​岡山ヒルトップ歯科

Study uses artificial intelligence for gingivitis detection

HONK KONG: The applications of artificial intelligence (AI) in dentistry have been widely explored in recent years. However, a recent study is one of the first to employ AI to detect gingivitis, enabling monitoring of the effectiveness of patients’ plaque control. The technology has the potential for improving the early detection and prevention of oral and systemic diseases associated with periodontal disease, one of the most prevalent oral diseases globally. According to the World Health Organization, nearly one-third of cases of periodontal disease are severe.

The interdisciplinary study was a collaboration between researchers from Hong Kong, Guangzhou in China and Kuala Lumpur in Malaysia. In it, the researchers trained and tested a novel AI model on a data set of over 567 intra-oral photographs of gingiva with varying degrees of inflammation. The study found that the AI algorithm can accurately (> 90%) analyse patients’ intra-oral photographs to detect signs of inflammation, such as redness, swelling and bleeding along the gingival margin. Its accuracy in identifying sites with and without gingival inflammation is close to that of a dentist.

Lead researcher Dr Walter Yu-Hang Lam, a clinical assistant professor in prosthodontics at the University of Hong Kong, said in a press release: “Many patients do not attend regular dental check-ups, and they only seek dentists to alleviate pain when their teeth are at the end stage of dental disease, in which tooth loss is inevitable, and only expensive rehabilitative treatments are available. Our study shows that AI can be a valuable screening tool in detecting and diagnosing gum disease, one of the key indicators of periodontal disease, allowing earlier intervention and better health outcomes for the population,” he noted.

Discussing the benefits of using intra-oral photographs in conjunction with AI technology, lead author Dr Reinhard Chun-Wang Chau, a clinical research coordinator in restorative dental sciences at the University of Hong Kong, said that, based on intra-oral photographs, patients could see which areas they had not cleaned well and seek dental care earlier.

The researchers now plan to make the technology accessible to elderly and underserved communities to improve their oral health outcomes and reduce healthcare disparities.

The study, titled “Accuracy of artificial intelligence-based photographic detection of gingivitis”, was published on 26 April 2023 in the International Dental Journal, ahead of inclusion in an issue.

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Skipping nightly toothbrushing could heighten cardiovascular disease risk

In a recent study published in Scientific Reports, researchers determined whether the frequency of brushing one's teeth increases the risk of cardiovascular diseases (CVDs) in patients aged 20 years or older.

Background

Several previous studies have emphasized the importance of perioperative oral care and management in patients with malignant cancers, as well as respiratory, gastrointestinal, and cardiovascular diseases.

Many of these reports have focused on the time of tooth brushing in the context of demineralization of the teeth. However, these reports did not explore the relationship between toothbrush time and systemic diseases, including CVD.

About the study

The individuals included in this study were hospitalized at the Osaka University Hospital in Japan between April 2013 and March 2016 for examination, surgery, or treatment. Patients who visited the hospital's Unit of Dentistry to seek dental treatment, perioperative oral care, and screening for infection were also considered for the analysis.

Taken together, the 1,675 study participants were classified into four groups. Group MN reported brushing their teeth twice daily, once after waking up and again at night, whereas group Night reported brushing their teeth only once at night. Group M reported brushing their teeth only after waking up, whereas group None did not brush their teeth.

The number of participants in each group was 409, 751, 164, and 259, respectively. The number of men in group M was four times that of women in this group.

Groups Night and MN had the highest percentage of individuals who reported brushing their teeth after lunch at 44.9% and 24%, respectively. Few study participants in groups M and None reported brushing their teeth after lunch. 

The researchers evaluated each participant's age, gender, smoking history, and follow-up results. In addition, four independent investigators retrospectively reviewed the dental and medical records of all study participants.

One dentist investigated oral health, pre-hospitalization frequency and time of toothbrushing, the depth of periodontal pockets, the extent of tooth mobility, and teeth count.

Several cardiovascular events were considered in the study, which included CVD-related hospitalization for heart failure, arrhythmia, myocardial infarction, angina pectoris, and valvular and aortic diseases requiring surgery.

A proportional hazards model was used to assess the association between the observation items and the occurrence of cardiovascular events and life prognosis. For subgroup analysis stratified by smoking status, Kaplan-Meier curves were used to estimate the time from the participants' dentistry visit to study endpoints of death or the end of the study period. All statistical analyses considered P-values less than 0.05 as significant.

Study findings

Based on blood samples obtained at hospital admission, all participants had similar C-reactive protein (CRP), hemoglobin, albumin, creatinine, and HbA1c levels but different brain natriuretic peptide (BNP) levels. Groups MN and Night had significantly higher survival rates as compared to Group None.

All study participants had similar smoking statuses; however, they had varying dental parameters. For example, group MN had the most participants with dental pocket depths exceeding eight millimeters (mm). As compared to groups Night and M, more patients in groups None and MN had a dental mobility index of three.

In their clinical practice, the researchers encountered many middle-aged and older people who did not brush their teeth at night. In their interviews, many of these patients mentioned they consumed alcohol at night, which caused them to become too tired and not brush their teeth.

In each study group, several individuals reported not brushing their teeth at night. This may be due to habits learned from their parents during childhood, lifestyle, and regional variations. General disinterest in dental hygiene is another reason people do not brush their teeth at night and after lunch. 

