Thursday, December 24, 2015

Inorganic mercury is from dental fillings is very damaging to key cell processes


University of Georgia research has found that inorganic mercury, which was previously thought to be a less harmful form of the toxic metal, is very damaging to key cell processes.

This study is the first to compare the effects of inorganic and organic mercury compounds at the biochemical, physiological and proteomic levels in any model organism, according to the study's lead author Stephen LaVoie, a microbiology doctoral student. Published in December in the Journal of Biological Inorganic Chemistry, the research looked at how inorganic and organic mercury affected specific molecular processes.

Inorganic mercury from the ore cinnabar was used for centuries against infections; in modern times, humans synthesized organic mercurials as antimicrobials, such as merthiolate.

"Today, most human exposure to inorganic mercury is from dental fillings, and organic mercury exposure is from methylmercury in fish," said study co-author Anne Summers, a microbiology professor in the Franklin College of Arts and Sciences.

Organic mercury exposure is associated with neurological disease, LaVoie explained, whereas inorganic mercury is known to cause neurological, kidney and autoimmune diseases. However, the molecular basis for their distinct toxicity profiles was not understood.

Owing to concern about fish consumption, most research has emphasized organic mercury, assuming it was more toxic, LaVoie said. But comparing them on key cellular processes, he found that inorganic mercury "caused more damage at lower concentrations than organic mercury."

For his study, LaVoie used a common lab strain of E. coli bacteria as a model cellular system. He exposed growing cells to mercury compounds and measured their reactive sulfur called thiols -- essential metals and proteins that naturally bind essential metals via amino acid thiols.

"We used a fluorescent probe to detect thiols," LaVoie said. After mercury exposure the thiols decreased more with inorganic than organic mercury. Inorganic mercury was much more efficient at removing iron from iron-dependent proteins than the best organic mercury compound tested.

"As fellow oxygen-breathing creatures, it's important to know that inorganic mercury is more potent than organic mercury in disrupting protein-iron centers such as those we have in our own cells, " Summers said.

"More is being learned about the bacteria in and on our bodies," LaVoie said. "What we ingest affects them, too, and their health affects our health."

Future work will examine the mercury resistance genes that many bacteria have and how these genes help spread antibiotic resistance genes.

Wednesday, December 23, 2015

Dental implant complications and peri-implantitis


The International and American Associations for Dental Research (IADR/AADR) have published in the January issue of the Journal of Dental Research articles that explore new evidence on the biological complications of dental implants and the great challenges associated with predictable implant therapy.

Dental implants have become an important treatment for the replacement of teeth lost due to disease, injury or congenital tooth agenesis. Over the past 30 years, the incorporation of dental implants into everyday clinical dental practice has resulted in major improvements in oral health of patients through enhancements in function, esthetics and phonetics.

"While dental implant therapy remains an important treatment modality to replace missing teeth, these studies also underscore the importance of tooth preservation in patients susceptible to gum infections such as periodontitis. The caution is that careful assessments and treatment planning amongst dental generalists and specialists should be performed to optimize the clinical decision-making for patients receiving advanced reconstructive implant or periodontal therapy," said JDR Editor William Giannobile. "We believe the outcomes of these studies will be beneficial to patient care and oral health."

The erroneous belief of implants yielding a better long-term prognosis than teeth has now clearly been rejected in several comparative studies and systematic reviews. Teeth even compromised because of periodontal disease or endodontic problems may have a longevity that surpasses that of the average implant in many cases.

Some of the articles in the January issue that elaborate on the prevalence of peri-implantitis and risk of dental implant loss include an editorial from Dennis Tarnow on 'Increasing Prevalence of Peri-implantitis-How Will We Manage?'; and another editorial 'Are Dental Implants a Panacea or Should We Better Strive to Save Teeth?', authored by William Giannobile and Klaus Lang; 'Surgical Treatment of Peri-implantitis. A Randomized Controlled Clinical Trial' by Olivier Carcuac et al; 'Prevalence of Peri-implantitis' by Jan Derks et al among other papers in this issue.

This issue also includes a freely accessible podcast to the JDR article titled 'Prevalence of Peri-implantitis' of an interview with leading experts in implant therapy by Tord Berglundh of the Sahlgrenska Academy, Department of Periodontology at Gothenburg University, Sweden and Dennis Tarnow of Columbia University in New York, USA. Please visit the JDR website at jdr.sagepub.com/site//misc/Index/Podcasts.xhtml to access the podcast.

Tuesday, December 22, 2015

Tooth fillings of the future may incorporate bioactive glass


A few years from now millions of people around the world might be walking around with an unusual kind of glass in their mouth, and using it every time they eat.

Engineers at Oregon State University have made some promising findings about the ability of "bioactive" glass to help reduce the ability of bacteria to attack composite tooth fillings - and perhaps even provide some of the minerals needed to replace those lost to tooth decay.

