Local exhaust ventilation to control dental aerosols and droplets

Dental procedures produce aerosols which contain oral microbes, creating potential for infectious disease transmission. This study, “Local Exhaust Ventilation to Control Dental Aerosols and Droplets” published in the Journal of Dental Research (JDR), investigated the effect of a Local Exhaust Ventilation (LEV) device on aerosols and droplets produced during dental procedures. These devices are designed to be placed over the patient’s mouth to capture aerosols and droplets at the source. 

Researchers at Newcastle University, England, conducted experiments on dental mannequins. Ten-minute crown preparations were performed with an air-turbine handpiece in a large open plan clinic, and full mouth ultrasonic scaling was performed for ten minutes in a single dental surgery. Fluorescein was added to instrument irrigation reservoirs as a tracer. In both settings, Optical Particle Counters (OPCs) were used to measure aerosol particles between 0.3 – 10.0 μm and liquid cyclone air samplers were used to capture aerosolised fluorescein tracer. An LEV device with High Efficiency Particulate Air (HEPA) filtration and a flow rate of 5,000 L/min was tested during the experiments. 

 

The results show that using LEV reduced the dispersion of aerosols from the air turbine handpiece by 90% within 0.5 m, and this was 99% for the ultrasonic scaler. The settling of larger droplets was also measured for the air-turbine, and this was reduced by 95% within 0.5 m when LEV was used.

 

"This study shows that the effect of LEV was substantially greater than suction alone for the air-turbine and was similar to the effect of suction for the ultrasonic scaler,” said IADR President Eric Reynolds, The University of Melbourne, Australia. “While no mitigation measure alone will completely eliminate risk, LEV appears to be a useful approach, which in addition to other measures, substantially reduces dispersion of aerosols, and therefore risk of exposure to pathogens."

Baby teeth may one day help identify kids at risk for mental disorders later in life

Peer-Reviewed Publication

The thickness of growth marks in primary (or “baby”) teeth may help identify children at risk for depression and other mental health disorders later in life, according to a groundbreaking investigation led by researchers at Massachusetts General Hospital (MGH) and published in JAMA Network Open. The results of this study could one day lead to the development of a much-needed tool for identifying children who have been exposed to early-life adversity, which is a risk factor for psychological problems, allowing them to be monitored and guided towards preventive treatments, if necessary.

The origin of this study traces back several years, when senior author Erin C. Dunn, ScD, MPH, learned about work in the field of anthropology that could help solve a longstanding problem in her own research. Dunn is a social and psychiatric epidemiologist and an investigator in MGH’s Psychiatric and Neurodevelopmental Genetics Unit. She studies the effects of childhood adversity, which research suggests is responsible for up to one-third of all mental health disorders. Dunn is particularly interested in the timing of these adverse events and in uncovering whether there are sensitive periods during child development when exposure to adversity is particularly harmful. Yet Dunn notes that she and other scientists lack effective tools for measuring exposure to childhood adversity. Asking people (or their parents) about painful experiences in their early years is one method, but that’s vulnerable to poor recall or reluctance to share difficult memories. “That’s a hindrance for this field,” says Dunn.

However, Dunn was intrigued to learn that anthropologists have long studied the teeth of people from past eras to learn about their lives. “Teeth create a permanent record of different kinds of life experiences,” she says. Exposure to sources of physical stress, such as poor nutrition or disease, can affect the formation of dental enamel and result in pronounced growth lines within teeth, called stress lines, which are similar to the rings in a tree that mark its age. Just as the thickness of tree growth rings can vary based on the climate surrounding the tree as it forms, tooth growth lines can also vary based on the environment and experiences a child has in utero and shortly thereafter, the time when teeth are forming. Thicker stress lines are thought to indicate more stressful life conditions.

Dunn developed a hypothesis that the width of one variety in particular, called the neonatal line (NNL), might serve as an indicator of whether an infant’s mother experienced high levels of psychological stress during pregnancy (when teeth are already forming) and in the early period following birth.

To test this hypothesis, Dunn and two co-lead authors—postdoctoral research fellow Rebecca V. Mountain, PhD, and data analyst Yiwen Zhu, MS, who were both in the Psychiatric and Neurodevelopmental Genetics Unit at the time of the study—led a team that analyzed 70 primary teeth collected from 70 children enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC) in the United Kingdom. In ALSPAC (which is also called Children of the 90s), parents donated primary teeth (specifically, the pointed teeth on each side of the front of the mouth known as canines) that naturally fell out of the mouths of children aged 5 to 7. The width of the NNL was measured using microscopes. Mothers completed questionnaires during and shortly after pregnancy that asked about four factors that are known to affect child development: stressful events in the prenatal period, maternal history of psychological problems, neighborhood quality (whether the poverty level was high or it was unsafe, for instance), and level of social support.

