Study shows commonly used mouthwash could make saliva significantly more acidic

The first study looking at the effect of chlorhexidine mouthwash on the entire oral microbiome has found its use significantly increases the abundance of lactate-producing bacteria that lower saliva pH, and may increase the risk of tooth damage.

A team led by Dr Raul Bescos from the University of Plymouth's Faculty of Health gave a placebo mouthwash to subjects for seven days, followed by seven days of a chlorhexidine mouthwash.

At the end of each period, the researchers carried out an analysis of the abundance and diversity of the bacteria in the mouth - the oral microbiome - as well as measuring pH, saliva buffering capacity (the ability to neutralise acids in the mouth), lactate, glucose, nitrate and nitrite concentrations.

The research, published in Scientific Reports today, found using chlorhexidine mouthwash over the seven days led to a greater abundance of species within the families of Firmicutes and Proteobacteria, and fewer Bacteroidetes, TM7 and Fusobacteria. This change was associated with an increase in acidity, seen in lower salivary pH and buffering capacity.

Overall, chlorhexidine was found to reduce microbial diversity in the mouth, although the authors cautioned more research was needed to determine if this reduction in diversity itself increased the risk of oral disease.

One of the primary roles of saliva is to maintain a neutral pH in the mouth, as acidity levels fluctuate as a result of eating and drinking. If saliva pH gets too low, damage can occur to the teeth and mucosa - tissue surrounding the teeth and on the inside of the mouth.

The research also confirmed findings from previous studies indicating that chlorhexidine disrupted the ability of oral bacteria to turn nitrate into nitrite, a key molecule for reducing blood pressure. Lower saliva and blood plasma nitrite concentrations were found after using chlorhexidine mouthwash, followed by a trend of increased systolic blood pressure. The findings supported earlier research led by the University that showed the blood pressure-lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash rather than water.

Dr Bescos said: "There is a surprising lack of knowledge and literature behind the use of these products. Chlorhexidine mouthwash is widely used but research has been limited to its effect on a small number of bacteria linked to particular oral diseases, and most has been carried out in vitro.

"We believe this is the first study to look at the impact of 7-day use on the whole oral microbiome in human subjects."

Dr Zoe Brookes and Dr Louise Belfield, Lecturers in the Peninsula Dental School at the University of Plymouth, are co-authors of the study.

Dr Belfield said: "We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria - whether in the mouth or the gut - are essential for sustaining human health."

Dr Brookes added: "As dental clinicians, we need more information on how mouthwashes alter the balance of oral bacteria, so we can prescribe them correctly. This paper is an important first step in achieving this.

"In the face of the recent COVID-19 outbreak many dentists are now using chlorhexidine as a pre-rinse before doing dental procedures. We urgently need more information on how it works on viruses"

Half of 65+ adults lack dental insurance; poll finds strong support for Medicare coverage

Oral care coverage acts as a strong draw for enrolling in Medicare Advantage plans

IMAGE: KEY FINDINGS FROM THE NATIONAL POLL ON HEALTHY AGING POLL OF ADULTS AGED 65-80 view more 

CREDIT: UNIVERSITY OF MICHIGAN

Nearly all older Americans support adding a dental benefit to the Medicare program that covers most people over age 65, according to a new national poll that also reveals how often costs get in the way of oral health for older adults.

Ninety-three percent of people between the ages of 65 and 80 favor including dental coverage in traditional Medicare, though the percentage dropped to 59% when they were asked if they'd favor it even if they had to pay more for their Medicare benefits.

Just over half of the older adults polled (53%) said they currently have dental coverage. Half of this group are covered as employees or retirees, or spouses of employees.

Another quarter said they have dental coverage because they've chosen to get their Medicare coverage through a Medicare Advantage plan offered by a commercial insurance company. In fact, 72% of those with Medicare Advantage coverage said they'd chosen their plan in part because it covered dental care.

Whether they had insurance or not, cost plays a role in dental decisions, the poll finds. One in five of the older adults polled said they had delayed getting dental care, or gone without it, in the past two years.

The majority of these respondents said cost, or insurance problems, played a role in this decision. Those without dental insurance, and those with lower incomes, were more likely to say they'd delayed or gone without oral care.