Prolonging the life of composite tooth fillings could be an important step forward for dental treatment, the researchers say, since more than 122 million composite tooth restorations are made in the United States every year. An average person uses their teeth for more than 600,000 "chews" a year, and some studies suggest the average lifetime of a posterior dental composite is only six years.

The new research was just published in the journal Dental Materials, in work supported by the National Institutes of Health.

"Bioactive glass, which is a type of crushed glass that is able to interact with the body, has been used in some types of bone healing for decades," said Jamie Kruzic, a professor and expert in advanced structural and biomaterials in the OSU College of Engineering.

"This type of glass is only beginning to see use in dentistry, and our research shows it may be very promising for tooth fillings," he said. "The bacteria in the mouth that help cause cavities don't seem to like this type of glass and are less likely to colonize on fillings that incorporate it. This could have a significant impact on the future of dentistry."

Bioactive glass is made with compounds such as silicon oxide, calcium oxide and phosphorus oxide, and looks like powdered glass. It's called "bioactive" because the body notices it is there and can react to it, as opposed to other biomedical products that are inert. Bioactive glass is very hard and stiff, and it can replace some of the inert glass fillers that are currently mixed with polymers to make modern composite tooth fillings.

"Almost all fillings will eventually fail," Kruzic said. "New tooth decay often begins at the interface of a filling and the tooth, and is called secondary tooth decay. The tooth is literally being eroded and demineralized at that interface."

Bioactive glass may help prolong the life of fillings, researchers say, because the new study showed that the depth of bacterial penetration into the interface with bioactive glass-containing fillings was significantly smaller than for composites lacking the glass.

Fillings made with bioactive glass should slow secondary tooth decay, and also provide some minerals that could help replace those being lost, researchers say. The combination of these two forces should result in a tooth filling that works just as well, but lasts longer.

Recently extracted human molars were used in this research to produce simulated tooth restoration samples for laboratory experiments. OSU has developed a laboratory that's one of the first in the world to test simulated tooth fillings in conditions that mimic the mouth.

If this laboratory result is confirmed by clinical research, it should be very easy to incorporate bioactive glass into existing formulations for composite tooth fillings, Kruzic said.

The antimicrobial effect of bioactive glass is attributed, in part, to the release of ions such as those from calcium and phosphate that have a toxic effect on oral bacteria and tend to neutralize the local acidic environment.

"My collaborators and I have already shown in previous studies that composites containing up to 15 percent bioactive glass, by weight, can have mechanical properties comparable, or superior to commercial composites now being used," Kruzic said.


Monday, December 21, 2015

Periodontal disease associated with increased breast cancer risk in postmenopausal women

Bottom Line: Postmenopausal women with periodontal disease were more likely to develop breast cancer than women who did not have the chronic inflammatory disease. A history of smoking significantly affected the women's risk. 


Journal in Which the Study was Published: Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research
Author: Jo L. Freudenheim, PhD, distinguished professor in the Department of Epidemiology and Environmental Health in the University at Buffalo's School of Public Health and Health Professions.
Background: Periodontal disease is a common condition that has been associated with heart disease, stroke, and diabetes. Previous research has found links between periodontal disease and oral, esophageal, head and neck, pancreatic, and lung cancers, so the researchers wanted to see if there was any relationship with breast cancer.
How the Study Was Conducted: Freudenheim and colleagues monitored 73,737 postmenopausal women enrolled in the Women's Health Initiative Observational Study, none of whom had previous breast cancer. Periodontal disease was reported in 26.1 percent of the women. Because prior studies have shown that the effects of periodontal disease vary depending on whether a person smokes, researchers examined the associations stratified by smoking status. 
Results: After a mean follow-up time of 6.7 years, 2,124 women were diagnosed with breast cancer. The researchers found that among all women, the risk of breast cancer was 14 percent higher in women who had periodontal disease. 
Among women who had quit smoking within the past 20 years, those with periodontal disease had a 36 percent higher risk of breast cancer. Women who were smoking at the time of this study had a 32 percent higher risk if they had periodontal disease, but the association was not statistically significant. Those who had never smoked and had quit more than 20 years ago had a 6 percent and 8 percent increased risk, respectively, if they had periodontal disease.
Author Comment: "We know that the bacteria in the mouths of current and former smokers who quit recently are different from those in the mouths of non-smokers," Freudenheim explained. One possible explanation for the link between periodontal disease and breast cancer is that those bacteria enter the body's circulation and ultimately affect breast tissue. However, further studies are needed to establish a causal link, Freudenheim said.
Study Limitations: Women self-reported their periodontal disease status, after being asked whether a dentist had ever told them they had it. Also, since the study focused on women who were already enrolled in a long-term national health study, they were more likely than the general population to be receiving regular medical and dental care, and were likely more health-conscious than the general population.