Several clear patterns emerged. Children whose mothers had lifetime histories of severe depression or other psychiatric problems, as well as mothers who experienced depression or anxiety at 32 weeks of pregnancy, were more likely than other kids to have thicker NNLs. Meanwhile, children of mothers who received significant social support shortly after pregnancy tended to have thinner NNLs. These trends remained intact after the researchers controlled for other factors that are known to influence NNL width, including iron supplementation during pregnancy, gestational age (the time between conception and birth) and maternal obesity.

No one is certain what causes the NNL to form, says Dunn, but it’s possible that a mother experiencing anxiety or depression may produce more cortisol, the “stress hormone,” which interferes with the cells that create enamel. Systemic inflammation is another candidate, says Dunn, who hopes to study how the NNL forms. And if the findings of this research can be replicated in a larger study, she believes that the NNL and other tooth growth marks could be used in the future to identify children who have been exposed to early life adversity. “Then we can connect those kids to interventions,” says Dunn, “so we can prevent the onset of mental health disorders, and do that as early on in the lifespan as we possibly can.”

Root canal treatment work still favored for badly damaged teeth

 

Few patients regret having a severely damaged tooth saved by a root canal filling. A University of Gothenburg thesis shows that 87 percent would choose the same treatment again, if in need, although pain and discomfort around the tooth are common.

The reason for getting a root filling is often that the soft tissue inside the tooth, the dental pulp, is inflamed or infected. The root canal treatment is carried out in stages, on several occasions. Soft parts are removed and the root canals are finally filled with a combination of a natural, rubberlike material (gutta-percha) and a kind of cement.

Despite generally good oral health, root canal treatment is still a common and necessary measure. In Sweden, as in most countries, most root canal treatments are performed by general dental practitioners in the public or private sector.

For her PhD thesis, dentist Emma Wigsten of the Institute of Odontology at Sahlgrenska Academy, University of Gothenburg, studied various aspects of root canal treatments performed in Swedish general dental practice, with the Public Dental Service in Region Västra Götaland as a base.

Molars difficult to treat

In several of the component studies in Wigsten’s compilation thesis, data on a patient group initially numbering 243 were analyzed. They had all started root canal treatment at one of the 20 public dental clinics in the region. The patients were then followed up for one to three years.

Most of the root canal treatments studied were prompted by toothache in teeth with caries and large restorations, which culminated in root fillings within a year. Molars were an exception: only just over half of the root fillings met their purpose and, as a result, many molars had to be removed (i.e. extracted).

“It seems harder to get a good result in treating the molars, despite time and resources invested. Root canal treatment is complicated: You’re working inside the tooth where you can’t see anything, and the further back you go in the mouth, the more difficult it becomes,” Wigsten says.

“Root canal treatments of molars involve significantly bigger challenges than other tooth groups. So it may be important to investigate whether root canal treatments of molars should be performed to a greater extent by dentists specializing in root canal treatment.”

Satisfaction and quality of life

Half of the patients stated that they had mild pain or discomfort from their root-filled tooth during the follow-up period of up to three years. Nevertheless, the great majority (87 percent) were satisfied. They did not regret their choice to get root canal treatment instead of a tooth extraction.

Another component study, at six public dental clinics in Region Västra Götaland, covered 85 patients in whom either root canal treatment was started or a tooth was removed. An improved health-related quality of life was observed in the patients who started root canal treatment, but not in those who underwent a tooth extraction.

“The studies show that the patients' quality of life benefited from root canal treatment. On the other hand, it’s unclear whether the treatment is cost-effective compared with tooth removal, especially where molars are concerned,” Wigsten concludes.

Title: Root Canal Treatment in a Swedish Public Dental Service: Studies of indications and results, http://hdl.handle.net/2077/68698

Oral health can be an additional, modifiable risk factor for high risk COVID-19 patients

 The correlation between poor oral health and COVID-19 severity, as well as the correlation between oral health and delayed recovery, demonstrates a potential need to consider oral health an additional risk factor for cardiac patients who may contract COVID-19. The new sub-study, examining Egyptian cardiac patients, will be presented at ACC Middle East 2021, a hybrid meeting held in partnership by the American College of Cardiology, Egyptian Society of Cardiology and the ACC Egypt Chapter on Oct. 14-15, 2021.

The oral cavity is a potential reservoir for respiratory pathogens. Previous trials have linked poor oral hygiene with increased inflammation and cardiovascular disease. According to the researchers, COVID-19 severity has also been linked to an inflammatory response.

