BMP9 regulates tooth root development

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Caption

(A) Construction of the Bmp9-KO mice. (B) Relative expression of Bmp9 in the liver of 8-week-old wild-type (WT) littermates and Bmp9-KO mice by quantitative PCR in vitro (n ≥ 3). (C) Western blots of BMP9 and β-actin in the liver of 8-week-old WT littermates and Bmp9-KO mice (n = 6). (D) Immunohistochemical staining of BMP9 on sections of mandibular first molars from WT littermates and Bmp9-KO mice at 2 weeks and 4 weeks old (n = 7). The boxes shown are insets at a lower magnification. Am, ameloblasts; Od, odontoblasts; D, dentin. (E) Quantitative analysis of BMP9 expression. Scale bars = 200 μm.

Credit

Chang Liu, Hongyan Yuan, Jindie Huang, Shidian Ran, Xiaorui Wei, Xingrui Yan, Linyu Xue, Tong-Chuan He, Yuxin Zhang, Mengqin Gu, Si Wu, Fugui Zhang, Wenping Luo, Hongmei Zhangng

The interaction between Hertwig's epithelial root sheath (HERS) and surrounding mesenchymal cells is crucial for root dentin formation. HERS influences tooth root development and odontoblast differentiation; however, further research is needed to elucidate its regulatory mechanisms.

A new study published in the Genes & Diseases journal by researchers from the Affiliated Hospital of Stomatology of Chongqing Medical University, the Chongqing Municipal Health Commission Key Laboratory of Oral Biomedical Engineering, Southwest University, and the University of Chicago Medical Center provides mechanistic insights into how Bmp9 signaling impacts tooth root development.

The authors have previously shown that Bmp9 is crucial for tooth and alveolar bone formation, and in this study report that Bmp9 signaling modulates tooth root development by regulating the development of odontoblasts and HERS.

The authors generated Bmp9-KO mice and, upon comparison with their wild-type (WT) mice, observed that BMP9 plays a critical role in molar root development, dentin mineralization, and root elongation during early odontogenesis. Knockdown of Bmp9 inhibited odontoblast differentiation and also impacted the normal development of the mandibular first molars, as evidenced by shorter molar roots, wider apical foramen, and reduced dentin thickness. Bmp9 ablation disrupted odontoblast polarization, affecting their secretory capacity and weakening DSPP secretion, resulting in delayed dentin mineralization, increased collagen type I deposition, and reduced root length.

Furthermore, knockdown of Bmp9 inhibited cell proliferation within the HERS, thereby affecting HERS elongation and bending, and formation of the root apical foramen, which resulted in shorter roots, thinner dentin, and an unclosed apical foramen in Bmp9-KO mandibular first molars. Additional experiments involving Bmp9 overexpression and knockdown in primary HERS cells showed that “Bmp9 signaling modulates both HERS cell proliferation and intercellular junctions, thereby contributing to the proper development of tooth roots.” 

Comparative transcriptomic profiling and pathway analysis (GO and KEGG) revealed that Bmp9 maintains HERS cell proliferation, junction homeostasis, and drives root morphogenesis by integrating a multidimensional regulatory network involving TGF-β and Wnt signaling and cell-cell connections.

In conclusion, this study is the first to report that BMP9 signaling influences root odontoblast function by regulating cell proliferation and intercellular junctions within HERS, thereby affecting the overall developmental trajectory of molar roots. The authors highlight the need for further research to identify specific binding sites and the mechanism of action of Bmp9 in regulating HERS proliferation and intercellular connectivity integrity.

Reference

Title of the original paper: Bmp9 modulates cell proliferation and intercellular junctions in HERS during tooth root development

Journal: Genes & Diseases

Genes & Diseases is a journal for molecular and translational medicine. The journal primarily focuses on publishing investigations on the molecular bases and experimental therapeutics of human diseases. Publication formats include full length research article, review article, short communication, correspondence, perspectives, commentary, views on news, and research watch

DOI: https://doi.org/10.1016/j.gendis.2025.101777

For young adults, the color of their teeth is important

 

Peer-Reviewed Publication

University of Gothenburg

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image: 

Laura Ståhl, Sahlgrenska Academy at the University of Gothenburg.