Friday, December 11, 2015

Build a better toothbrush: Aural feedback for oral hygiene



Researchers in Japan have discovered that how effectively we clean our teeth and how satisfied we are with the brushing job we do depends a lot on the sound of the bristles scrubbing against the enamel. In trials with volunteer teeth cleaners, the team has used a tiny microphone in a modified toothbrush to 'sample' the sound being made in the mouth during brushing and to modulate it and then feed that sound back to the volunteer via headphones to see what effect it would have on cleaning efficacy and satisfaction. They describe details in the International Journal of Arts and Technology.

Taku Hachisu and Hiroyuki Kajimoto of The University of Electro-Communications, in Chofu, Japan explain how modulating the brush sound affects brushing efficacy and satisfaction. The team found that if they manipulated the pitch, or frequency and loudness, of the brushing sound they could alter the volunteers' perception of comfort and accomplishment. They also showed that if they gradually increased the frequency as teeth cleaning progressed, the volunteers felt like the process was more comfortable and that their teeth were cleaner at the end of the process.

"Tooth brushing provides a 'negative reward' for users as they brush their teeth to avoid developing caries," the team explains. Many people find the task boring. "Subsequently, users do not consider the impact of omitting the action until suffering from caries or other dental diseases," the team adds. Their results show that it is possible to motivate users by interactively manipulating the frequency of brushing sounds, so that the task becomes more satisfying. Importantly, the system can tell, through a built-in force sensor, whether a person is brushing too hard, which can damage the gum line, and so give them aural feedback to encourage them to clean their teeth more gently.

The prototype system requires the teeth cleaner to wear headphones, which is impractical in real life. However, there are bone conduction speaker systems that might be incorporated into the smart toothbrush so that the amplified feedback loop is created in one's mouth. The team will next recruit volunteers to test the system in their comfort of their own bathrooms.


Tuesday, December 8, 2015

'No-drill' dentistry stops tooth decay


 
The white patches are signs of early decay that can be stopped and reversed before they become cavities (brown patch on tooth on the right).
Credit: University of Sydney
 
A University of Sydney study has revealed that tooth decay (dental caries) can be stopped, reversed, and prevented without the need for the traditional 'fill and drill' approach that has dominated dental care for decades.

The results of the seven year study, published today in Community Dentistry and Oral Epidemiology, found that the need for fillings was reduced by 30 to 50 per cent through preventative oral care.

"It's unnecessary for patients to have fillings because they're not required in many cases of dental decay," said the study's lead author, Associate Professor Wendell Evans of the University of Sydney.
"This research signals the need for a major shift in the way tooth decay is managed by dentists -- dental practice in Australia needs to change. Our study shows that a preventative approach has major benefits compared to current practice.

"For a long time it was believed that tooth decay was a rapidly progressive phenomenon and the best way to manage it was to identify early decay and remove it immediately in order to prevent a tooth surface from breaking up into cavities. After removing the decay, the affected tooth is then restored with a filling material -- this process is sometimes referred to as 'drilling and filling'.

"However, 50 years of research studies have shown that decay is not always progressive and develops more slowly than was previously believed. For example, it takes an average of four to eight years for decay to progress from the tooth's outer layer (enamel) to the inner layer (dentine).

"That is plenty of time for the decay to be detected and treated before it becomes a cavity and requires a filling."

Professor Wendell Evans and his team developed the Caries Management System (CMS) -- a set of protocols which cover the assessment of decay risk, the interpretation of dental X-rays, and specific treatment of early decay (decay that is not yet a cavity).

The CMS treatment 'no-drill' involves four aspects:
1. Application of high concentration fluoride varnish by dentists to the sites of early decay
2. Attention to home tooth brushing skills
3. Restriction of between-meal snacks and beverages containing added sugar
4. Risk-specific monitoring.M/ul>
"The CMS was first tested on high risk patients at Westmead Hospital with great success," said Professor Evans.
"It showed that early decay could be stopped and reversed and that the need for drilling and filling was reduced dramatically.
"A tooth should be only be drilled and filled where an actual hole-in-the-tooth (cavity) is already evident," he said.
The CMS treatment was then tested in general dental practices in New South Wales and Australian Capital Territory. The Monitor Practice Program (MPP), funded by the National Health and Medical Research Council of Australia (NHMRC), confirmed that after seven years, decay risk was substantially reduced among the CMS patients and their need for fillings was reduced by 30 to 50 per cent compared to the control group.
"The reduced decay risk and reduced need for fillings was understandably welcomed by patients," Professor Evans said. "However, patients play an important role in their treatment. This treatment will need a partnership between dentists and patients to be most successful."

