New material to replace extracted human teeth for dental research

 

 

IMAGE: FIBRE-REINFORCED COMPOSITE ELLIPTICAL FRUSTUMS - DENTINE ANALOGUE MATERIAL (SUBSTRATE) IN CERAMIC CROWN FATIGUE TEST. view more 

CREDIT: THE UNIVERSITY OF HONG KONG

Extracted human teeth have long been used in conducting dental research, such as evaluating dental ceramic materials as a crown restoration on tooth. It is an inexpensive and straightforward process that simulates clinical situations. However, the collection and use of extracted human teeth is becoming increasingly difficult given the concerns about COVID-19, size-standardisation issues, and also time constraints. All these factors have prompted a need for dentine analogue materials that could potentially substitute extracted human teeth in laboratory-based mechanical and fatigue tests.

A research team led by Dr James Tsoi, Associate Professor in Dental Materials Science from the Faculty of Dentistry at the University of Hong Kong (HKU), together with colleagues from Wuhan University, China, and Drexel University, USA, investigated new elliptical frustums of fibre-reinforced composite materials and compared their properties to that of human dentine.

The materials were tested for their mechanical strength, elastic modulus, indentation hardness and fatigue behaviour. Fatigue behaviour indicates the tenacity of materials under varying loads. The positive results showed that the dentine analogue materials analysed can be used as a replacement for human-extracted teeth.

The study entitled “Which dentine analogue material can replace human dentine for crown fatigue test?”, has been published online in Dental Materials. Based on this study, a dental company contracted the Faculty of Dentistry to test commercial ceramic products using the same methodology.

The researchers uniformly fabricated the new dentine analogue materials with specific size and shape mimicking natural teeth, adhesively bonded to lithium disilicate crowns, and subjected to fatigue loading — the restorations showed comparable fatigue failure load and lifetime (durability) to those based on extracted human teeth. This implies that the materials can be well used in lieu of human-extracted teeth.

Finite element analysis, an important method to simulate a physical phenomenon using a numerical technique, also showed promising results. Similar stress levels and distributions between dentine analogue materials and extracted human teeth were observed. Notably, it is pivotal that the new materials have similar elastic properties and fatigue performance to human dentine if researchers want to use them for laboratory fatigue tests.

“This study evaluated the mechanical properties and fatigue behaviour of dentine analogue materials experimentally, analytically and numerically, and found a material with spectacular size and shape can reliably replace human dentine as the substrate in a ceramic crown fatigue test,” said principal investigator Dr James Tsoi.

“We hope this study can help researchers who are facing the problem of inadequate extracted human teeth and facilitate predictable laboratory research with the aid of dentine analogue materials,” he added.

The study was supported by the General Research Fund (GRF). Its preliminary results were presented by Ms Yanning Chen, a co-investigator, at the Academy of Dental Materials Annual Meeting 2022 and awarded with the Student Travel Award.

Please click here for the article entitled “Which dentine analogue material can replace human dentine for crown fatigue test.

Gum inflammation parallels novel “cytokine score”

Researchers at NYU College of Dentistry have developed a single score to describe the level of cytokines in the saliva, and this score is linked with the severity of clinical gum inflammation, according to a study published in the journal PLOS ONE. 

 

While more research is needed to test the “cytokine score,” it could hold promise for measuring how well a patient responds to treatment for gum disease, predicting gum disease recurrence, or detecting ongoing inflammation related to systemic diseases. 

 

“Periodontal inflammation is not just apparent upon examination, but is reflected in the patient’s saliva,” said Angela Kamer, DMD, MS, PhD, associate professor of the Ashman Department of Periodontology & Implant Dentistry at NYU Dentistry and the study’s senior author.

 

Periodontal (or gum) disease is a chronic, inflammatory condition that affects roughly half of adults. Marked by inflamed gums, which can bleed and detach from the tooth, periodontal disease results from the complex interaction between an imbalance of healthy and unhealthy bacteria under the gumline and the immune system’s response. This response produces high levels of cytokines—small proteins that signal the immune system—in the inflamed gums, especially pro-inflammatory cytokines such as IL-8, IL-1β, IL-6 and TNFα.