Breakfast and lunch have been shown to increase the risk of intraoral deposits that remain in the mouth throughout the day and, as a result, increase the risk of dental caries and other periodontal diseases. Thus, brushing only in the morning after waking up is insufficient and implies poor oral hygiene. Furthermore, brushing one's teeth at night is crucial to maintain good oral health, which supports the hypothesis that intraoral bacterial load surges during sleep due to reduced salivary flow.

Conclusions

The study findings reiterate that while brushing teeth before breakfast is necessary, brushing teeth at night before going to bed is even more important to prevent CVDs.

Journal reference:

• Isomura, E.T., Suna, S., Kurakami, H. et al. (2023). Not brushing teeth at night may increase the risk of cardiovascular disease. Scientific Reports 13(10467). doi:10.1038/s41598-023-37738-1

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Dental care important and difficult for those with Alzheimer’s

Dear Doctors: Our grandmother is 76 years old and has Alzheimer's disease. My siblings and I are helping our mom care for her. We'd like to know what to expect regarding dental care. Her dentist has other patients with Alzheimer’s and says it gets difficult to treat them as the disease advances. We want to be prepared.

Dear Reader: Oral care is a key component in maintaining overall good health and well-being. When you regularly brush, have cleanings and see a dentist, you protect more than just your teeth and gums. You also safeguard your general health.

The bacteria associated with gingivitis and gum disease cause chronic inflammation. It not only taxes the body, but it also opens the door to additional disease and illness. Research has revealed a clear link between poor gum health and an increased risk of heart disease, including coronary artery disease.

Individuals living with Alzheimer's disease gradually become unable to perform daily living activities. This includes dental care. Changes occurring in the brain also begin to interfere with the ability to swallow. The medical term for this difficulty is dysphagia. The result is that dementia patients often breathe in, or aspirate, the food or beverage they are trying to swallow. When gum disease is present, dysphagia increases the risk of bacterial lung infection, such as aspiration pneumonia. Dental problems can also make eating painful, and often play a role in malnutrition in these patients. This adds urgency to maintaining good oral health.

In the earliest stages of dementia, patients are typically able to care for their own teeth and participate in professional dental care. If repair or restoration is necessary, this is the optimal time for it to be carried out.

As cognitive abilities decrease, the focus shifts to preventive behaviors. Someone with Alzheimer's may not remember to brush their teeth, or why it is important to do so. It falls to caregivers to remind them, and often to demonstrate the practice alongside them. If someone wears dentures, caregivers will need to take over the task of cleaning and sanitizing them, and to help the individual clean their gums and tongue.

Routine and predictability are important in dementia care. Experts in the field advise caregivers to help the individual develop a dental care routine, and to carry it out the same way each day. This adds structure to the person's life and may extend their ability to participate in their own oral care.

As a patient's dementia advances, behavioral and psychological symptoms, such as depression and aggression, often arise. When coupled with the loss of cognitive abilities, this makes ongoing dental care difficult.

In advanced dementia, caregivers often actively help the person care for their teeth or do it for them. Professional dental care also becomes a challenge. If a dental procedure is required to safeguard someone's health, sedation may be required. Caregivers must then balance the need for the procedure with the patient's inability to give informed consent.

None of this is easy. The challenges of dental care in dementia are widely known. Your local dental society will be able to provide references to professionals with experience helping these patients.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

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Researchers discover biofilm-inhibiting molecule

A naturally occurring molecule may be the key to reducing plaque and the incidence of dental cavities, according to research recently published in Antibiotics.

A collaborative team led by scientists at Ben-Gurion University of the Negev in Israel, Sichuan University in China, and the National University of Singapore reported that 3,3′-Diindolylmethane (DIM), a naturally occurring molecule, also known as bisindole, reduced biofilms that produce plaque and cavities by 90%. They also asserted that the molecule has anticarcinogenic properties (Antibiotics, June 6, 2023, Vol. 12:6, 1017).

According to the researchers, bisindole inhibits the growth of biofilms created by Streptococcus mutans, bacteria that grows in the moist and sugary atmosphere of the mouth after food has been ingested. The team also noted that the molecule has low toxicity, meaning it could be added safely to toothpastes and mouthwashes to improve oral hygiene.

 

The research was supported by the International Research and Development Program of Sichuan and a SMART innovation grant from Singapore.

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The growing problem of tooth wear

Alyn Morgan breaks down the issues associated with tooth wear, both physical and beyond, and the potential for digital management.

Across the dental profession, dental caries has been the key disease we have treated for many years. More recently, tooth wear has been recognised as an increasing problem. It may become a much greater challenge for clinicians in the years to come.

Preventing and managing tooth wear and tooth surface loss (TSL) will be key to the conservative and holistic dentistry that we strive for. This means that we need effective ways to predict and monitor wear – could digital technologies help with this?

Impact of tooth wear

Tooth wear is a multifactorial condition that can be slow to progress. Therefore, symptoms may not appear until late in the disease process (Wetselaar et al, 2020). As colleagues will know, tooth wear is typically the result of attrition, erosion or abrasion – or a combination of these.

There are several possible chemical and mechanical causes. These include an acidic diet, gastric reflux, abrasive food or dental products, and parafunction. The data varies widely regarding the prevalence of moderate to severe tooth wear among the global population. However, it is estimated to be between 20% and 45% in adults (Schlueter and Luka, 2018).