Thursday, December 3, 2015

Graphene oxide could make stronger dental fillings


Graphene oxide could be used to make super strong dental fillings that don't corrode, according to a new study published in Colloids and Surfaces B: Biointerfaces.

Research suggests we chew around 800 times in an average meal; that's almost a million times a year. We put our teeth under huge strain, and often require fillings to repair them. Fillings are typically made of a mixture of metals, such as copper, mercury, silver and tin, or composites of powdered glass and ceramic.

Typical metal fillings can corrode and composite fillings are not very strong; Graphene on the other hand is 200 times stronger than steel and doesn't corrode, making it a prime new candidate for dental fillings.

In the study, researchers from Iuliu Hatieganu University of Medicine and Pharmacy, the National Institute for Research and Development of Isotopic and Molecular Technologies, and the University of Agricultural Sciences and Veterinary Medicine in Romania, and Ross University School of Veterinary Medicine Basseterre in the West Indies investigated whether different forms of graphene are toxic to teeth.

"The idea of the project was to add graphene into dental materials, in order to increase their resistance to corrosion as well as to improve their mechanical properties," explained Dr. Stela Pruneanu, one of the authors of the study from the National Institute for Research and Development of Isotopic and Molecular Technologies in Romania. "There is contradictory information regarding the cytotoxicity of graphene, so we first wanted to determine how toxic it is for teeth."

Graphene comes in different forms, including graphene oxide, nitrogen-doped graphene and thermally reduced graphene oxide. The researchers tested how toxic these different types of graphene are in vitro for stem cells found in teeth.

Thermally reduced graphene oxide was highly toxic, making it inappropriate as a dental filling material. Nitrogen-doped graphene caused membrane damage at high doses (20 and 40 micrograms per milliliter). However, it was shown to have antioxidant properties, so it could be useful if covered in a protective layer. Graphene oxide was least toxic to cells, making it an ideal candidate.

"The results were very interesting and proved that graphene is appropriate for use in dental materials," said Dr. Gabriela Adriana Filip, one of the authors of the study and Associate Professor at Iuliu Hatieganu University of Medicine and Pharmacy Cluj-Napoca in Romania. "We believe that this research will bring new knowledge about the cytotoxic properties of graphene-based materials and their potential applications in dental materials."


The next step for this research is for the team to make dental materials with graphene oxide and test how compatible they are with teeth, and how toxic they are to cells. The results are due to be published soon.




Friday, November 27, 2015

Cognitive behavior therapy can help overcome fear of the dentist


Cognitive behavioural therapy could help many people with a dental phobia overcome their fear of visiting the dentist and enable them to receive dental treatment without the need to be sedated, according to a new study by King's College London.

Anxiety about visiting the dentist is common and becomes a phobia when it has a marked impact on someone's well-being; people with dental phobias typically avoid going to the dentist and end up experiencing more dental pain, poorer oral health and a detrimental effect on their quality of life. Estimates from the most recent Adult Dental Health Survey in the UK suggest around one in ten people suffers from dental phobia.

Cognitive behavioural therapy (CBT) is a short-term therapy, typically lasting 6-10 sessions. CBT has been shown to help with a range of psychological problems, most notably for depression and anxiety-related disorders. Both cognitive and behavioural interventions have been shown to be successful in reducing dental anxiety and increasing dental attendance.

The latest study, published in the British Dental Journal, looked at the characteristics of 130 patients (99 women and 31 men) attending a psychologist-led CBT service and the outcomes of their treatment. Patients attending a clinic run by the King's College London Dental Institute Health Psychology Service at Guy's and St Thomas' NHS Foundation Trust were surveyed for their levels of dental anxiety, general anxiety, depression, suicidal thoughts, alcohol use and oral health-related quality of life.

Three-quarters of those assessed scored 19 or higher on the Modified Dental Anxiety Scale (MDAS), indicating dental phobia. The remainder all scored high on one or more items of the MDAS, suggesting a specific fear of some aspect of dentistry. Fear of dental injections and the dental drill were the most common high scoring items on the MDAS. Nearly all patients (94%) reported a knock-on effect from problems with their teeth, mouth or gums on their daily living and quality of life.

A proportion of the patients surveyed were found to have other psychological conditions - 37% had high levels of general anxiety and 12% had clinically significant levels of depression. Suicidal thoughts were reported by 12% of patients and four (3%) reported a recent intent to commit suicide. Individuals were referred to support services via the care of their GP and for suicide risk, immediate action was taken based on local service guidelines.

Of all patients referred, four-fifths (79%) went on to have dental treatment without the need for sedation and 6% had their dental treatment under sedation. The average number of CBT appointments required before a patient received dental treatment without sedation was five.