 

Periodontal disease is also associated with systemic conditions including cardiovascular disease, diabetes, and Alzheimer’s. Scientists believe that gum inflammation contributes to these conditions through both indirect pathways (cytokines boosting systemic inflammation) and direct pathways (cytokines traveling to a specific organ like the heart or brain), but studying this is difficult due to the challenge of measuring cytokines in the fluid found deep in the pockets in the gums.

 

Fortunately, cytokines are also found in the saliva, which is easier to collect. In the PLOS ONE study, the researchers wanted to know if clinically detected gum inflammation could predict the level of cytokines found in saliva. 

 

“Salivary cytokines are a window into the molecular make-up of the oral environment,” said Vera Tang, DDS, MS, clinical assistant professor of the Ashman Department of Periodontology & Implant Dentistry at NYU Dentistry and the study’s first author.

 

The researchers evaluated the gums and saliva of 67 adults, ages 45 and older, who had some degree of periodontal disease but were otherwise healthy. To measure their clinical periodontal inflammation, the researchers used a formula called the Periodontal Inflamed Surface Area (PISA), which is calculated using measurements of the depth of pockets in the gums and bleeding upon probing. PISA provides a single measure of periodontal inflammation; a higher PISA score indicates worse inflammation.

 

Participants were also asked to spit into sterile tubes to capture saliva samples, which were then analyzed to measure a range of both pro- and anti-inflammatory cytokines: IL-1β, IL-6, IL-8, IL-13, TNF-α, and IL-10. Led by statistician Malvin Janal, PhD, the researchers used two different ways (the Cytokine Component Index and Composite Inflammatory Index) to combine these cytokines into a single score.

 

They found that PISA scores were significantly associated with the new cytokine scores, independent of other factors including age, gender, smoking, and body mass index (BMI). The higher a cytokine score, the greater the periodontal inflammation.

 

“This demonstrates that a single score encompassing several salivary cytokines correlates with the severity of periodontal inflammation,” said Leena Palomo, DDS, MSD, professor and chair of the Ashman Department of Periodontology & Implant Dentistry at NYU Dentistry, and a study coauthor. 

 

The researchers caution that more research is needed to validate the cytokine score in patients with different health conditions, as well as those with all levels of periodontal disease, including healthy gums and early-stage gum disease. However, if the cytokine score is validated in larger and more diverse patient populations, it could be used to better understand periodontal disease progression and recurrence, as well as the potential connection to other systemic conditions.  

 

“With treatment for gum disease, such as scaling and planing, we know that the PISA score goes down. It would be interesting to see if the cytokine score also drops—or, if it persists, look into what that means,” added Kamer. “Is it picking up an underlying cause, like ongoing inflammation from systemic disease? Or if someone has a hyperinflammatory response, which we’d know from a high cytokine score, can it predict if periodontitis will recur or progress in the future? We hope to look into these questions in future research.”

Dental service use falls, oral health worsens after people become eligible for Medicare

 

For nearly 1 in 20 adults, Medicare eligibility was associated with the loss of all their teeth

Peer-Reviewed Publication

BRIGHAM AND WOMEN'S HOSPITAL

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Half of all older adults in the U.S. lack dental insurance and, in 2018, nearly half of older adults received no dental care. A new study by investigators from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, examined changes in dental care and oral health after older adults become eligible for Medicare, the traditional version of which covers medical services, but not dental care. Among more than 97,000 people, the researchers found a dramatic drop in the percentage of people receiving restorative dental care and an almost 5 percentage point increase the number people who lost all their teeth after they turned 65 and became eligible for Medicare. Their results are published in Health Affairs.

“Older adults have the lowest rates of dental insurance in the U.S. and cost is a major barrier for many in seeking dental care,” said corresponding author Lisa Simon, MD, DMD, a resident in the Brigham’s Department of Medicine. “We know that Medicare, by covering medical services, improves health outcomes and reduces racial health inequities among older adults, but it has the exact opposite effect for dental care.”