The researchers hypothesized that increased COVID-19 severity may be linked to poor oral health status, especially in patients with cardiovascular diseases. According to the study authors, the study assessed oral health status, severity of COVID-19 symptoms, C-reactive protein (CRP) levels and duration of recovery.

“Oral tissues could act as a reservoir for SARS-CoV-2, developing a high viral load in the oral cavity. Therefore, we recommended maintenance of oral health and improving oral hygiene measures, especially during COVID-19 infection,” said Ahmed Mustafa Basuoni, MD, cardiology consultant at Cairo University and lead author of the study. “Simple measures like practicing proper oral hygiene, raising awareness of oral health importance either in relation to COVID-19 infection or systemic diseases by using media and community medicine, regular dental visits, especially in patients with CVD, and using [antimicrobial] mouthwashes [could help in] preventing or decreasing the severity of COVID-19 disease.” 

The study included 86 Egyptian heart disease patients with a confirmed COVID-19 PCR test. Using a questionnaire, researchers from Cairo University assessed oral health and COVID-19 severity. An oral health score was used to determine the effect of oral health on COVID-19. Data on CRP levels and COVID-19 PCR tests were collected via the questionnaire and confirmed via medical records. CRP levels are used to determine when there is inflammation in the body.

According to the researchers, the correlation between oral health and COVID-19 severity showed a significant inverse relationship, as did the correlation between oral health with recovery period and CRP values. Poor oral health was correlated to increased values of CRP and delayed recovery, especially in patients with cardiac diseases.

“Oral health should be a part of routine history taking and examination in cardiac patients,” Basuoni said. “Lifestyle measures should be instructed to all cardiac patients regarding good oral hygiene with regular dental visits. We need to give more space in research for these risk factors which can be easily modified.”

Survey of US dentists shows high rate of opioid prescriptions despite knowledge of effective alternatives

 

- A survey of dentists in the United States finds that an overwhelming majority of those who responded believe nonsteroidal anti-inflammatory drug (NSAID)-acetaminophen combinations are as effective or more effective in managing dental pain as opioids; however, almost half say they still prescribe opioids.

The results of the survey, conducted by PharmedOut at Georgetown University Medical Center with  undergraduate students at Georgetown University School of Nursing & Health Studies, were published October 21 in The Journal of the American Dental Association.

“These results suggest that dentists are familiar with the evidence about the effectiveness of NSAID-acetaminophen medications, but their self-reported prescribing patterns demonstrate a disconnect,” says Matthew Heron, the first author who conducted the research as an undergraduate at Georgetown’s School of Nursing & Health Studies.

Previous studies find that dentists comprise 15.8% of opioid prescribers and prescribe 8.6% of opioid medications in the United States. Dentists are the highest prescribers of opioids to patients 18 years and younger.

“We know that the first exposure to opioids for many people occurs in their teens and early 20s following  common dental procedures like third molar extractions,” says Nkechi Nwokorie, who also conducted the work as an undergraduate at Georgetown. “This is a particularly vulnerable population for misuse.”

The Georgetown researchers received 291 survey responses and analyzed 269 completed surveys. Although 84% of respondents reported believing that NSAID-acetaminophen combinations are equally as effective or more effective than opioids, 43% of respondents also reported regularly prescribing opioid medications.

“This underscores the need for more education about the harms of opioids and the need for national guidelines to align clinical practice with current evidence,” concludes Adriane Fugh-Berman, MD, a professor in the departments of pharmacology & physiology, and family medicine at Georgetown University Medical Center. Fugh-Berman is also the director of PharmedOut.

Study: Heartburn drugs may have unexpected benefits on gum disease

 

The use of heartburn medication is associated with decreased severity of gum disease, according to a recent University at Buffalo study.

The research found that patients who used proton pump inhibitors (PPIs) – a class of drugs commonly prescribed to treat heartburn, acid reflux and ulcers – were more likely to have smaller probing depths in the gums (the gap between teeth and gums). When gums are healthy, they fit snuggly against the teeth. However, in the presence of harmful bacteria, the gap deepens, leading to inflammation, bone loss and periodontitis, also known as gum disease.

The findings, published last month in Clinical and Experimental Dental Research, may be linked to the side effects of PPIs, which include changes in bone metabolism and in the gut microbiome, says lead investigator Lisa M. Yerke, DDS, clinical assistant professor in the Department of Periodontics and Endodontics at the UB School of Dental Medicine.

“PPIs could potentially be used in combination with other periodontal treatments; however, additional studies are first needed to understand the underlying mechanisms behind the role PPIs play in reducing the severity of periodontitis,” says Yerke.