Professor Tim Newton from the Dental Institute at King's College London and lead author of the study said: "People with dental phobia are most commonly given sedation to allow them to become relaxed enough for a short period of time to have their dental treatment performed. However this does not help them to overcome their fear in the long term. The primary goal of our CBT service is to enable patients to receive dental treatment without the need for sedation, by working with each individual patient to set goals according to their priorities. Our study shows that after on average five CBT sessions, most people can go on to be treated by the dentist without the need to be sedated."

"However, there is a need for people with dental phobia to be carefully assessed by trained CBT practitioners working with dental health professionals. Some of the patients referred to us were found to be experiencing additional psychological difficulties, and needed further referral and management. CBT provides a way of reducing the need for sedation in people with a phobia, but there will still be those who need sedation because they require urgent dental treatment or they are having particularly invasive treatments. Our service should be viewed as complementing sedation services rather than as an alternative, the two together providing a comprehensive care pathway for the ultimate benefit of patients."

A recent study published in the same journal, co-authored by Professor Tim Newton, showed that more women than men reported dental phobia in the 2009 Adult Dental Health Survey. Those with dental phobia were more likely to come from a lower income background, have more caries in their teeth and suffer from poorer oral health overall


Friday, November 20, 2015

Details from the inner life of a tooth

Both in materials science and in biomedical research it is important to be able to view minute nanostructures, for example in carbon-fiber materials and bones. A team from the Technical University of Munich (TUM), the University of Lund, Charite hospital in Berlin and the Paul Scherrer Institute (PSI) have now developed a new computed tomography method based on the scattering, rather than on the absorption, of X-rays. The technique makes it possible for the first time to visualize nanostructures in objects measuring just a few millimeters, allowing the researchers to view the precise three-dimensional structure of collagen fibers in a piece of human tooth.
In principle, X-ray computed tomography (CT) has been around since the 1960s: X-ray images are taken of an object from various directions, and a computer then uses the individual images to generate a three-dimensional image of the object. Contrast is produced by the differential absorption of X-rays in dissimilar materials. However, the new method, which was developed by Franz Pfeiffer, professor for Biomedical Physics at TUM and his team utilizes the scattering of X-rays rather than their absorption. The results have now been published in the journal Nature.
Scattering provides detailed images of nanostructures
Theoretically, X-rays act like light with a very short wavelength. This principle lies at the heart of the new method: When a light is shone on a structured object, for example a CD, the reflected light produces a characteristic rainbow pattern. Although the fine grooves in the CD cannot be seen directly, the diffraction of the light rays -- known as scattering -- indirectly reveals the structure of the object.
The same effect can be observed with X-rays, and it is this phenomenon that the researchers take advantage of in their new technique. The advantage of X-rays over visible light is that they are able to penetrate into materials, thus providing detailed information about the internal structure of objects. The researchers have now combined this three-dimensional information from scattered X-rays with computed tomography (CT).
Conventional CT methods calculate exactly one value, known as a voxel, for each three-dimensional image point within an object. The new technique assigns multiple values to each voxel, as the scattered light arrives from various directions. "Thanks to this additional information, we're able to learn a great deal more about the nanostructure of an object than with conventional CT methods. By indirectly measuring scattered X-rays, we can now visualize minute structures that are too small for direct spatial resolution," Franz Pfeiffer explains.
Internal view of a tooth
For demonstration purposes the scientists examined a piece of human tooth measuring around three millimeters. A large part of a human tooth is made from the substance dentin. It consists largely of mineralized collagen fibers whose structure is largely responsible for the mechanical properties of the tooth. The scientists have now visualized these tiny fiber networks.
A total of 1.4 million scatter images were taken, with the scattered light arriving from various directions. The individual images were then processed using a specially devised algorithm that builds up a complete reconstruction of the three-dimensional distribution of the scattered rays step by step. "Our algorithm calculates the precise direction of the scatter information for each image and then forms groups having the same scatter direction. This allows internal structures to be precisely reconstructed," says Martin Bech, former postdoc at the TUM and now assistant professor at the University of Lund.
Using this method, it was possible to clearly view the three-dimensional orientation of the collagen fibers within a sample of this size for the first time. The results are in agreement with knowledge previously obtained about the structures from thin sections. "A sophisticated CT method is still more suitable for examining large objects. However, our new method makes it possible to visualize structures in the nanometer range in millimeter-sized objects at this level of precision for the first time," says Florian Schaff, lead author of the paper.

Journal Reference:
  1. Florian Schaff, Martin Bech, Paul Zaslansky, Christoph Jud, Marianne Liebi, Manuel Guizar-Sicairos, Franz Pfeiffer. Six-dimensional real and reciprocal space small-angle X-ray scattering tomography. Nature, 2015; 527 (7578): 353 DOI: 10.1038/nature16060

Tuesday, November 17, 2015

How to eliminate pain tied to tooth decay



This is a scanning electron microscope image of newly grown enamel using amelogenin-chitosan hydrogel.