Patients with tooth wear are nine times more likely to report dissatisfaction with their teeth (Al-Omiri et al, 2006). Higher levels of tooth wear have also been linked to a lower oral health-related quality of life (Mehta et al, 2023).

Severe versions of the condition have been linked to psychological discomfort and disability in patients. This is regardless of socio-demographic factors or specific clinical characteristics (Li and Bernabé, 2016).

As such, it is important that the dental team is able to help patients manage tooth wear. Through this, they can minimise its impact and prevent further progression.

Management of tooth wear

As is the case in many areas of dentistry, patients tend to be motivated to seek help for tooth wear primarily due to aesthetic concerns.

One study found this to be true for 59% of participants, compared with 40% complaining of sensitivity, 17% of function issues and 14% of pain (Wazani et al, 2012). Another study found similar results, despite endodontic treatment being indicated in 11% of tooth wear patients evaluated, all of whom presented with late-stage dental erosion and exposure of the pulp (Sivasithamparam et al, 2003).

Personally, I see an increasing number of patients present with fractures in the teeth due to prolonged wear. These are especially common in older people, and the fractures can be catastrophic for their natural dentition.

This, combined with the complex aetiology behind the development of the condition and an ageing population, means that effective preventive and clinical management of tooth wear is crucial, albeit challenging.

Where possible, a focus should be placed on prevention and early diagnosis to avoid potentially extensive treatment and rehabilitation. This requires ongoing assessment and recording of tooth surface levels. Additionally, collecting comparative data that can be utilised over time to evaluate TSL.

The Tooth Wear Evaluation System (TWES) 2.0 has been proven to be a reliable tool in the assessment of tooth wear severity (Roehl et al, 2022). It also contains a decision tree relating to the taxonomy of tooth wear to aid diagnosis.

Digital potential

There have also been developments in the digital techniques available to support management of tooth wear.

For example, intraoral scanners may be useful in the continuous monitoring of TSL, as they have shown promise in being able to detect minor tissue loss over time (Witecy et al, 2021). Comparing scans from consecutive patient appointments can provide a relatively easy way to measure the pace of TSL, and help clinicians to detect a potential issue and deliver early intervention.

These same images could also be used for digital models that facilitate occlusal management. This would help to prevent further wear in the future. Existing technologies are not yet capable of supporting this workflow efficiently, but this is definitely food for thought.

There is currently scope for digital solutions to be incorporated within the planning of restorative treatment following tooth wear diagnosis.

Face scanning, CBCT and intraoral scans may be combined to facilitate 3D planning that enables the design of restorations that are the most appropriate length, level, shape and colour for the patient’s face (Yar, 2023).

Additionally, digital solutions can be used to design and fabricate night guards to help protect new restorations and prevent further wear. The potential advantages of digital impressions and manufacturing processes in this area include shorter turnaround and chair times, as well as a simpler workflow for the dental team.

Prevention is better than cure

There is definitely still scope for improvement within all these digital workflows, but the early results are very encouraging.

Of course, prevention is always better than cure. Anything that can be done to avoid tooth wear in the first place must be prioritised. Digital technologies could help clinicians to risk assess for tooth wear, and restore dentition once the condition is under control. This would be a very valuable tool for the future.

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Why dental hygienists and therapists are key to expanding access to dental care

Access to dental care, and the attainment of oral health, is critical for our overall health. Yet millions of people in the UK lack dental treatment.

Dental therapists, with their particular training and expertise, have emerged as a viable solution to bridge the gap and improve access to dental care.

So much so that, despite being incorrectly briefed on their exact title, Prime Minister Rishi Sunak highlighted dental therapists as key to dental reform when unveiling the 15-year NHS Long Term Workforce Plan at the end of June.

‘In the first instance, I am delighted to see dentistry highlighted as part of the Long Term Plan,’ said Miranda Steeples, president of the BSDHT.

‘If we compare this to the NHS Long Term Plan in 2019, dentistry was not mentioned at all, even when this plan was supposed to focus on prevention.

‘It is no mean feat that dentistry has been considered in this document. And that money is promised to go towards training more dentists, dental therapists and dental hygienists.

‘I hope that the dental schools, especially the Dental Schools Council, will be consulted about how this is expected to work with regards to dental school staffing and infrastructure on clinics.’

The access crisis

Limited access to dental care in the UK is disproportionately affecting vulnerable populations. Specifically, low-income individuals, children, and the elderly are most acutely impacted.

Dental therapists have gained recognition in recent months, with some key opinion leaders describing the role as a cost-effective and practical solution to address the access crisis.

However, it is this perception that has many concerned health leaders are just attempting to cut corners, offering NHS dentistry at a cheaper rate to the government – to the detriment of those working within the profession.

‘What is missed in the NHS Long Term Workforce Plan is a need to increase numbers of dental nurses to support these clinicians,’ says Miranda.

‘Otherwise, dental therapists will not be able to carry out the work being asked of them. The dental nursing profession needs support as well.

‘Not to mention dental technicians – their numbers are falling.

‘And if there are not enough dental technicians working in dental laboratories, who will make the NHS work for all the additional dentists?’