The new results come from the National Poll on Healthy Aging, carried out by the University of Michigan Institute for Healthcare Policy and Innovation with support from AARP and Michigan Medicine, U-M's academic medical center. It involved a national sample of more than 1,030 adults aged 65 to 80 who answered a range of questions about their own oral health and dental health policy.

"These results suggest that health care providers and policymakers should seek solutions to better identify and address how cost and other factors act as barriers to dental care among older adults," says Domenica Sweier, Ph.D., D.D.S.

Sweier, a clinical associate professor at the U-M School of Dentistry, helped develop the poll questions and analyze the results. She adds that as providers and policy makers continue to seek solutions, "This will be important to preventing health and social consequences of unmet oral health needs in this population."

Differences across the over-50 age range

A previous National Poll on Healthy Aging report looked at dental health, including insurance and cost factors, among people in their 50s and early 60s. Only one in four of those polled said they lacked dental insurance, but half said they did not know how they would get dental coverage after they retired and some assumed that traditional Medicare would cover their dental care needs.

"Across the spectrum of ages, dental care and coverage vary, and cost plays a major role," says Preeti Malani, M.D., director of the poll and a professor of internal medicine at U-M with special training in the care of older adults. "We know that poor oral health can affect everything from social interactions to eligibility for surgery, so it's important for health professionals as well as policymakers to understand what older adults are experiencing."

One in four of the adults over 65 polled (27%) said they were embarassed by the condition of the teeth, and about the same percentage rated their overall dental health as fair or poor.

The role of dental care costs

One in three hadn't been to the dentist for preventive care such as a cleaning in at least a year. When the research team cross-referenced this with household income, they found that those with incomes over $60,000 were nearly twice as likely as those with incomes less than $30,000 to have gone to the dentist in the past year.

Nearly half of the poll sample (46%) said they were missing teeth but didn't have a denture or implant to fill the gap.

"Coverage of dental care, as well as vision and hearing care, is critical for the long-term health of our population" says Alison Bryant, Ph.D., senior vice president of research for AARP. "Even simple teeth cleanings may not be affordable to seniors living on fixed incomes, so having coverage for dental benefits may help address that problem."

The poll also shines additional light on the growing body of evidence linking oral health and overall health and wellbeing.

Those who said their overall physical or mental health were fair or poor also visited the dentist's office less often, and were more likely to say their oral health was poor. Problems with dry mouth related to medication use, and challenges eating a healthy diet because of untreated dental problems, could make these issue worse, says Malani.

The National Poll on Healthy Aging results are based on responses from a nationally representative sample of 1,039 adults aged 65 to 80 who answered a wide range of questions online. Questions were written, and data interpreted and compiled, by the IHPI team. Laptops and Internet access were provided to poll respondents who did not already have them.

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A full report of the findings and methodology is available at http://www.healthyagingpoll.org, along with past National Poll on Healthy Aging reports.

Patients prescribed opioids after tooth extraction report worse pain

The use of opioids to soothe the pain of a pulled tooth could be drastically reduced or eliminated altogether from dentistry, say University of Michigan researchers.

More than 325 dental patients who had teeth pulled were asked to rate their pain and satisfaction within six months of extraction. Roughly half of the study's patients who had surgical extraction and 39% who had routine extraction were prescribed opioids.

The U-M researchers compared the pain and satisfaction of those who used opioids to those who didn't.

"I feel like the most important finding is that patient satisfaction with pain management was no different between the opioid group and non-opioid group, and it didn't make a difference whether it was surgical or routine extraction," said study co-author Romesh Nalliah, clinical professor and associate dean for patient services at the U-M School of Dentistry.

Surprisingly, patients in the opioid group actually reported worse pain than the non-opioid group for both types of extractions, Nalliah said.

The researchers also found that roughly half of the opioids prescribed remained unused in both surgical and nonsurgical extractions. This could put patients or their loved ones at risk of future misuse of opioids if leftover pills are not disposed of properly.

The findings are scheduled to appear March 13 in JAMA Network Open.

