Abstract | Dental and Oral Health

Frequent cannabis use can lead to cavities, severe tooth loss, according to study

2025-02-13 - 2025-02

Clonan, who joined the faculty in spring 2024 as a clinical assistant professor in the Department of Pediatric and Community Dentistry, spotted the association between cannabis and tooth decay while completing her Dental Public Health Residency Program at Jacobi Medical Center in Bronx, New York. As part of the intake questionnaire at the public clinic where she worked, patients would often answer "no" when asked if they smoked, Clonan said. However, when she gave them home instructions following a tooth extraction such as, "no fried foods and no smoking," an important truth often would be revealed.
"They'd tell me, 'Well, I do smoke cannabis,'" she said.
Study looks at frequent cannabis smokers
To explore the possible connection, Clonan, who is also a consultant for the ADA, used a cross-sectional study analyzing data obtained from 5,656 adults ages 18-59 who participated in the National Health and Nutrition Examination Survey (NHANES), sponsored by the Centers for Disease Control and Prevention (CDC) between 2015 and 2018.
She discovered that people who reported smoking cannabis at least once a month for more than a year had a 17% higher chance of having untreated coronal caries (cavities), 55% higher odds of root surface caries and 41% higher odds of severe tooth loss compared with patients who did not smoke marijuana after controlling for age, sex, race or ethnicity, education, income or alcohol consumption.
"The surveys only focused on smoking cannabis, not other use such as edibles," Clonan said. "When you smoke cannabis, you're literally putting fire near your mouth, which is never good. It causes dry mouth, which can lead to tooth decay. Saliva protects you from dental caries."
Two other factors may contribute to cavities and tooth loss-the high-fat snacks, sugary foods and drinks people typically consume when they use cannabis and poor brushing habits while under the influence, she said.
Little research in this area
The effect of cannabis use on oral health has been on Clonan's radar for a while, she said, since numerous states, including New York, have legalized marijuana, and recreational use has skyrocketed.
"I saw a gap in the dental research compared with the medical field," she said, "so I decided to pursue this study."
All the information was self-reported, so Clonan suspects FRC use is higher than the surveys reveal.
"Someone in New York might be more forthcoming compared to someone in Alabama who might worry about who is looking at the survey," she said.
The average age of the study's respondents was 39. Clonan noted, however, that FRC use was reported by respondents across all ages, races and socioeconomic levels.
These findings reflect a national trend, Clonan added.
Cannabis use in adults 65 and older jumped by 75% over a three-year period, according to a recent report in the Journal of the Medical Association. Meanwhile, according to a 2023 study by the National Institute on Drug Abuse, the percentage of young

Stronger, safer, smarter: Pioneering Zinc-based dissolvable implants for bone repair

2025-02-12 - 2025-02

Surgeons routinely use stainless steel or titanium, which stay in the body forever, can cause discomfort and may require follow-up surgeries.
A new zinc alloy, designed by Monash biomedical engineers, could solve these problems by being mechanically strong but gentle enough to degrade safely over time while supporting optimal healing.
A study published today in Nature shows the research team's innovative approach to making the zinc alloy as strong as permanent steel implants and more durable than other biodegradable options like magnesium-based implants.
Lead researcher, Professor Jian-feng Nie, from the Department of Materials Science and Engineering, said the innovative material had the potential to transform orthopaedic care by reducing complications, minimising the need for additional surgeries, and offering a sustainable alternative to permanent metallic implants.
"Our zinc alloy material could revolutionise orthopaedic care -- opening the door to safer, smaller implants that not only enhance patient comfort but also promote better healing outcomes by minimising disruption to surrounding tissues," Professor Nie said.
"An implant that never disappears will always be a risk to the patient. On the other hand, one that degrades too fast won't allow adequate time for the bones to heal. With our zinc alloy material, we can achieve the optimal balance between strength and controlled degradation of the implant to promote better healing."
The research shows that by engineering the size and orientation of the material's grains, the zinc alloy can bend and adapt in unique ways to accommodate the shapes of its neighbouring tissues.
"This made it not only stronger but more flexible, offering a game-changing alternative for orthopaedics," Professor Nie said.
The research is paving the way for a new start-up to be launched out of Monash University with a focus on developing next-generation biodegradable implants.

Scientists identify a new cancer immunotherapy target: Dysfunctional B cells

2025-02-19 - 2025-02

University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center scientists have discovered a novel subset of cancer-fighting immune cells that reside outside of their normal neighborhood -- known as the tertiary lymphoid structure -- where they become frustratingly dysfunctional when in close contact with tumors.
Described today in the journal Science Translational Medicine, the finding gives oncologists a new target for developing immunotherapies: double negative memory B cells, so-called because they are negative for two markers found on the surface of their more common brethren. They may also be a useful diagnostic marker when creating treatment plans.
"The responsiveness of B cells is an important part of whether a patient with cancer does well or not," said senior author Tullia Bruno, Ph.D., assistant professor of immunology at Pitt and a member of the Cancer Immunology and Immunotherapy Program and Tumor Microenvironment Center at UPMC Hillman. "By better understanding different types of B cells and their location, we can aim to reinvigorate them and unleash their anti-tumor potential."
B cells are white blood cells, produced in the bone marrow, that neutralize pathogens -- such as bacteria, viruses and cancer cells -- and tag them for removal from the body. Memory B cells are particularly long-lived and "remember" pathogens, priming the immune system to respond quickly if it encounters the pathogen again. When someone has cancer or a chronic infection, their body may form tertiary lymphoid structures near or within the cancer. The structures contain immune cells -- predominantly B cells -- and patients with the structures tend to have better outcomes.
While doing her graduate work in Pitt's Program in Microbiology and Immunology, co-lead author Ayana Ruffin, Ph.D., now a postdoctoral research fellow at Emory University, observed that memory B cells were abundant in the blood of head and neck cancer patients -- particularly those doing well. Curious, she pored over existing research and found that, while double negative memory B cells were well-characterized in chronic infection and autoimmune studies, little was known about their role in cancer.
She turned from blood to tumor samples and found double negative memory B cells there as well -- but they were more dysfunctional, displaying features of exhaustion. Exhaustion is something cancer immunologists have been focused on with T cells -- immune cells that destroy pathogens, such as cancer. But Ruffin was one of the first to observe this exhaustion in memory B cells in and near tumors, outside of the tertiary lymphoid structure.
"Historically, B cells have largely been ignored in the cancer research field, with scientists instead favoring research on 'killer' T cells," said co-lead author Allison Casey, Ph.D. candidate in Pitt's Molecular Genetics and Developmental Biology graduate program who took over the research when Ruffin graduated. "But B cells are really unique -- they're like the cool person at school who talks to everyone. They can use antibodies to neutralize pathogens and engage other immune cells. They educate T cells so they know to destroy cancer or infections."
Casey and the research team are now exploring existing cancer immunotherapies -- which are mostly aimed at helping T cells fight cancer -- to see if there are ways to modify them to also boost memory B cells. They're also investigating B cell therapies used in autoimmune diseases to see if they can be leveraged to fight cancer.
"This is a really good example of when a graduate student comes to you with an awesome idea and runs with it -- she breaks new ground in the field," Bruno said. "This research is a testament to what happens when students are encouraged to think creatively."

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Frequent cannabis use can lead to cavities, severe tooth loss, according to study

Stronger, safer, smarter: Pioneering Zinc-based dissolvable implants for bone repair

Scientists identify a new cancer immunotherapy target: Dysfunctional B cells