Dental Research.



The combination of a carbohydrate-heavy diet and poor oral hygiene can leave children with early childhood caries (ECC), a severe form of dental decay that can have a lasting impact on their oral and overall health.

A few years ago, scientists from the University of Pennsylvania School of Dental Medicine found that the dental plaque that gives rise to ECC is composed of both a bacterial species, Streptococcus mutans, and a fungus, Candida albicans. The two form a sticky symbiosis, known scientifically as a biofilm, that becomes extremely virulent and difficult to displace.

A new study from the group offers a strategy for disrupting this biofilm by targeting the yeast-bacterial interactions that make ECC plaques so intractable. In contrast to some current treatments for ECC, this treatment uses an enzyme specific to the bonds that exist between microbes.

The study was published in mBio and senior author, Geelsu Hwang said: “We thought this could be a new way of approaching the problem of ECCs that would intervene in the synergistic interaction between bacteria and yeast. This offers us another tool for disrupting this virulent biofilm”.

The work builds off findings from a 2017 paper by Hwang and colleagues, including Hyun (Michel) Koo of Penn Dental Medicine, which found that molecules call mannans on the Candida cell wall bound tightly to an enzyme secreted by S. mutans, glycosyltransferases (Gftb). In addition to facilitating the cross-kingdom binding, Gftb also contributes to the stubbornness of dental biofilms by manufacturing gluelike polymers called glucans in the presence of sugars.



Maintenance of good oral health is more important than use of antibiotics in dental procedures for some heart patients to prevent a heart infection caused by bacteria around the teeth, according to a new American Heart Association (AHA) scientific statement published today in the Association’s flagship journal, Circulation.

Infective endocarditis (IE), also called bacterial endocarditis, is a heart infection caused by bacteria that enter the bloodstream and settle in the heart lining, a heart valve or a blood vessel. Viridans group streptococcal infective endocarditis (VGS IE) is caused by bacteria that collect in plaque on the tooth surface and cause inflammation and swelling of the gums. There’s been concern that certain dental procedures may increase the risk of developing VGS IE in vulnerable patients.

The new guidance affirms previous recommendations that only four categories of heart patients should be prescribed antibiotics prior to certain dental procedures to prevent VGS IE due to their higher risk for complications from the infection:

  • those with prosthetic heart valves or prosthetic material used for valve repair;
  • those who have had a previous case of infective endocarditis;
  • adults and children with congenital heart disease; or,
  • people who have undergone a heart transplant.


It has been over a decade since recommendations for preventing IE were updated amid concerns of antibiotic resistance due to overprescribing. The AHA’s 2007 guidelines more tightly defined which patients should receive preventive antibiotics before certain dental procedures to the four high-risk categories. This change resulted in about 90% fewer patients requiring antibiotics.



Older adults with more harmful than healthy bacteria in their gums are more likely to have evidence for amyloid beta – a key biomarker for Alzheimer’s disease – in their cerebrospinal fluid (CSF), according to new research from the New York University College of Dentistry and Weill Cornell Medicine. However, this imbalance in oral bacteria was not associated with another Alzheimer’s biomarker called tau.

The study, published in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, adds to the growing evidence of a connection between gum disease and Alzheimer’s.

Lead study author Angela Kamer said: “To our knowledge, this is the first study showing an association between the imbalanced bacterial community found under the gumline and a CSF biomarker of Alzheimer’s disease in cognitively normal older adults. The mouth is home to both harmful bacteria that promote inflammation and healthy, protective bacteria. We found that having evidence for brain amyloid was associated with increased harmful and decreased beneficial bacteria”.

The researchers studied 48 healthy, cognitively normal adults aged 65+. Participants underwent oral examinations to collect bacterial samples from under the gumline, and lumbar puncture was used to obtain CSF in order to determine the levels of amyloid beta and tau. To estimate the brain’s expression of Alzheimer’s proteins, the researchers looked for lower levels of amyloid beta (which translate to higher brain amyloid levels) and higher levels of tau (which reflect higher brain tangle accumulations) in the CSF.

The results showed that individuals with an imbalance in bacteria, with a ratio favouring harmful to healthy bacteria, were more likely to have the Alzheimer’s signature of reduced CSF amyloid levels.



A new study by scientists at Kyoto University and the University of Fukui reports that an antibody for one gene – USAG-1 – can stimulate tooth growth in mice suffering from tooth agenesis, a congenital condition. The paper was published in Science Advances.

Although the normal adult mouth has 32 teeth, about 1% of the population has more or fewer due to congenital conditions. Scientists have explored the genetic causes for cases having too many teeth as clues for regenerating teeth in adults.

According to Katsu Takahashi, one of the lead authors of the study, the fundamental molecules responsible for tooth development have already been identified: “The morphogenesis of individual teeth depends on the interactions of several molecules including BMP, or bone morphogenetic protein, and Wnt signaling”.

BMP and Wnt are involved in much more than tooth development. They modulate the growth of multiple organs and tissues. Consequently, drugs that directly affect their activity are commonly avoided, since side effects could affect the entire body.

Guessing that targeting the factors that antagonize BMP and Wnt specifically in tooth development could be safer, the team considered the gene USAG-1. The scientists therefore investigated the effects of several monoclonal antibodies for USAG-1. Monoclonal antibodies are commonly used to treat cancers, arthritis, and in vaccine development.

The study is the first to show the benefits of monoclonal antibodies on tooth regeneration and provides a new therapeutic framework for a clinical problem that can currently only be resolved with implants and other artificial measures.



Current advice from the America Dental Association tells you that if your gums bleed, make sure you are brushing and flossing twice a day because it could be a sign of gingivitis, an early stage of gum disease. So if you are concerned, see your dentist. However, a new University of Washington (UW) study suggests you should also check your intake of vitamin C.

“When you see your gums bleed… You should try to figure out why your gums are bleeding. And vitamin C deficiency is one possible reason,” said the study’s lead author Philippe Hujoel, a practising dentist and professor of oral health sciences in the UW School of Dentistry.

Hujoel’s study, published in Nutrition Reviews, analysed published studies of 15 clinical trials in six countries, involving 1,140 predominantly healthy participants, and data from 8,210 US residents surveyed in the Centers for Disease Control and Prevention’s Health and Nutrition Examination Survey. The results showed that bleeding of the gums on gentle probing, or gingival bleeding tendency, were associated with low vitamin C levels in the bloodstream. The researchers found that increasing daily intake of vitamin C in those people with low vitamin C plasma levels helped to reverse these bleeding issues.

Hujoel does recommend people attempt to keep an eye on their vitamin C intake through incorporation of non-processed foods such as kale, peppers or kiwis into their diet, and if you can’t find palatable foods rich in vitamin C, to consider a supplement of about 100-200 milligrams a day.





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