The access crisis

Despite emphasising their importance, Rishi Sunak forgot dental therapist’s title, describing them as ‘therapists or dental’. During his speech he promised to increase training for dental hygienist and therapists by more than 500 by 2031/32.

‘Much has been made of the prime minister getting our name, or professional title, wrong in the press conference,’ Miranda highlighted.

‘But this is distracting from more important matters.

‘If we as professionals cannot get this right – if, in common parlance, or on conference delegate name badges – our full correct title is not used, then how can we expect those outside of dentistry to not simply call us “therapists”?

‘The BSDHT has done a lot of work in recent time around using correct titles. We believe this is essential moving forward.’

Evidence of success

Numerous studies have demonstrated the effectiveness of dental therapists in improving access to care.

Countries such as New Zealand and Australia, where dental therapists have been integrated into the dental workforce for decades, access to care has significantly improved.

Additionally, the American Dental Association (ADA) and the World Health Organisation (WHO) have recognised the value of dental therapists. Now, they advocate for their expanded role in the delivery of oral healthcare.

However, it is essential dental therapist’s skills are utilised effectively with an integrated dental practice setting. And Miranda believes involving dental hygienists and therapists in the discussions moving forward is the only way to manage this properly.

‘There was a comment from the Prime Minister: “We expect them to do more dental work”,’ Miranda said.

‘As in dental therapists may take on more of the workload in NHS dentistry, as per the recent contract amendments.

‘This is both pleasing and disappointing; direct access has been possible for the last 10 years for dental hygienists and dental therapists, but only recently within the NHS.’

Cross the finish line

She added: ‘Now that there is an exodus of dentists who want to do this work, decisions have been taken about dental therapists and what we can or want to do. But all without our consent or input.

‘Why would we want to work in a system without being in receipt of the benefits that are offered to dentists? And of benefits that are insufficient to keep dentists in that system?

‘The barrier still persists with the issue of exemptions and PGDs for the use of high strength fluoride products and local anaesthetics.

‘Maybe this plan, or the Dentistry Recovery Plan, will help move this work along so it can finally cross the finish line and support proposals.’

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Tooth regrowth medicine set to enter clinical trials

A medicine to grow new teeth is set to enter clinical trials in July next year after being developed in Japan. 

Following the clinical trials, the research team plans to have the medicine ready for general use in 2030.

If successful, they believe the tooth regrowth medicine could be a ‘game changer’ for dentistry.

The medicine will allow people to grow new teeth and is intended for those missing a full set of permanent teeth due to congenital reasons. For example, the medicine is aimed at children aged two to six with anodontia, a congenital condition that causes the complete absence of teeth.

The research team are working to get the drug ready for human use once they have confirmed it is safe and doesn’t cause harm

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‘Every dentist’s dream’

Katsu Takahashi is lead researcher and head of the dentistry and oral surgery department at the Medical Research Institute Kitano Hospital in Osaka, Japan. He said: ‘The idea of growing new teeth is every dentist’s dream.

‘I’ve been working on this since I was a graduate student. I was confident I’d be able to make it happen.’

He also added: ‘In any case, we’re hoping to see a time when tooth regrowth medicine is a third choice alongside dentures and implants.’

OSAKA -- A Japanese research team is making progress on the development of a groundbreaking medication that may allow people to grow new teeth, with clinical trials set to begin in July 2024.

The tooth regrowth medicine is intended for people who lack a full set of adult teeth due to congenital factors. The team is aiming to have it ready for general use in 2030.

In prior animal experiments, the medicine prompted the growth of "third-generation" teeth following baby teeth and then permanent adult teeth.

"The idea of growing new teeth is every dentist's dream. I've been working on this since I was a graduate student. I was confident I'd be able to make it happen," said Katsu Takahashi, lead researcher and head of the dentistry and oral surgery department at the Medical Research Institute Kitano Hospital in the city of Osaka.

Anodontia is a congenital condition that causes the growth of fewer than a full set of teeth, present in around 1% of the population. Genetic factors are thought to be the major cause for the one-tenth of anodontia patients who lack six or more teeth, a condition categorized as oligodontia. These conditions are also known as tooth agenesis. People who grow up with tooth agenesis struggle with basic abilities like chewing, swallowing and speaking from a young age, which can negatively impact their development.

After completing a dentistry degree, Takahashi went on to graduate studies in molecular biology at Kyoto University in 1991. Afterwards, he studied in the U.S.

Around that time, research around the world had begun to pinpoint genes that, when deleted, would cause genetically modified mice to grow fewer teeth. "The number of teeth varied through the mutation of just one gene. If we make that the target of our research, there should be a way to change the number of teeth (people have)," Takahashi said of his thoughts at the time.

Global attention

It was around 2005, when he delved further into the subject at Kyoto University after returning to Japan, that he began to see a bright path for his continued research. The researchers found that mice lacking a certain gene had an increased number of teeth. A protein called USAG-1, synthesized by the gene, was found to limit the growth of teeth. In other words, blocking the action of that protein could allow more teeth to grow.

Takahashi's research team narrowed their focus onto USAG-1, and developed a neutralizing antibody medicine able to block the protein's function. In experiments in 2018, mice with a congenitally low number of teeth were given medicine that resulted in new teeth coming through. The research results were published in a U.S. scientific paper in 2021, and gained much attention as the beginnings of the world's first tooth regeneration medicine.