Additional investigators include first author and UB alumnus Bhavneet Chawla, and Robert E. Cohen, DDS, PhD, professor of periodontics and endodontics in the UB School of Dental Medicine.

The study sought to determine whether a relationship exists between PPI use and gum disease. The researchers analyzed clinical data from more than 1,000 periodontitis patients either using or not using PPIs. Probing depths were used as an indicator of periodontitis severity.

Only 14% of teeth from patients who used PPIs had probing depths of 6 millimeters or more, compared to 24% of teeth from patients who did not use the medication. And 27% of teeth from patients using PPIs had probing depths of 5 millimeters or more, compared to 40% of teeth from non-PPI users, according to the study.

The researchers theorized that PPIs’ ability to alter bone metabolism or the gut microbiome, as well as potentially impact periodontal microorganisms, may help lessen the severity of gum disease.

Additional studies are under development to determine if this relationship can be found in other populations of patients with gum disease, and to learn to what extent the relationship can be directly attributed to PPIs, says Yerke.

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JOURNAL

Clinical and Experimental Dental Research

DOI

https://doi.org/10.1002/cre2.495 

ARTICLE TITLE

Association between proton pump inhibitors and periodontal disease severity

Multiple bacteria types found to contribute to bone loss in gum disease

 

IMAGE: THE DATA EXPRESSED AS THE MEAN ± SEM OF 6 MICE. A SIGNIFICANT DIFFERENCE BETWEEN THE TWO GROUPS WAS INDICATED; *P<0.05 AND **P<0.01 VS PBS, BY STUDENT’S T-TEST. SCALE BAR INDICATED 1 MM. view more 

CREDIT: MASAKI INADA / TUAT

Mouths are filthy, harboring the second largest microbiome of the human body. Some bacteria can help break down food, among other responsibilities; other bacteria can travel into the mouth on food, fingers, pen caps and more to contribute to gum disease and other oral infections. More than good or bad bacteria, researchers have now unveiled that positive and negative bacterium are responsible for periodontitis symptoms — Gram-positive and Gram-negative, that is.

Gram-positive bacteria have thicker cell walls that retain the purple color from Gram stain, which can quickly differentiate cell types based on the width of their cell walls. For the first time, researchers found that Gram-positive bacteria can also induce the resorption of the bone that holds teeth in place, called the alveolar bone. The results were published on June 25 in Scientific Reports.

“This finding is a new concept: both Gram-positive and -negative bacteria are involved in the progression of periodontal bone loss,” said lead author Masaki Inada, associate professor in the Department of Biotechnology and Life Science at the Tokyo University of Agriculture and Technology (TUAT). “In a healthy condition, the tooth root is embedded into a socket in the alveolar bone in periodontal tissue. Infection of mixed multiple Gram-negative bacteria resulted in alveolar bone resorption and tooth loss induced by severe inflammation in periodontal tissues. It is well-known that the major pathogens of periodontitis are dominantly gram-negative bacteria. It was unclear whether gram-positive bacteria are associated with or contribute to the progression of periodontal bone loss.”

In a previous study, the researchers injected lipopolysaccharide (LPS) from Gram-negative bacteria into mice engineered without the gene that produces molecules that gather at sites of damaged tissue. Without these molecules, called prostaglandin E2 (PGE2), the LPS failed to induce bone loss. This suggested, Inada said, that PGE2 is required for periodontitis to progress.

“LPS is considered to be a dominant pathogen causing inflammatory bone resorption in periodontitis,” Inada said. “On the other hand, Gram-positive bacteria have been known to contribute to the inflammation of the periodontal gums in the initial phases of periodontitis; however, there was little evidence to show that these pathogens contribute to the induction of inflammatory bone resorption in the late phase of periodontitis.”

It comes down to bone remodeling, according to Inada. At what point does cell death from the infection outpace the body’s effort to create new bone cells?

“Several reasons could be counting and explaining on these phenomena, “ Inada said.

In the case of LPS in the PGE2-deficient mice, the balance stayed in favor of bone formation. But when the researchers introduced lipoteichoic acid (LTA), a major component of the cell wall in Gram-positive bacteria, the balance tipped to bone resorption. The researchers injected mice with periodontitis with LTA and found that it increased the amount of PGE2, resulting in bone resorption. They also saw that Gram-positive bacteria proliferated at a higher rate than Gram-negative bacteria and they preferred to occupy the depths of the teeth pockets — suggesting a more potent dose of LTA closer to the site of bone lose, according to Inada.

“Our goal is to clarify the crosstalk of Gram-positive and -negative bacteria for the pathogenesis and progression of periodontal bone loss,” Inada said. “The understanding of the mechanisms will contribute to developing novel drugs for the treatment of periodontal bone loss.”