CREDIT

Herman Ostrow School of Dentistry of USC
Dual discoveries at USC propose a promising method to regrow nonliving hard tissue, lessening or even eliminating pain associated with tooth decay, which the National Institutes of Health calls the most prevalent chronic disease.
Janet Moradian-Oldak, a professor at the Herman Ostrow School of Dentistry of USC, has investigated methods to regrow tooth enamel for the past two decades. The process is especially tricky because unlike bone, mature enamel cannot rejuvenate. Tooth enamel is a nonliving tissue.
The a-ha moment came Oct. 22 when, in collaboration with lead author Sauma Prajapati of USC and other colleagues, she published a study in the Biomaterials journal saying matrix metalloproteinase-20, an enzyme found only in teeth, chops up amelogenin proteins, which facilitate organized enamel crystal formation. MMP-20 clears the way for hard material to usurp vacated space.
Her team is the first to define the function of an enzyme for preventing protein occlusion inside a crystal, she said.
"MMP-20 is released at a very early stage of enamel formation," said Moradian-Oldak, the study's senior author. "MMP-20 chops up proteins during the crystallization of enamel. Together with other enzymes, it gets rid of 'sludge' so the enamel making cells in the body can add more mineral and make enamel, the hardest bioceramic in the human body."
Dental restoration
Moradian-Oldak will couple the MMP-20 discovery with another study published Nov. 2 in the Journal of Biomedical Engineering and Informatics, which concluded an amelogenin-chitosan hydrogel could repair early tooth decay by growing an enamel-like layer that reduces lesions by up to 70 percent.
"Recognizing MMP-20's function in biomineralization is one of the first steps to learning how dental enamel forms in nature," said Qichao Ruan, lead author of the hydrogel study and a postdoctoral research associate in the Center for Craniofacial Molecular Biology at USC. "The findings regarding MMP-20 not only help us to further understand the mechanisms of enamel formation but [they] also can be applied in the design of novel biomaterials for future clinical applications in dental restoration or repair."
The Food and Drug Administration has not yet approved any type of enamel regrowing gel. USC is in pre-clinical trials. Moradian-Oldak said one day people may be able to use an overnight mouth guard or teeth strips saturated with hydrogel to regrow enamel-like substances and reduce teeth sensitivity.
Finding the right fix
Products such as toothpaste and mouthwash containing fluoride and casein phosphopeptide-amorphous calcium phosphate promote remineralization of initial enamel lesions; however, they need to be used regularly and are more of a tire patch than a real solution, Moradian-Oldak said. It plugs up the problem so people don't feel pain. The gel, however, fills the cracks and holes with an enamel-like substance.
In the United States, 92 percent of adults aged 20 to 64 have had dental decay in their permanent teeth, Moradian-Oldak said. Grinding teeth at night, gum recession and the disappearance of enamel over a lifetime due to demineralizing acidic food and drink are all common problems people everywhere face.
When tested in an environment that mimics an oral cavity's biochemical processes, the gel created a robust attachment, eliminating the threat of secondary cavities in the same spot, Ruan said. The gel could be more effective than traditional crowns, whose adhesion weakens over time, he added.
"Besides biocompatibility and biodegradability, the gel has unique antimicrobial and adhesion properties that are important for dental applications," Ruan said.

Monday, November 9, 2015

Watching cement dry could help dental fillings last longer

This shows typical dental glass cement, a UK innovation. It is made from glass powder, liquid polymer and water, and is the preferred non-toxic choice to mercury amalgam, which has been used for filling teeth for almost 200 years.

CREDIT

Semmelweis University Dental School
Scientists led by Queen Mary University of London (QMUL) and Aberystwyth University have revealed 'sweet points' for dental fillings, where cement used to fill cracks regain elasticity before hardening indefinitely. This could have implications for creating more durable and longer-lasting fillings in the future. 
Typical dental glass cement, a UK innovation, is made from glass powder, liquid polymer and water, and is the preferred non-toxic choice* to mercury amalgam, which has been used for filling teeth for almost 200 years. 
Publishing in the journal Nature Communications, the team used nano-level dentistry to measure how cement sets in real-time. 
They looked at the surface between the hard glass particles and surrounding polymer as the strength of the cement develops.
Guided by computer models, they used intense beams of neutrons from the Science and Technology Facilities Council's (STFC) neutron and muon source, to find that dental cement sets in fits and starts rather than hardening continuously. The findings identify 'sweet points' in time: when the cement starts to approach the toughness of the tissue that our teeth are made of and occur in first 12 hours of setting. 
Co-author Dr Gregory Chass from QMUL's School of Biological and Chemical Sciences explains: 
"Most of us have fillings in our teeth and know that a crack means a trip to the dentist for a replacement. 
"Our works opens up the possibility of tailoring the strength of non-mercury cements by homing in on the special setting points, which we call 'sweet points', to make environmentally-friendly dental fillings that not only last longer but could prevent further tooth decay."
Understanding 'sweet points' of dental cement could lead to better applications of fillings and easier treatment options for patients.
Co-author Professor Neville Greaves from the Department of Physics at Aberystwyth University said: 
"Dental fillings are really complex materials. Using neutrons we have discovered how mechanical toughness develops, element by element. This is fundamental physics in action for the general good."
The findings could have implications for other industries that use cement, such as construction, and to test toughness in other materials.
Andrew Taylor, Executive Director of STFC's National Laboratories, said: 
"It is always gratifying to see outcomes such as this coming from science at STFC's facilities and in this case, our neutron and muon source. Neutrons have such a broad range of applications and are used by scientists looking at everything from stresses and strains in plane wings to progressing methods to producing more effective antibiotics. 
"We can see here how a fundamental technique is applied to an everyday issue that we can all identify with."