With very limited exceptions, traditional Medicare does not cover dental services. Medicare Advantage plans can offer dental services, but the extent of coverage varies. Federal efforts to expand Medicare dental coverage have not passed and policy debates about dental benefits are ongoing.

Simon and colleagues analyzed national data from the Medical Expenditure Panel Surveys from 2010 to 2019, examining changes in dental insurance and oral health care immediately after respondents became eligible for Medicare. The surveys included community-dwelling adults ages 50 to 85.

The team found that both traditional Medicare and Medical Advantage beneficiaries experienced immediate and long-term reductions in dental services use after Medicare enrollment. While the total number of annual dental visits did not change, the number of visits for restorative procedures, such as fillings or crowns, decreased by 8.7 percent. Adults also experienced an increase in complete edentulism—loss of all teeth—which puts people at higher risk of poor nutrition, lower quality of life and progression of cognitive impairment.

“Loss of teeth can have a number of negative downstream effects,” said Simon. “It’s associated with many geriatric conditions, including frailty and cognitive function.”

The authors note that the survey data used did not allow them to follow participants over long periods and the changes detected could be confounded by other life changes at age 65, such as retirement or receipt of Social Security income. Using other forms of survey data could help investigators focus on at-risk populations, such as adults living in long-term care facilities, and could help to identify and compare what dental benefit Medicare Advantage programs offer.

“Without dental coverage for adults who are eligible Medicare, we are seeing a rise in loss of teeth after age 65 among nearly 1 in 20 adults, which represents millions of Americans,” said Simon. “Our findings capture the magnitude of the problem but also point to the opportunity to improve oral health care access and outcomes, should policy makers expand Medicare coverage to include dental services.”

Disclosures: Simon received funding for consulting work with the CareQuest Foundation and the PrimaryCare Collaborative in 2020 and 2021.

Funding: This research was supported by the National Institute on Aging, National Institutes of Health (NIH) (Grant No. K23 AG058806), the Office of the Director, NIH (NIH Director’s Early Independence Award, DP5-OD024564).

Paper cited: Simon L et al. “Dental Services Use: Medicare Beneficiaries Experience Immediate And Long-Term Reductions After Enrollment” Health Affairs DOI: 10.1377/hlthaff.2021.01899

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Health Affairs

DOI

10.1377/hlthaff.2021.01899 

Obstructive sleep apnea tied to weaker bones and teeth in adults

 Obstructive sleep apnea may be linked to low bone mineral density in adults, according to University at Buffalo-led research. 

The findings are crucial for individuals with sleep apnea, as low bone mineral density is an indicator of osteoporosis – a condition in which bones become weak and brittle. In addition to increasing the risk of fractures, low bone mineral density also impacts oral health, causing teeth to become loose and dental implants to fail, says senior author Thikriat Al-Jewair, DDS, associate professor of orthodontics in the UB School of Dental Medicine and director of the school’s Advanced Education Program in Orthodontics.

The study was published in November in The Journal of Craniomandibular and Sleep Practice. The researchers used cone beam computed tomography (CBCT) – a type of X-ray – to measure bone density in the head and neck of 38 adult participants, half of whom had obstructive sleep apnea.

When controlling for age, sex and weight, the participants with obstructive sleep apnea had significantly lower bone mineral density than the participants without the condition. 

Obstructive sleep apnea, which is characterized by difficulty breathing while asleep, can cause hypoxia (low levels of oxygen in the body), inflammation, oxidative stress and shortened breathing patterns. Each of these symptoms may have a chronic negative effect on bone metabolism and, ultimately, bone density, says Al-Jewair.

“While the link between obstructive sleep apnea and low bone mineral density has yet to be fully explored, this study offers new evidence on their connection that could have several implications for orthodontic treatment,” says Al-Jewair, also assistant dean for equity, diversity and inclusion in the UB School of Dental Medicine. 

“If a patient has been diagnosed with sleep apnea, this can influence treatment planning and management. CBCT imaging has become an integral part of daily orthodontic practice and could be used as a screening tool for low bone mineral density,” she said. “Orthodontists could then inform their patients of their propensity for low bone mineral density and encourage them to seek further consultation with their physician, as well as warn the patient of possible adverse outcomes, increased risks and effects on treatment time.”