Work is now underway to get the drug ready for human use. Once confirmed to have no ill effects on the human body, it will be aimed at treating children aged 2 to 6 who exhibit anodontia. "We hope to pave the way for the medicine's clinical use," Takahashi said.

Medicine could be game-changer

If successful, a drug to regenerate teeth may be a game-changer for the entire field of dentistry.

Animals including sharks and some reptile species can continuously regrow teeth. It's been assumed that humans only grow two sets of teeth in their lifetime, but in fact, there is evidence that we also have the "buds" for a third set.

Around 1% of the population exhibits the converse of anodontia: hyperdontia, a congenital condition causing a higher-than-normal number of teeth. According to research by Takahashi's team, one in three such cases manifests as the growth of a third set of teeth. Takahashi believes that in most cases, humans' ability to grow a third set was lost over time.

When the researchers applied the drug to ferrets, they grew an additional seventh front tooth. As the new teeth grew in between the existing front teeth and were of the same shape, the medicine is thought to have induced the generation of third-set teeth in the animals.

When treatment of teeth is no longer possible due to severe cavities or erosion of the dental sockets, known as pyorrhea, people lose them and need to rely on dental appliances such as dentures. The ability to grow third-generation teeth could change that. "In any case, we're hoping to see a time when tooth-regrowth medicine is a third choice alongside dentures and implants," Takahashi said.

For further information or inquiries about Takahashi's research, please visit https://www.kitano-hp.or.jp/toothreg/ (in Japanese).

(Japanese original by Mirai Nagira, Science & Environment News Department)

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Dental Hygiene May Play Significant Role in Cognitive Decline, Study Suggests

Effective dental hygiene practices may help to improve overall brain health, a new study published in Neurology indicates. The findings suggest that gum disease and tooth loss may be linked to brain shrinkage in the hippocampus, which is involved in memory and Alzheimer disease, according to the authors. They added that their research only shows an association and does not prove gum disease or tooth loss causes cognitive decline in Alzheimer disease.

“Tooth loss and gum disease, which is inflammation of the tissue around the teeth that can cause shrinkage of the gums and loosening of the teeth, are very common, so evaluating a potential link with dementia is incredibly important,” said study author Satoshi Yamaguchi, PhD, DDS, of Tohoku University in Sendai, Japan, in a press release. “Our study found that these conditions may play a role in the health of the brain area that controls thinking and memory, giving people another reason to take better care of their teeth.”

The study notes that not all risk factors for dementia have been determined, with only 40% of all cases attributable to known modifiable risk factors. Recently, tooth loss and periodontitis caused by oral bacterial infection have been suggested as risk factors for Alzheimer disease and related dementia, according to the investigators.

“Regarding oral risk factors, animal studies have confirmed that a reduced number of teeth and the associated reduced masticatory activity cause hippocampal degeneration, and that the chronic oral administration of periodontal bacteria induces neurodegeneration in the hippocampus of wild-type mice,” the authors wrote in the study. “Previous studies in humans have reported the relationship between 1) the number of teeth, whole-brain volume, and gray matter volume (GMV); 2) the number of teeth and left hippocampal volume in older adults with cognitive impairment; and 3) people with edentulism and right hippocampus atrophy. However, these were cross-sectional studies. Although a longitudinal analysis recently reported that treatment of periodontitis improved AD-related brain atrophy, a previous study stated that the severity of periodontitis and tooth loss are not associated with morphological changes in the brain.”

To evaluate the potential association, the researchers enrolled 172 people with an average age of 67 years who did not have memory problems at study outset. The participants were given dental exams and memory tests at the beginning of the analysis, as well as brain scans to measure hippocampus volume both at the beginning of the study and 4 years later.

The investigators checked for gum disease via periodontal probing depth and recorded the number of teeth at the start of the study. The findings indicated that the number of teeth and amount of gum disease was associated with changes to the brain’s left hippocampus, according to the study.

Mild gum disease and fewer teeth were associated with a faster rate of brain shrinkage in the left hippocampus, whereas severe gum disease and having more teeth was associated with a faster rate of brain shrinkage in the same area, the authors found. After adjusting for age, the findings show that among individuals with mild gum disease, the increased rate of brain shrinkage due to 1 less tooth was equivalent to approximately 1 year of brain aging. Conversely, for people with severe gum disease, the increase in brain shrinkage due to 1 more tooth was equivalent to 1.3 years of brain aging.

“These results highlight the importance of preserving the health of the teeth and not just retaining the teeth,” Yamaguchi said in the release. “The findings suggest that retaining teeth with severe gum disease is associated with brain atrophy. Controlling the progression of gum disease through regular dental visits is crucial, and teeth with severe gum disease may need to be extracted and replaced with appropriate prosthetic devices.”

Additional research will be needed with larger patient populations to evaluate the findings, according to the study authors.

Reference

Yamaguchi S, et al. Associations of Dental Health With the Progression of Hippocampal Atrophy in Community-Dwelling Individuals: The Ohasama Study. Neurology. Jul 2023. Accessed July 17, 2023. DOI: 10.1212/WNL.0000000000207579; DOI: 10.1212/WNL.0000000000207579

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Study links tooth loss to brain shrinkage

Gum disease and tooth loss may be linked to brain shrinkage in the hippocampus, a region that has significant ties to memory and Alzheimer’s disease, a group in Japan has reported.