"The real-world data from this study reinforces the previously published randomized-controlled trials showing opioids are no better than acetaminophen and nonsteroidal anti-inflammatory drugs for pain after dental extraction," said study co-author Chad Brummett, director of the Division of Pain Research and of Clinical Research in the Department of Anesthesiology at Michigan Medicine, U-M's academic medical center.

Brummett co-directs the Michigan Opioid Prescribing Engagement Network, or Michigan OPEN, which has developed, tested and shared guidelines for the use of opioids in patients with acute pain from surgery and medical procedures.

"These data support the Michigan OPEN prescribing recommendations calling for no opioids for the majority of patients after dental extractions, including wisdom teeth extraction," he said.

The results have big implications for both patients and dentists, and suggest prescribing practices need an overhaul, Brummett and Nalliah said.

The American Dental Association suggests limiting opioid prescribing to seven days' supply, but Nalliah believes that's too high.

"I think we can almost eliminate opioid prescribing from dental practice. Of course, there are going to be some exceptions, like patients who can't tolerate nonsteroidal anti-inflammatories," he said. "I would estimate we can reduce opioid prescribing to about 10% of what we currently prescribe as a profession."

For dentists, many of whom are sole proprietors, this new information means they needn't worry so much about unhappy patients changing practices if they aren't prescribed strong opioids. Alternatives such as nonsteroidal anti-inflammatory drugs or acetaminophen appear to control pain better, and patient satisfaction remains high.

Nalliah gives two possible reasons for this. First, dentists may have prescribed opioids in only the toughest cases, which would have resulted in more pain regardless.

"Or alternatively, and this is the reason I tend to accept, is that our study concurs with previous studies that suggest opioids are not the most effective analgesic for acute dental pain," Nalliah said.

"Dentists are torn between wanting to satisfy patients and grow business and limiting their opioid prescribing in light of the current crisis. I think it's an extremely liberating finding for dentists who can worry more about the most effective pain relief rather than overprescribing for opioids."

Dentists account for about 6% to 6.5% of U.S. opioid prescriptions--a relatively small amount. But the study notes that dentists are among the most common prescribers for minors, and for many patients, dental opioid prescriptions are their first exposure.

Dental teams could play an important role in early diagnosis of Type 2 and pre-diabetes

UNIVERSITY OF BIRMINGHAM

Dental teams could play an integral role in identifying people at high risk of developing Type 2 diabetes as well as in the early detection of the condition in those who are undiagnosed, new research suggests.

The systematic review, led by researchers in the University of Birmingham, found that using risk assessment tools such as patient questionnaires and point of care blood testing within a dental surgery setting could lead to better outcomes for patients and improved management of the condition.

Severe periodontitis - or gum disease - is significantly linked to Type 2 diabetes, a condition that is thought to affect approximately 422 million adults globally (according to the World Health Organisation). As T2DM is asymptomatic in its early stages, many individuals can remain undiagnosed for many years. However, with established links between compromised glycaemic status and oral health, dental professionals could be vital in the identification of the condition.

Lead researcher Professor Iain Chapple, Head of the University of Birmingham's School of Dentistry said: "Our review identified positive attitudes of physicians, dental team members, patients and the public towards risk assessing and early case detection of diabetes and pre-diabetes within the dental surgery. Patients also strongly supported tests being undertaken that provided immediate results.

"Not only does this demonstrate that there may be benefit in engaging the dental workforce to identify these cases, but also shows a need for a more joined up approach to care pathways between physicians and dental practitioners."

The work builds on joint international guidance published last year on gum disease and diabetes, which recommends closer working pathways between oral health care professionals and physicians, and a commissioning standard issued in 2019 by NHS England, setting out a vision for the implementation of such joint working practices. The Birmingham team were heavily involved with both publications.

The microbes in your mouth, and a reminder to floss and go to the dentist

Oral microbiome was subject of crowd-sourced study by CSU, Denver museum

COLORADO STATE UNIVERSITY

IMAGE: GENETICS OF TASTE LAB RESEARCHERS AND VOLUNTEERS ENROLL PARTICIPANTS IN THE ORAL MICROBIOME STUDY. view more 

CREDIT: DENVER MUSEUM OF NATURE & SCIENCE

Most people know that good oral hygiene - brushing, flossing, and regular dental visits - is linked to good health. Colorado State University microbiome researchers offer fresh evidence to support that conventional wisdom, by taking a close look at invisible communities of microbes that live in every mouth.