Friday, November 6, 2015

Dental implants frequently lead to complications


Almost 8 percent of patients experience loss of at least one implant within ten years. Even more develop peri-implantitis. Patients with periodontitis run a greater risk of both implant loss and peri-implantitis. A doctoral thesis at Sahlgrenska Academy has explored the various issues.

Approximately 30,000 Swedes receive dental implant therapy every year. The method is common in connection with partial or full edentulism (toothlessness), and Sweden is among the countries with the most dental implants per capita.

Biological complications

Previous evaluations have frequently been limited to observational studies of patient populations in specialist dental care. Few attempts have been made to analyze biological complications such as peri-implantitis, which is characterized by inflammation in adjacent tissues and loss of supporting jawbone.

A national project evaluated the therapy in terms of patient-reported outcomes, implant loss and prevalence of peri-implantitis.

High degree of satisfaction

"The results of the initial questionnaire survey, which included 4,716 randomly selected patients, indicated a high degree of satisfaction, particularly among men and older respondents," says Jan Derks, researcher at Sahlgrenska Academy.

Developed peri-implantitis

A total of 596 patients at 37 Swedish clinics were examined at a 9-year follow-up.

"Altogether, 7.6 % of patients had lost at least one implant and 14.5 % had developed peri-implantitis with pronounced bone loss," Dr. Derks says.

Patients suffering from periodontitis exhibited an increased risk of severe peri-implantitis, while both periodontitis and smoking were associated with early implant loss.

Progresses quickly

"Peri-implantitis appears to develop within a few years and then progresses quickly and at an accelerating pace," Dr. Derks says.

The results of the study provide crucial input to both patients and dental practitioners in the effort to minimize the risk of implant loss and peri-implantitis.

Thursday, November 5, 2015

Preventing dental implant infections


One million dental implants are inserted every year in Germany, and often they need to be replaced due to issues such as tissue infections caused by bacteria. In the future, these infections will be prevented thanks to a new plasma implant coating that kills pathogens using silver ions.
Bacterial infection of a dental implant is a dreaded complication, as it carries with it a high risk of jawbone degeneration. Implanting an artificial dental root sets off a race between infectious pathogens and the body's own cellular defenses. If the bacteria win, they form a biological film over the titanium to protect themselves from anti-biotics. Once the implant is colonized by germs, the result is an inflammatory reaction, which can result in bone atrophy.

To lower the risk of infection and improve the long-term effectiveness of the implant, researchers at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen have developed a new type of implant coating in cooperation with industry partners. The DentaPlas coating helps prevent the growth of bacteria, thus allowing the implant to properly take hold and thereby form a faster and more permanent bond with the jawbone. The trick to this lies in combining surface materials that feature physical as well as chemical properties. "We have given the DentaPlas coating a rough texture, which promotes cellular growth, in addition to combining it with a hydrophilic plasma polymer coating, which attracts moisture," says Dr. Ingo Grunwald, project manager at the IFAM. Researchers have integrated silver nanoparticles into the thin plasma polymer coating, which is up to just 100 nanometers thick. The silver nanoparticles dissolve over a period of several weeks, and during that time they continuously release small quantities of anti-microbial silver ions, which kill bacteria.

Three layers of protection

"The DentaPlas system consists of three layers, with two plasma polymer layers surrounding a center layer of silver. Within this structure a biocide reservoir is formed, and the outermost layer releases the ions. This is beneficial because it prevents direct contact between the tissue and the silver particles, which can be toxic when exposed," says developer Dr. Dirk Salz. Researchers can tailor the silver concentration as well as the thickness of the layers and their porosity. This allows the silver ions to penetrate the outermost plasma polymer layer over a set period of time deemed necessary to properly integrate the implant. When the silver reservoir is exhausted, no more silver ions are released, thus avoiding any long-term toxic effects.