 

Researchers led by Dr. Satoshi Yamaguchi, PhD, of Tohoku University in Sendai, Japan, studied longitudinal associations between the number of teeth present and hippocampal atrophy in a group of late middle-aged and older adult subjects. 

“Fewer teeth were associated with a faster rate of left hippocampal atrophy in patients with mild periodontitis, whereas having more teeth was associated with a faster rate of atrophy in those with severe periodontitis,” the group wrote. 

The study involved 172 people with an average age of 67 who did not have memory problems at the beginning of the study. Participants had dental exams and took memory tests in addition to undergoing brain magnetic resonance imaging to measure the volume of their hippocampus both at the beginning of the study and again four years later.

In addition, researchers counted the number of teeth for each participant and checked for gum disease by assessing periodontal probing depth, a measurement of the gum tissue.

After adjusting for age, the group reported that for people with mild gum disease, the increase in the rate of brain shrinkage due to one less tooth was equivalent to nearly one year of brain aging. Conversely, for people with severe gum disease, the increase in brain shrinkage due to one more missing tooth was equivalent to 1.3 years of brain aging.

"The findings suggest that retaining teeth with severe gum disease is associated with brain atrophy. Controlling the progression of gum disease through regular dental visits is crucial, and teeth with severe gum disease may need to be extracted and replaced with appropriate prosthetic devices," Yamaguchi said, in a news release.

Future studies are needed with larger groups of people, he noted. The study was published July 5 in Neurology.

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How Healthy Are Your Teeth And Gums? It Matters For Your Brain Health

Article courtesy of Dr. Joel Kahn, MD, who is a Clinical Professor of Medicine at Wayne State University School of Medicine, one of the world's top cardiologists, a best-selling author, lecturer, and a leading expert in plant-based nutrition and holistic care.

The scientific support for the connection between GI health and systemic health of the heart and brain is growing rapidly. The GI tract begins in the mouth and oral health as a factor in overall health is well supported. More data is needed.

Although tooth loss and periodontitis have been considered risk factors for Alzheimer's disease. A new study aimed to clarify an association between the number of teeth present (NTP) and hippocampal (region of the brain) atrophy dependent on the severity of periodontitis in a late middle-aged and older adult population.

 STUDY METHODS

This study included community-dwelling individuals aged ≥55 years who had no cognitive decline and had undergone brain magnetic resonance imaging (MRI) and oral and systemic data collection twice at 4-year intervals. Hippocampal brain volumes were obtained from MRIs by automated region-of-interest analysis.

The mean periodontal probing depth (mean PD) was used as a measure of periodontitis. Multiple regression analysis was performed with the annual symmetric percentage change (SPC) of the hippocampal volume as the dependent variable and including an interaction term between NTP and mean PD as the independent variable.

STUDY RESULTS

The data of 172 participants were analyzed. The qualitative interaction between NTP and mean PD was significant for the annual SPC in the left hippocampus.

The regression coefficient of the NTP on annual SPC in the left hippocampus region of the brain was negative at the high-level PD.

DISCUSSION

In a late middle-aged and older cohort, fewer teeth were associated with a faster rate of left hippocampal atrophy in patients with mild periodontitis, whereas having more teeth was associated with a faster rate of atrophy in those with severe periodontitis.

The importance of keeping teeth and gums healthy is imperative for optimal brain aging. Similar data for the importance of healthy teeth and gums for cardiovascular and sexual health has also been reported recently.

A lot of individuals are off track with routine dental cleanings since the pandemic and resuming regular cleanings and daily hygiene habits is recommended.

 

About the author: At his core, Dr. Joel Kahn believes that plant-based nutrition is the most powerful source of preventative medicine on the planet. Having practiced traditional cardiology since 1983, it was only after his own commitment to a plant-based vegan diet that Dr. Kahn truly began to delve into the realm of non-traditional diagnostic tools, prevention tactics, and nutrition-based recovery protocols. 

As with anything you read on the internet, this article should not be construed as medical advice; please talk to your doctor or primary care provider before changing your wellness routine. This article is not intended to provide a medical diagnosis, recommendation, treatment, or endorsement.

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Study warns of tooth enamel erosion due to fizzy drinks 

The potentially harmful effects of excessive consumption of carbonated drinks on dental health have been highlighted in a recent study published in the journal Nutrients, which also underscores the importance of understanding the impact of such consumption on dental health,

as it can adversely impact individuals' overall quality of life and self-esteem.

Additionally, dental treatments can be expensive, making prevention crucial.

The study emphasises the role of diet in dental health, particularly in issues like enamel degradation and dental caries. While other factors such as genetics, socioeconomic variables, oral hygiene, and lifestyle contribute to the development of dental caries, the consumption of low pH foods, like carbonated drinks, has been found to significantly contribute to enamel erosion.

The study reveals a substantial increase in dental problems during the Covid-19 pandemic, which coincided with a rise in carbonated drink consumption. Carbonated soft drinks lower the pH of saliva, causing it to fall below the healthy range for dentin enamel due to the presence of carbonic acid.

To reach their conclusions, the researchers conducted a comprehensive review of open-access and randomised control studies, both in vitro and in vivo, to assess the impact of carbonated soft drinks on dentin enamel.

