New 'tooth-on-a-chip' could lead to more personalized dentistry M

A so-called "tooth-on-a-chip" could one day enable more personalized dentistry, giving dentists the ability to identify dental filling materials that work better and last longer based on a patient's own teeth and oral microbiome.
The miniaturized tooth system is a thin slice of a human molar placed in between transparent rubber slides that are etched with tiny channels, through which fluids flow. The research device mimics a real tooth with a cavity, which allows fluids and bacteria to move between the cavity opening and the inner tooth. Scientists use a microscope to observe the tooth as it interacts with materials and bacteria.
While other mini organs such as livers and lungs have been placed on chips like this for research purposes, this is the first time an organ-on-a-chip system has been created for dental research, reports a paper published in the Royal Society of Chemistry journal Lab on a Chip.
"Today's cavity fillings don't work as well as they should. They last for five, seven years on average, and then they break off," said the paper's corresponding author, Luiz E. Bertassoni, D.D.S., Ph.D., associate professor of restorative dentistry in the OHSU School of Dentistry and biomedical engineering in the OHSU School of Medicine.
"They don't work because we haven't been able to figure out what's happening at the interface of the tooth and the filling," Bertassoni continued. "This device can help address that by giving us a close-up view of what's happening there in real time. Years from now, dentists could extract a tooth from a patient, load it into this device, observe how a dental filling material interacts with the tooth, and pick a material that's best for that particular patient."
The device is designed to help scientists better understand the innerworkings of dental cells in their natural environment. For example, researchers could use the tooth-on-a-chip to better understand how teeth form and how they respond biologically to all sorts of injuries and treatments.
"It opens up a new window into the complexity of dental care that could change the way we do dentistry quite significantly," Bertassoni said.

Saliva test shows promise for earlier and easier detection of mouth and throat cancer

A novel noninvasive technique may detect human papilloma virus-16, the strain associated with oropharyngeal cancer, in saliva samples, reports The Journal of Molecular Diagnostics

Elsevier

IMAGE: Acoustofluidic exosome isolation chip for salivary exosome isolation. The microfluidic channel is shown by red dye solution and the coin demonstrates the size of the chip. Two pairs of gold... view more 

Credit: The Journal of Molecular Diagnostics

Philadelphia, December 13, 2019 - Unfortunately, cancers that occur in the back of the mouth and upper throat are often not diagnosed until they become advanced, partly because their location makes them difficult to see during routine clinical exams. A report in the Journal of Molecular Diagnostics, published by Elsevier, describes the use of acoustofluidics, a new non-invasive method that analyzes saliva for the presence of human papilloma virus (HPV)-16, the pathogenic strain associated with oropharyngeal cancers (OPCs). This novel technique detected OPC in whole saliva in 40 percent of patients tested and 80 percent of confirmed OPC patients.
"OPC has an approximate incidence of 115,000 cases per year worldwide and is one of the fastest-rising cancers in Western countries due to increasing HPV-related incidence, especially in younger patients. It is paramount that surveillance methods are developed to improve early detection and outcomes," explained co-lead investigator Tony Jun Huang, PhD, Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, USA.
"Considering these factors, the successful detection of HPV from salivary exosomes isolated by our acoustofluidic platform offers distinct advantages, including early detection, risk assessment, and screening," added Dr. Huang. This technique may also help physicians predict which patients will respond well to radiation therapy or achieve longer progression-free survival.
Exosomes are tiny microvesicles originating within cells that are secreted into body fluids. They are believed to play a role in intercellular communication and their numbers are elevated in association with several types of cancers. Acoustofluidics is an advanced technology that fuses acoustics and microfluidics. Fluid samples are analyzed using a tiny acoustofluidic chip developed to isolate salivary exosomes by removing unwanted particles based on size, leaving exosome-rich concentrated samples that make it easier to detect tumor-specific biomarkers.
In this study investigators analyzed saliva samples from 10 patients diagnosed with HPV-OPC using traditional methods. They found that the technique identified the tumor biomarker HPV-16 DNA in 80 percent of the cases when coupled with droplet digit PCR. Since this method is independent of sample variability that arises due to changes in saliva viscosity and collection methods used, it may prove ideal for use in clinical settings.
Dr. Huang highlighted some of the technique's features, including automated and fast exosome isolation (less than five minutes of processing time compared to approximately eight hours of processing time using benchmark technologies). Analyses can be performed at relatively low cost and at points of care. Also, it is suitable for repeated and continuous monitoring of tumor progression and treatment, unlike traditional biopsy.
"With these features, the acoustofluidic technology has the potential to significantly exceed current industry standards, address unmet needs in the field, help expedite exosome-related biomedical research, and aid in the discovery of new exosomal biomarkers," commented Dr. Huang.
"The saliva exosome liquid biopsy is an effective early detection and risk assessment approach for OPC," said co-lead investigator David T.W. Wong, DMD, DMSc, of the Center for Oral/Head and Neck Oncology Research, School of Dentistry at the University of California Los Angeles, CA, USA. "The acoustofluidic separation technique provides a fast, biocompatible, high-yield, high-purity, label-free method for exosome isolation from saliva." According to the researchers, this technology can also be used to analyze other biofluids such as blood, urine, and plasma.