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Credit: Phot: Margareta G. Kubista

White teeth are highly valued by young adults. But an even tooth color is considered to be of even higher importance. A study from the University of Gothenburg, one of the first of its kind, shows that many people with a deviant color on a part of a tooth would like treatment.

The aim of the study, published in the journal Acta Odontologica Scandinavica, was to investigate young individuals' esthetic perception of the color on the visible surfaces of the upper front teeth, in themselves and in others.

The results are based on an online survey, launched via social media and targeted at individuals aged 18-30 years in Sweden. There were 2,082 participants, 55% of whom were women. The average age was 25 years.

Participants were asked to rate how satisfied they were with their own tooth color and how they perceived unevenness of tooth color (deviant color on a part of a tooth, spots). The results showed that 77% of participants were satisfied with their tooth color, with no major differences between gender and age. In contrast, those who perceive having a deviant color on a part of a tooth were less satisfied with their tooth color.

The color of teeth is noticed

Participants were also shown photos of different teeth with and without deviant color on a part of the enamel of the front teeth and then asked to rate esthetic impression. When participants looked at the photos and found the tooth color unacceptable, 90% of them cited the color deviation as a cause, with shade and extent also playing a role.

White teeth were revealed to be very popular. On a scale of 0 to 10, with 0 being unimportant and 10 being very important, white teeth scored an average of 7.25. Even higher scores were given to an even tooth color, with an average score of 8.

Laura Ståhl is a PhD student at the Institute of Odontology at the University of Gothenburg, a Dental Professional in the Public Dental Service in Gothenburg and the study's first author:

“What we found is that the participants in the study notice uneven tooth color, and that it is something that is perceived negatively. We also observed that those who are more satisfied with their own tooth color placed more importance on the color of teeth, both their own and that of others.”

“It is important to understand how young people view their teeth, to listen to them and take their concerns seriously. Oral health is a broad concept—it is not only about having a healthy mouth, but also about being able to smile, laugh, and show self-confidence in every expression.” says Laura Ståhl.

Color correction: yes please

In the study, a higher proportion of women (22%) than men (13%) had experience with teeth whitening. Of those who reported having a deviant color on a part of a tooth, 9 percent had color corrective treatment. Another 52% were interested in having it.

The study is also authored by Nina Sabel, Associate Professor at the Institute of Odontology at the University of Gothenburg, Senior Dentist in Pediatric Dentistry, and with knowledge of esthetic treatment of uneven tooth color:

“Teeth are seen as an important part of the appearance, and some young people are troubled by having a deviant colour on part of a tooth. Teeth whitening or other treatments will not give you a total makeover, but can lead to improvements if done correctly,” she says.
“Dentistry does not own the issue of teeth whitening, which I wish it did. Different color deviations have different causes, requiring different types of treatment. In addition, dental professionals are knowledgeable about the risks and can prevent injury to gums, for example. A tip to minimizing side effects is to ensure that the bleaching is done in a controlled manner with a low concentration of hydrogen peroxide. It is also important not to over-bleach, because once your teeth have turned neon white, you cannot go back,” says Nina Sabel.

Fact box:

Participants were exposed to images of three dental conditions with deviant color on a part of the enamel:

Molar-Incisor-Hypomineralization (MIH) - a condition of unclear cause that results in more porous enamel and increased sensitivity of some teeth. Appearing as white, yellow, or brownish color deviations of the enamel of molars, and sometimes also on front teeth.

Dental Fluorosis - a condition caused by the overconsumption of fluoride early in life that results in visible color deviation of the enamel. Elevated fluoride intake may be due to high levels of fluoride in drinking water, for example from your own well. Generally seen as white to brown deviant color on a part of the enamel.

White Spot Lesions - a condition also known as enamel demineralization, seen as white areas in the enamel. Occurring in cases of poor oral hygiene usually at the gum line and can occur, for example, as a complication of orthodontic treatment with fixed braces, mainly around the braces.

Source: University of Gothenburg

 

 

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Journal

Acta Odontologica Scandinavica

DOI

10.2340/aos.v84.44231 

Oral microbes linked to increased risk of pancreatic cancer

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Twenty-seven species of bacteria and fungi among the hundreds that live in people’s mouths have been collectively tied to a 3.5 times greater risk of developing pancreatic cancer, a study led by NYU Langone Health and its Perlmutter Cancer Center shows.