Future research with larger sample sizes is needed, says Al-Jewair.

Additional investigators include first author Mira Daljeet, DMD, former resident in the UB Department of Orthodontics; David Covell, DDS, PhD, professor and L.B. Badgero Endowed Chair of the UB Department of Orthodontics; Stephen Warunek, DDS, UB clinical assistant professor of orthodontics; Alberto Monegro, MD, attending physician in the Jacobs School of Medicine and Biomedical Sciences at UB; and Terry Giangreco, DDS.

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DOI

10.1080/08869634.2022.2142724 

Study compares pharmacologic treatments for managing tooth extraction pain

 A recent study published in the Journal of Dental Research (JDR) has compared the effectiveness of ten pharmacological interventions in order to develop guidelines for acute pain management after tooth extraction in adults.

North America is amid an opioid crisis, which is a leading public health and safety concern. In dentistry, many patients are prescribed opioids for the first time to manage acute postoperative pain after dental impaction surgery, which often results in prescription of an excess number of opioid pills, thereby increasing the risk of misuse, abuse, and addiction. Of over half a million dental patient visits between 2011 and 2015, 29% of prescribed opioids exceeded the recommended morphine equivalent for appropriate management of acute pain and over half exceeded the recommended days of supply.

The current clinical practice guidelines lack evidence-based guidance on effective management of acute dental pain. The National Academies’ report entitled “Framing Opioid Prescribing Guidelines for Acute Pain”, highlighted the need to formalize evidence-based alternatives to opioid analgesics in a clinical practice guideline.

The study by Anna Miroshnychenko from McMaster University Faculty of Health Sciences and colleagues involved systematic review (SR) and network meta-analysis (NMA) to assess the comparative effectiveness of ten different pharmacological interventions for the management of pain subsequent to simple and surgical tooth extraction, and pain associated with pulpitis or its complications. This SR was conducted to inform the 2022 evidence-based clinical practice guidelines produced by the American Dental Association (ADA) Council on Scientific Affairs, the ADA Science & Research Institute (ADASRI) and the University of Pittsburgh’s and the University of Pennsylvania’s Schools of Dental Medicine in partnership with the United States Food and Drug Administration (FDA) for the management of acute dental pain.

The study concluded that, based on moderate and high certainty evidence, in individuals undergoing surgical tooth extractions, the interventions classified as the most effective for pain relief were ibuprofen 200-400 mg plus acetaminophen 500-1,000 mg, acetaminophen 650 mg plus oxycodone 10 mg, ibuprofen 400 mg, and naproxen 400-440 mg. Further, NSAIDs with or without acetaminophen result in better pain-related outcomes than opioids with or without acetaminophen (except acetaminophen 650 mg plus oxycodone 10 mg) or placebo. Future research should focus on the assessment of ibuprofen 200 mg plus hydrocodone 5 mg, hydrocodone 5 mg plus acetaminophen 300-325 mg and tramadol 37.5 mg plus acetaminophen 325 mg through randomized clinical trials.

About the Journal of Dental Research

The Journal of Dental Research (JDR) is a multidisciplinary journal dedicated to the dissemination of new knowledge in all sciences relevant to dentistry and the oral cavity and associated structures in health and disease. The JDR Editor-in-Chief is Nicholas Jakubovics, Newcastle University, England. To learn more, visit https://journals.sagepub.com/home/jdr and follow JDR on Twitter at @JDentRes!

About IADR

The International Association for Dental Research (IADR) is a nonprofit organization with over 10,000 individual members worldwide, with a Mission to drive dental, oral and craniofacial research to advance health and well-being worldwide. To learn more, visit www.iadr.org.

About AADOCR
The American Association for Dental, Oral, and Craniofacial Research (AADOCR) is a nonprofit organization with over 3,000 members in the United States with a mission to drive dental, oral, and craniofacial research to advance health and well-being. AADOCR is the largest division of the International Association for Dental Research which has over 10,000 members. Learn more at www.aadocr.org.

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JOURNAL

Journal of Dental Research