No evidence to suggest that conventional fillings are more successful than sealing decay into teeth, or using preventive methods alone.

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A dentist's drill might not be the best way to tackle tooth decay in children's teeth, a new study has concluded.

Findings from a major dental trial suggest that preventing tooth decay from occurring in the first place is the most effective way for parents to help avoid pain and infection from decay in their children's teeth.
A three-year study comparing three different treatment options for tooth decay in children's teeth, led by dentists from the Universities of Dundee, Newcastle, Sheffield, Cardiff, Queen Mary University of London and Leeds, has found no evidence to suggest that conventional fillings are more effective than sealing decay into teeth, or using prevention techniques alone, in stopping pain and infection from tooth decay in primary teeth.
The FiCTION trial, the largest of its kind to date, also found that 450 children who took part in the study experienced tooth decay and pain, regardless of which kind of dental treatment they received.
Professor Nicola Innes, Chair of Paediatric Dentistry at the University of Dundee and lead author on the paper published today, said, "Our study shows that each way of treating decay worked to a similar level but that children who get tooth decay at a young age have a high chance of experiencing toothache and abscesses regardless of the way the dentist manages the decay.
"What is absolutely clear from our trial is that the best way to manage tooth decay is not by drilling it out or sealing it in -- it's by preventing it in the first place."
During the study, more than 1,140 children between the ages of three and seven with visible tooth decay were recruited by dentists working in one of 72 dental clinics throughout the country. One of three treatment approaches was then chosen randomly for each child's dental care for the duration of the trial, which was up to three years.
The first approach avoided placing any fillings and aimed to prevent new decay by reducing sugar intake, ensuring twice-daily brushing with fluoridated toothpaste, application of fluoride varnish and placing of fissure sealants on the first permanent molar (back) teeth.
The second option involved drilling out tooth decay, which was based upon what has been considered the standard "drill and fill" practice for more than 50 years together with preventive treatments. The third treatment strategy was a minimally invasive approach where tooth decay was sealed in under a metal crown or a filling to stop it progressing together with preventive treatments.
The main trial findings, published in the Journal of Dental Research found no evidence to suggest that any of the treatment strategies were better than another in terms of making a difference in children's experience of pain or infection, quality of life or dental anxiety between groups.
All three different ways of treating decay were acceptable to children, parents and dental professionals.
Sealing-in with preventive treatment was most likely to be considered the best way of managing children's decay if society are willing to pay a minimum of £130 to avoid an episode of pain or infection.
Professor Anne Maguire, Chair of Preventive Dentistry at Newcastle University and one of the co-chief investigators said, "The FiCTION findings have focused attention again on the need to prevent dental decay before it begins but also provided some reassurance that if decay does develop in a child's mouth, there are a number of treatment options available which can be tailored to the clinical and behavioural needs of an individual child."
Professor Gail Douglas, Chair of Dental Public Health at the University of Leeds and one of the chief investigators, said, "All of the children in our study were chosen to take part because they already had tooth decay and unfortunately even with lots of care and attention from the dentist once children have decay, there's quite a chance that it will cause further problems.
"The good news however is that tooth decay can be prevented. Brushing your teeth with fluoride toothpaste, especially last thing before bedtime, avoiding sugary drinks and snacks between meals and seeing a dentist regularly are all small habits that can help boost the overall health of your teeth."
Scotland's Chief Dental Officer, Tom Ferris, said, "FiCTION highlights the importance of preventing tooth decay in our youngest children. I believe the key to success in prevention lies within families and communities; for this reason Scottish Government launched the Oral Health Community Challenge Fund for Third Sector organisations working alongside families living in our most disadvantaged areas. The activities from these projects complement our mainstream Childsmile work in education and health settings."
The FICTION study was funded by the Health Technology Assessment (HTA) programme of the National Instit11/26/2019ute for Health Research (NIHR).