Experts have long observed that those with poor oral health are more vulnerable to pancreatic cancer than those with healthier mouths. More recently, scientists have uncovered a mechanism that could help explain this connection, finding that bacteria can travel through swallowed saliva into the pancreas, an organ that helps with digestion. However, precisely which species may contribute to the condition had until now remained unclear.

Publishing online Sept. 18 in JAMA Oncology, the new analysis assessed the genetic makeup of microbes collected from the saliva of 122,000 healthy men and women.

“Our findings provide new insight into the relationship between the oral microbiome and pancreatic cancer,” said study lead author Yixuan Meng, PhD, a postdoctoral fellow in the Department of Population Health at NYU Grossman School of Medicine.

The oral microbiome, the diverse community of bacteria and fungi that inhabit the mouth, is increasingly being studied for its potential role in human health.

Last year, the same team of scientists uncovered a link between certain oral bacteria and a heightened risk of developing head and neck squamous cell carcinoma, a group of cancers that arise in the mouth and throat. The researchers had also conducted a small study in 2016 that tied microbes living in the mouth to pancreatic cancer, but could not identify precise bacterial species.

Their latest report is the largest and most detailed analysis of its kind to date, says Meng. It is also the first to show that oral fungi — namely a type of yeast called Candida that naturally lives on the skin and throughout the body — may play a role in pancreatic cancer. The researchers also identified these oral Candida species in patients’ pancreatic tumors.

For the study, the team assessed data from two ongoing investigations tracking Americans from across the country to better understand how diet, lifestyle, medical history, and many other factors are involved in cancer. The data were gathered for the American Cancer Society Cancer Prevention Study II and the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.

Shortly after enrolling, participants rinsed with mouthwash, providing saliva samples that preserved the numbers and species of microbes for testing. Researchers then followed up for roughly nine years on average to record any presence of tumors.

In the current study, the investigators analyzed bacterial and fungal DNA from the spit samples. Then, they identified 445 patients who were diagnosed with pancreatic cancer and compared the DNA of their microbes with that of another 445 randomly selected study subjects who had remained cancer free. The team made sure to account for factors known to play a role in developing the condition, such as age, race, and how often subjects smoked cigarettes.

The findings identified 24 species of bacteria and fungi that individually either raised or lowered pancreatic cancer risk. Another three kinds of bacteria tied to the cancer were already known to contribute to periodontal disease, a serious gum infection that can eat away at the jawbone and the soft tissues surrounding teeth.

Altogether, the entire group of microbes boosted participants’ chances of developing the cancer by more than threefold.

In addition, by assessing the makeup of each participant’s oral microbiome, the scientists for the first time developed a tool that could estimate their cancer risk.

“By profiling bacterial and fungal populations in the mouth, oncologists may be able to flag those most in need of pancreatic cancer screening,” said study co-senior author Jiyoung Ahn, a professor in the Departments of Population Health and Medicine at NYU Grossman School of Medicine.

Ahn, who is also the associate director for population sciences at Perlmutter Cancer Center, notes that there are currently few effective screening methods for the disease, which is among the deadliest forms of cancer.

“It is clearer than ever that brushing and flossing your teeth may not only help prevent periodontal disease but may also protect against cancer,” said study co-senior author Richard Hayes, DDS, MPH, PhD, a professor in the Department of Population Health at NYU Grossman School of Medicine.

Hayes, who is also a member of Perlmutter Cancer Center, emphasizes that the study was designed to identify correlations between disease risk and certain microbes in the mouth, but not to establish a direct cause-and-effect link. That will require further investigation.

The research team next plans to explore whether oral viruses could contribute to cancer and how the mouth’s microbiome may affect patients’ chances of survival, adds Hayes.

Funding for the study was provided by National Institutes of Health grants P30CA016087, P20CA252728, R01LM014085, R01CA159036, and U01CA250186.

Along with Meng, Hayes, and Ahn, other NYU Langone researchers involved in the study are Feng Wu, PhD; Soyoung Kwak, PhD; Chan Wang, PhD; Tamas Gonda, MD; Paul Oberstein, MD; and Huilin Li, PhD.