After excluding studies that were not open-access, published in other languages, or categorised as reviews, case reports, editorials, or book chapters, a total of 19 studies were included in the review. These studies revealed a clear association between substantial consumption of carbonated soft drinks and an increased risk of dental erosion, structural disintegration of the tooth, and degradation of the mechanical and physical properties of the enamel.

Furthermore, the rougher texture of eroded surfaces helps facilitate bacterial adherence, leading to a higher risk of dental caries.

Dental erosion was most commonly observed near the upper arch of canines and incisors, while flawed oral hygiene methods and socioeconomic conditions were found to impact oral health.

The study also highlighted the influence of acid content and contact time on enamel erosion as  carbonated soft drinks contain carbonic, phosphoric, and citric acids. It shows that prolonged exposure to these acids can cause tooth sensitivity and eventual enamel erosion.

The mineral content of the drinks, including phosphate, fluoride, and calcium, was found to affect the erosive potential, with higher concentrations of these minerals resulting in lower enamel erosion.

Based on these findings, it is essential to raise awareness among the public, especially young individuals, about the risks associated with excessive consumption of carbonated soft drinks. Educating people about the impact of these drinks on dental health and promoting healthier food choices are crucial steps in mitigating the potential harm caused by carbonated drink consumption.

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Are 'living fillings' the future of teeth restoration? Enamel-growing organoids could open up regenerative dentistry

It’s one of life’s hard truths: Once tooth enamel is gone, you can’t get it back. And while tooth tech has come a long way since the days of wooden dentures, there’s no regrowing lost teeth.

But that may not be the case forever. In a new study published Aug. 14 in Development Cell, a research team led by scientists from the University of Washington School of Dentistry described how it used human stem cells to grow organoids, or 3D tissue cultures, that produce working enamel-producing ameloblasts. 

“This is a critical first step to our long-term goal to develop stem cell-based treatments to repair damaged teeth and regenerate those that are lost,” co-author, researcher and dentist Hai Zhang, Ph.D., said in a press release. 

To create the organoids, the researchers studied and then replicated the genetic program that leads fetal stem cells to grow into specialized enamel-producing cells. This involved a gene sequencing technique called single-cell combinatorial indexing RNA sequencing—sci-RNA-seq, for short—which shows which genes are active at different stages of cell development. 

After using sci-RNA-seq to see which genes were active in different developmental phases, the researchers used a program called Monocle to map the gene expression patterns that drive stem cells to differentiate into ameloblasts. This gave them a “blueprint” to help build ameloblasts.

The researchers then exposed the stem cells to chemicals that would promote gene expression in the same sequence identified by sci-RNA-seq. After some “trial and error,” as the researchers put it in the press release, they successfully coaxed the stem cells to become ameloblasts. In the course of doing so, they discovered a previously uncharacterized cell type: a subodontoblast, believed to be a precursor for another type of cell, an odontoblast, that’s necessary for tooth formation.  

 

Together, the different cell types could be induced to form organoids that resembled structures found in developing human teeth. These organoids secreted ameloblastin, amelogenin and enamelin, three proteins that form the basis of enamel. Under the right conditions, including a process called remineralization, these proteins could form into enamel. 

While dentist Arun Narang, who runs a private dental practice in Mississauga, Ontario, called the findings “intriguing,” as they could one day help many patients, he noted that there are plenty of questions around practical application.

“I’m still waiting to find out how the proteins from the organoids are placed on the teeth or how they will help those with declining enamel regrow it,” Narang said in an email to Fierce Biotech Research. “That is something we would need to wait and see about.” 

The scientists are working on ways to refine the process so the enamel becomes as durable as teeth. Once that’s accomplished, they could move to growing it in a laboratory and eventually use it to fill cavities—or, perhaps, “living fillings” that grow on their own, the researchers described in the press release. 

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“This may finally be ‘the Century of Living Fillings’ and human regenerative dentistry in general,” researcher and project lead Hannele Ruohola-Baker, Ph.D., said in the release.

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Cleaning your teeth with interdental brushes in combination with toothpaste may cause approximal dentin abrasion, according to an in vitro study that was recently published in the International Journal of Dental Hygiene.

However, interdental brushing with chlorhexidine gel or a povidone-iodine gargle showed no measurable dentin loss, the authors wrote. It is believed to be the first study that shows that when toothpastes are used with interdental brushes, they have the potential to cause root damage, the authors wrote.

“Interdental brushes should not be used neither under direct toothpaste application nor without rinsing immediately after brushing, since remaining abrasives of the toothpaste in the saliva may lead to accentuated abrasion, wrote the authors, led by Dr. Patrick Schmidlin of the Clinic of Conservative and Preventive Dentistry at the University of Zurich in Switzerland (Int J Dent Hyg, September 3, 2023).

Recently, patients with bizarre proximal and lingual-cervical lesions caused by unusual interdental cleaning habits have made their use a relevant part of daily dental practice. For example, a 66-year-old healthy, nonsmoking man under periodontal therapy presented at the dental office with buccal and interproximal tooth substance loss. The tooth loss was caused by regular interdental brushing with medium- to high-abrasive toothpastes three times daily.