New study explores the link between obesity and gum disease

Obesity and gum (periodontal) disease are among the most common non-communicable diseases in the United States--and studies show these chronic conditions may be related. This new study explores the effect of obesity on non-surgical periodontal care and evaluates potential pathways that may illustrate the connection between the two conditions.
The connection between obesity and gum disease isn't as simple as cause-and-effect, said Andres Pinto, professor of oral and maxillofacial medicine and diagnostic sciences at the Case Western Reserve University School of Dental Medicine and co-author of the study published in the British Dental Journal.
Instead, the relationship centers on what both diseases have in common: inflammation.
Examining a plethora of existing studies, researchers found that data showing increased body mass index, waist circumference and percentage of body fat to be associated with an increased risk to develop gum disease, also known as periodontitis. Most studies analyzed data from population subsets at one point in time, as opposed to studying the same population over a longer period.
They concluded that changes in body chemistry affect metabolism, which, in turn causes inflammation--something present in both maladies.
"Periodontal disease occurs in patients more susceptible to inflammation--who are also more susceptible to obesity," Pinto said.
This information can inform how health-care professionals plan treatments for patients suffering from obesity and/or gum disease, Pinto said.
"Oral health-care professionals need to be aware of the complexity of obesity to counsel their patients about the importance of an appropriate body weight and maintaining good oral hygiene," he said.
Pinto said further research on the relationship between gum disease and obesity is needed, noting there is, at this point, limited evidence to recommend changes in treatment planning.
"There is a thought, from the clinical perspective, that if you treat one of the issues, it may impact the other," he said. "This is the big question. For example, if we treat obesity successfully, will this impact periodontal disease to the point of being of clinical relevance compared to control population. The jury is still out given the paucity of controlled, well designed, clinical trials on this issue."

Brush your teeth to protect the heart

Brushing teeth frequently is linked with lower risks of atrial fibrillation and heart failure, according to a study published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).1
Previous research suggests that poor oral hygiene leads to bacteria in the blood, causing inflammation in the body. Inflammation increases the risks of atrial fibrillation (irregular heartbeat) and heart failure (the heart's ability to pump blood or relax and fill with blood is impaired). This study examined the connection between oral hygiene and occurrence of these two conditions.
The retrospective cohort study enrolled 161,286 participants of the Korean National Health Insurance System aged 40 to 79 with no history of atrial fibrillation or heart failure. Participants underwent a routine medical examination between 2003 and 2004. Information was collected on height, weight, laboratory tests, illnesses, lifestyle, oral health, and oral hygiene behaviours.
During a median follow-up of 10.5 years, 4,911 (3.0%) participants developed atrial fibrillation and 7,971 (4.9%) developed heart failure.
Tooth brushing three or more times a day was associated with a 10% lower risk of atrial fibrillation and a 12% lower risk of heart failure during 10.5-year follow up. The findings were independent of a number of factors including age, sex, socioeconomic status, regular exercise, alcohol consumption, body mass index, and comorbidities such as hypertension.
While the study did not investigate mechanisms, one possibility is that frequent tooth brushing reduces bacteria in the subgingival biofilm (bacteria living in the pocket between the teeth and gums), thereby preventing translocation to the bloodstream.
Senior author Dr. Tae-Jin Song of Ewha Womans University, Seoul, Korea noted that the analysis was limited to one country and as an observational study does not prove causation. But he added: "We studied a large group over a long period, which adds strength to our findings."
An accompanying editorial states: "It is certainly too early to recommend tooth brushing for the prevention of atrial fibrillation and congestive heart failure". It adds: "While the role of inflammation in the occurrence of cardiovascular disease is becoming more and more evident, intervention studies are needed to define strategies of public health importance."2

References
1Chang Y, Woo HG, Park J, et al. Improved oral hygiene care is associated with decreased risk of occurrence for atrial fibrillation and heart failure: A nationwide population-based cohort study. Eur J Prev Cardiol. 2019. doi:10.1177/2047487319886018.
2Meyre P, Conen D. Does tooth brushing protect from atrial fibrillation and heart failure? Eur J Prev Cardiol. 2019. doi:10.1177/2047487319886413.