Other study co-investigators include Mykhaylo Usyk, PhD, at Albert Einstein College of Medicine in New York City; Neal Freedman, PhD, and Wen-Yi Huang, PhD, at the National Cancer Institute in Rockville, Maryland; and Caroline Um, PhD, at the American Cancer Society in Atlanta.

About NYU Langone Health
NYU Langone Health is a fully integrated health system that consistently achieves the best patient outcomes through a rigorous focus on quality that has resulted in some of the lowest mortality rates in the nation. Vizient, Inc. has ranked NYU Langone No. 1 out of 118 comprehensive academic medical centers across the nation for four years in a row, and U.S. News & World Report recently ranked four of its clinical specialties number one in the nation. NYU Langone offers a comprehensive range of medical services with one high standard of care across seven inpatient locations, its Perlmutter Cancer Center, and more than 320 outpatient locations in the New York area and Florida. With $14.2 billion in revenue this year, the system also includes two tuition-free medical schools, in Manhattan and on Long Island, and a vast research enterprise.

Media Inquiries
Shira Polan
Phone: 212-404-4279
Shira.Polan@NYULangone.org

 

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Journal

JAMA Oncology

DOI

10.1001/jamaoncol.2025.3377 

One in three young adults skip the dentist, and that’s a problem

Regular dental checkups are vital for overall health. Yet dental care in the United States is still excluded from medical health insurance coverage and usually not integrated with public health initiatives that promote preventative care. A new study from a researcher at Tufts University School of Dental Medicine found that nearly one in three young adults skipped visits to the dentist in the past year—and pointed to wider health and access problems that could affect the nation’s future workforce and health systems.     

Published recently in Frontiers in Oral Health, the study is the first to compare people’s social and economic circumstances, access to dental care, and self-reported health challenges across different ages. The study builds on past research about cost and access barriers to dental care, but it provides new insights by showing that young adults are especially likely to miss out on care—and that factors like mental health and housing problems also play a role. 

“Young adults, aged 18 to 35 years old, were the most likely to report not having visited a dentist within the past 12 months,” says Yau-Hua Yu, the study’s author and an associate professor of periodontology at the School of Dental Medicine. “This is very troubling."

Her earlier research suggested that poor oral health is linked to shortened life expectancy and other negative health outcomes.  

For this study, Yu analyzed health, demographic, and dental-care data from nearly 128,000 adults in the National Institutes of Health’s All of Us program, one of the world’s largest biomedical databases. Yu used the data to examine how physical challenges and mental health issues reported by individuals from different socioeconomic backgrounds varied depending on three factors: whether they had visited a dentist in the past year, their income level, and their age. 

“Across all ages, people generally managed to see a doctor,” says Yu. “But those who skipped dental care most often pointed to cost and lack of insurance coverage.” She says this finding reinforces the need to address the persistent policy gap in dental coverage, especially for those not covered by employer-based insurance or public programs.  

Young adults who missed dental visits were also more likely to skip medical care, struggle with copays, rely on emergency care, and report poor mental health or memory problems. Yu found that this group of study participants were more likely to be renters, uninsured, and racially diverse—and that unstable housing added financial and emotional strain.  

The study’s age-based analysis revealed other important generational contrasts. While adults aged 66 years or older were more likely to have insurance and own a home, they also reported more disabilities. Individuals who reported difficulty walking, bathing, running errands, or concentrating were more likely to skip dental care, particularly among these older adults.  

“Our findings show the urgent need to integrate dental care into overall health care,” Yu says. “They also suggest that interventions must be tailored not only to income, but to life stage and cumulative disadvantage. The desperate need to bring routine preventative dental care to younger adults—who will be our prime source for societal productivity—should not be ignored.”  

This may include expanding public dental insurance and integrating oral health equity goals into public health surveillance and primary care frameworks, Yu says. 

For older adults, barriers like transportation and mobility point to the need for home-based or mobile dental programs. 

For young adults, Yu adds that community organizations and faith-based health systems could be key partners in expanding access, as they already offer models of integrated affordable dental care.  

“When dental care is rooted in trusted community spaces, it feels more familiar and supportive,” she says. “That lowers the barriers of fear, inconvenience, and cost uncertainty that may keep some young adults away—and it helps them shift from waiting until there’s an emergency to hopefully seeking regular, preventive care.” 