To evaluate dentin abrasion associated with the use of interdental brushes with various toothpastes and gels, a novel in vitro toothbrushing model was developed. Using dentin samples, the model imitated a simplified interdental space with an interdental brush. Brushing, which was 7,200 strokes per hour, was performed with artificial saliva, a povidone-iodine solution, slurries of chlorhexidine and fluoride gels, and toothpastes with relative dentin abrasiveness values ranging from 29 to 100, according to the study.

Though chlorhexidine and povidone-iodine showed no measurable dentin loss, toothpastes resulted in measurable linear surface damage in relation to relative dentin abrasiveness values and ranged from 12.6 μm to 26.5 μm (p < 0.001). The higher the dentin abrasiveness values were in toothpaste, the higher the surface damage was, the authors wrote. Abrasive ingredients in toothpastes can affect the roughness of interdental brushes, which may be linked to their intrinsic relative dentin abrasiveness values, they wrote.

The model had limitations. Since no remineralization phases were included in the study, it represents a very basic, worst-case scenario, the authors wrote. Since the removal of eroded dentin depends on the hardness and stiffness of a brush and the relative dentin abrasivity value of toothpaste, these factors should be addressed for interdental brush designs in future studies, they wrote.

Therefore, patients should be carefully instructed on the use of interdental cleaning products, Schmidlin et al wrote. 

“Any over- and misuse, which applies especially to the combination with abrasive toothpastes, should be avoided,” they wrote. 

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The link between orofacial myofunctional disorders and dental health

How many rabbits have you seen with crooked teeth? How about bears or dogs? Why are humans the only mammals with crooked teeth?

An orofacial myofunctional disorder, or OMD, describes abnormal lip, jaw, or tongue positions during rest, swallowing, or speech. There are many distinct points at which a child or adult’s system may experience a breakdown, leading to subsequent events known as craniofacial sequences. Allowing these events to persist without intervention may ultimately lead to an OMD.

An OMD can be caused by airway obstruction (such as sinus infections, enlarged tonsils, allergies), structural dysmorphology (such as craniofacial differences, restricted oral frenula), and/or idiosyncratic behaviors (such as sucking or chewing habits).

Human teeth get crooked. Palatal expanders and braces may fix the problem, but how do they become crooked in the first place? At rest, your tongue tip should be on the roof of your mouth, also called the alveolar ridge; your lips should be closed, and there should be about 1 millimeter of space between your back molars. There are three reasons why a child’s tongue may lie at the bottom of the mouth: to maximize the airway, soft tissue obstruction (for example, a lip or tongue tie), or there were airway or soft tissue obstructions that were fixed, but the child is continuing the habit. There are many more reasons why an adult’s tongue may lie at the bottom of the mouth, including the aforementioned reasons.

A palatal expander is used to widen a narrow palate. When the tongue tip lies on the alveolar ridge, it counteracts the pressure of the cheeks, which would otherwise push the upper jaw in, narrow the palate, and cause dental issues (like crooked teeth). Thus, the tongue tip is our body’s natural palatal expander. Neglecting to utilize our natural mechanism results in a narrowed palate, leading to complications such as dental misalignments. Employing our tongue tip comes at no cost and is a more economical approach compared to using a palatal expander! Additionally, the lips act as natural braces for the teeth. Again, this is more economical than braces.

As I mentioned, OMDs are caused by a sequence of events. Imagine a row of dominoes being knocked down, one right after another. If we don’t stop them, they will continue to fall. Let’s take a look at some examples.

Consider a child who develops airway obstruction secondary to allergies. This obstruction causes the child to open their jaw to maximize the airway. The jaw opening causes the tongue’s position to lower and move forward. Because the tongue tip is no longer lying on the roof of the mouth, the hard palate narrows. When the hard palate narrows, the teeth no longer have enough room, causing dental changes, including malocclusions. It doesn’t stop here, though. Due to the shifted tongue posture and narrower palate, articulation will be affected. Likely, this child will have an articulation disorder. Mouth breathing due to sinus tissue swelling (rhinitis) and impaired nose function can lead to sleep-disordered breathing.

Next, let’s consider a child with a low resting posture due to consistent thumb sucking. The tongue descends and moves forward, initiating the cycle again. In this case, thumb-sucking can transition into tongue-thrusting. Because the tongue remains under the thumb for extended periods, once the thumb is removed from the mouth, the tongue continues the back-and-forth motion. This child will end up with bottom teeth leaning medially and upper teeth leaning distally, resulting in an open bite.

Now, let’s examine an adult who is morbidly obese. Daily activities are a struggle, leading the adult to breathe through their mouth all day. Consequently, the tongue falls low, triggering the domino effect once again.

Lastly, let’s consider two different adults who never had allergies or any of the aforementioned issues. One receives dentures, and the other gets a bite plate. What happens to the resting tongue posture? It can no longer be at the alveolar ridge because the appliances are slippery, causing the tongue to rest at the bottom of the mouth. Consequently, the jaw must open wider to accommodate the tongue. Inefficient breathing leads to mouth breathing, which likely occurs during both day and night. The domino effect is set in motion.

Recall the initial question about why humans are the only mammals with crooked teeth. Simply put, we are the only mammals altering our eating habits, breathing patterns, and sleep positions. By addressing these areas, we can prevent the domino effect of misaligned teeth, sleep-disordered breathing, articulation disorders, and more.

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