The oral microbiome ­- the sum total of microorganisms, including bacteria and fungi, that occupy the human mouth - was the subject of a crowd-sourced, citizen science-driven study by Jessica Metcalf's research lab at CSU and Nicole Garneau's research team at the Denver Museum of Nature & Science. Published in Scientific Reports, the study found, among other things, a correlation between people who did not visit the dentist regularly and increased presence of a pathogen that causes periodontal disease.

For the experiments, carried out by Garneau's community science team in the Genetics of Taste Lab at the museum, a wide cross-section of museum visitors submitted to a cheek swab and answered simple questions about their demographics, lifestyles and health habits. Microbial DNA sequencing data analyzed by Metcalf's group revealed, broadly, that oral health habits affect the communities of bacteria in the mouth. The study underscored the need to think about oral health as strongly linked to the health of the entire body.

"Our study also showed that crowdsourcing and using community scientists can be a really good way to get this type of data, without having to use large, case-controlled studies," said Zach Burcham, a postdoctoral researcher and the paper's lead author. Senior author Metcalf is an associate professor in the Department of Animal Sciences and a member of CSU's Microbiome Network.

Cheek swabs

Back in 2015, paper-co-author Garneau and her team trained volunteer citizen scientists to use large swabs to collect cheek cells from museum visitors ­­- a naturally diverse population - who consented to the study. These trained citizen scientists helped collect swabs from 366 individuals - 181 adults and 185 youth aged 8 to 17.

The original impetus for the study was to determine whether and to what extent the oral microbiome contributes to how people taste sweet things. In collecting this data, which was also reported in the paper, the researchers noted more significant data points around oral health habits.

To help translate the data, Garneau turned to Metcalf's team of experts at CSU. Burcham and the microbiome scientists employed sophisticated sequencing and analysis tools to determine which microbes were present in which mouths. Sequencing for the data was performed in collaboration with scientists in Rob Knight's group at University of California San Diego. A nutrition team from Michigan State University also brought in expertise on the importance of child and maternal relationships to the data analysis.

"Together, we had a dream team for using community science to answer complicated questions about human health and nutrition, using state-of-the-art microbial sequencing and analysis," Garneau said.

Flossing and regular dental care

The study grouped people who flossed or didn't floss (almost everyone said they brushed, so that wasn't a useful data point). Participants who flossed were found to have lower microbial diversity in their mouths than non-flossers. This is most likely due to the physical removal of bacteria that could be causing inflammation or disease.

Adults who had gone to a dentist in the last three months had lower overall microbial diversity in their mouths than those who hadn't gone in 12 months or longer, and had less of the periodontal disease-causing oral pathogen, Treponema. This, again, was probably due to dental cleaning removing rarer bacterial taxa in the mouth. Youth tended to have had a dental visit more recently than adults.

Youth microbiomes differed among males and females, and by weight. Children considered obese according to their body mass indices had distinct microbiomes as compared to non-obese children. The obese children also tended to have higher levels of Treponema, the same pathogen found in adults who hadn't been to the dentist in more than a year. In other words, the researchers saw a possible link between childhood obesity and periodontal disease. "This was very interesting to me, that we were able to detect these data in such a general population, with such a variable group of people," Burcham said.

Other data uncovered: The microbiomes of younger participants, mostly in the 8- to 9-year-old range, had more diversity than those of adults. However, adult microbiomes varied more widely from person to person. The researchers think this is due to the environments and diets of adults being more wide-ranging than children.

They also saw that people who lived in the same household shared similar oral microbiomes.

"When you look at families who live together, you find they share more of those rare taxa, the bacteria that aren't found as often in higher abundances," Burcham explained. It was a data point that underscored the relevance of one's built environment in relationship to the microbial communities in our bodies.

Working on the mouth study was fascinating, albeit outside Burcham's normal scope; he is usually focused on studying microbial ecology of decomposition.

"I think how our lives are essentially driven by our microbiomes, and affected by our microbiomes, is interesting, no matter what system we're looking at," Burcham said.