Journal

Frontiers in Oral Health

DOI

10.3389/froh.2025.1619983 

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Mediterranean diet could reduce gum disease

 

People following a diet close to the Mediterranean diet are more likely to have better gum health, with potentially lower amounts of gum disease and inflammation. 

Findings from a King’s College London study indicate that people not following a Mediterranean – style diet tended to have more severe gum disease, especially if they consumed red meat frequently.  

In these patients, the researchers observed higher levels of circulating inflammatory markers, such as Interleukin-6 (IL-6) and C-reactive protein (CRP).  

However, patients whose diets were rich in plant-based food which are typical of a Mediterranean diet, such as legumes, vegetables, fruits and olive oil, showed lower levels of various inflammatory markers. 

The research, published today in the Journal of Periodontology, evaluated 200 hospital patients enrolled in the King’s College London Oral, Dental and Craniofacial Biobank by performing dental exams, taking blood samples, and asking them about their diets through questionnaires. 

The Mediterranean diet is known for its emphasis on fruits, vegetables, whole grains, and healthy fats. It has been associated with a lower risk of developing major diseases, including cardiovascular diseases, neurodegenerative disorders, and certain cancers. 

There is substantial evidence showing that diet might play a role on human health by affecting the immune system and moderating inflammation. This depends on the composition of molecules in the diet, which include macronutrients, micronutrients and phytochemicals. Plant-based diets can contain more of these molecules which can lead to lower inflammation. 

Dr Giuseppe Mainas, first author of the study and a postdoctoral researcher at King’s College London, said: “Our findings suggest that a balanced, Mediterranean-type diet could potentially reduce gum disease and systemic inflammation.  

“We observed that there may be a connection between periodontal disease severity, diet, and inflammation. These aspects should be holistically considered when assessing the treatment for periodontitis in patients. Our research offers an important starting point that can lead to more research to better understand the relationship between foods intake and gum disease.” 

Professor Luigi Nibali, lead author and a Professor of Periodontology from King’s College London said: “There is emerging evidence about the role that a balanced diet might have in maintaining a periodontal healthy status. Our research shows the potential effect that a nutrient-dense, plant-rich diet could play in improving the nation’s gum health. Nevertheless, more investigation is needed to develop personalised approaches to help people manage their gum health.” 

Teens who lose teeth to decay and injury nearly twice as likely to be bullied

 

Adolescents who lose teeth due to decay or trauma are 42 percent more likely to be bullied, according to new collaborative research from the University of Sydney and the University of Melbourne. 

 

Published in JDR Clinical & Translational Research, the paper analysed data from 4400 children in The Longitudinal Study of Australian Children, following their health outcomes from childhood (eight- to nine-year-olds) to adolescence (14- to 15-year-olds). 

 

Senior author Associate Professor Ankur Singh, Chair of Lifespan and Oral Health at the School of Dentistryand member of the Charles Perkins Centre said: “Tooth loss isn’t only a dental issue, it’s a social one too. For teenagers, it can have significant psychological impacts at a crucial time in their development.”

 

Around 10 percent of children in Australia have lost teeth through decay or injury, with children from lower socioeconomic backgrounds, as well as rural or remote areas, the most likely to have experienced tooth loss. 

 

“Poor oral health impacts nutrition, sleep, self-confidence and overall wellbeing, as well as being linked to heart disease and high blood pressure. To address these issues, the government needs to invest in prevention programs tackling oral and improve equitable access to dental care, especially in rural and remote areas and in low-income communities,” Associate Professor Singh said. 

 

Recent research suggests that bullying is widespread, with 70 percent of children aged 12-13 experiencing at least one incident of bullying a year. 

 

Within Australia, 28 percent of year eight students (aged 12 to 13) said they were bullied every month, with 8 percent saying they were bullied every week. 

 

First author Yuxi Li, PhD candidate at the University of Melbourne, said: “Anyone who has been bullied at school can testify to what an awful experience it can be. 

 

“As well poor psychological outcomes, bullying can also have adverse physical outcomes such as overweight and obesity. 

 

“We hope that this study will raise awareness about the link between oral health, bullying and young people’s overall wellbeing.”

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Journal

JDR Clinical & Translational Research

DOI

10.1177/23800844251357941