In trials using finished implants and titanium test samples, the IFAM researchers demonstrated that the DentaPlas coating is not only anti-microbial but also fully biocompatible and sterilizable. The test samples were coated using a plasma polymerization facility at the IFAM in Bremen. Researchers confirmed the mechanical stability and robustness of the DentaPlas coating in trials using the lower jawbones of pigs taken from butcher shops. Here, they subjected the DentaPlas coated implants to the rigors of being screwed into place using the instruments found in modern dental practices. The DentaPlas coating passed this stress test with flying colors. Project partner and Fraunhofer spinoff Bio Gate AG successfully transferred the processes of coating the test samples and titanium screws to its own production facilities. The medical tech-nology company is also the manufacturer of the DentaPlas three-layer coating system.

Wednesday, October 21, 2015

Diamonds -- a tooth's best friend?


Gold, silver and porcelain are among the many materials dentists can use to fix damaged teeth. Soon diamonds -- at least tiny, microscopic ones -- could be added to that list. Scientists have developed a new material with nanodiamonds that has the potential to improve current root canal therapies and help prevent future infection. Their report appears in the journal ACS Nano.

Millions of Americans undergo root canals every year to clear out damaged or infected pulp, the soft part in the middle of a tooth. Dentists' current go-to material to fill the space left behind is a rubber compound called gutta-percha. In some cases, however, a patient's tooth can get re-infected, which calls for another treatment. To prevent this from happening, researchers have been exploring other fillers, including nanodiamonds, which are robust and can be modified with antimicrobial drug compounds. So Dean Ho and colleagues decided to develop a potential root canal therapy based on them.

The team combined nanodiamonds, gutta-percha and amoxicillin, a broad-spectrum antibiotic, into a new material. Lab testing showed it was stronger than gutta-percha by itself and was effective at killing Staphylococcus aureus, which is one of the bacteria responsible for root canal re-infections. The scientists say future studies will check whether the composite works in clinical practice.


Monday, September 14, 2015

Smokers at higher risk of losing their teeth, research shows


A new study has confirmed that regular smokers have a significantly increased risk of tooth loss.

Male smokers are up to 3.6 times more likely to lose their teeth than non-smokers, whereas female smokers were found to be 2.5 times more likely.

The research, published in the Journal of Dental Research, is the output of a long-term longitudinal study of the EPIC Potsdam cohort in Germany carried out by researchers at the University of Birmingham and the German Institute of Human Nutrition.

Tooth loss remains a major public health problem worldwide. In the UK, 15% of 65-74 year olds and over 30% of 75+ year olds are edentate (have lost all of their natural teeth). Globally, the figure is closer to 30% for 65-74 year olds.

Lead author Professor Thomas Dietrich, from the University of Birmingham, explained, "Most teeth are lost as a result of either caries (tooth decay) or chronic periodontitis (gum disease). We know that smoking is a strong risk factor for periodontitis, so that may go a long way towards explaining the higher rate of tooth loss in smokers."

Smoking can mask gum bleeding, a key symptom of periodontitis. As a result, the gums of a smoker can appear to be healthier than they actually are.

Professor Dietrich added, "It's really unfortunate that smoking can hide the effects of gum disease as people often don't see the problem until it is quite far down the line. The good news is that quitting smoking can reduce the risk fairly quickly. Eventually, an ex-smoker would have the same risk for tooth loss as someone who had never smoked, although this can take more than ten years."

Kolade Oluwagbemigun, from the German Institute of Human Nutrition, said, "Gum disease and consequential tooth loss may be the first noticeable effect on a smoker's health. Therefore, it might give people the motivation to quit before the potential onset of a life-threatening condition such as lung disease or lung cancer."

The findings were independent of other risk factors such as diabetes, and are based on data from 23,376 participants which aimed to evaluate the associations between smoking, smoking cessation and tooth loss in three different age groups.

The association between smoking and tooth loss was stronger among younger people than in the older groups. In addition, the results clearly demonstrated that the association was dose-dependent; heavy smokers had higher risk of losing their teeth than smokers who smoked fewer cigarettes.

Professor Heiner Boeing, also from the German Institute of Human Nutrition, added, "In addition to the many noted benefits for cardiovascular health, and risk of lung disease and cancer, it is clear that dental health is yet another reason not to take up smoking, or to quit smoking now."

Friday, September 4, 2015

Supervised tooth brushing and floride varnish schemes benefit kids and the health economy


Action to prevent tooth decay in children, such as supervised tooth brushing and fluoride varnish schemes, are not just beneficial to children's oral health but could also result in cost savings to the NHS of hundreds of pounds per child, so says a leading dental health researcher.

Professor Elizabeth Kay, Foundation Dean of the Peninsula Dental School from Plymouth University Peninsula Schools of Medicine and Dentistry, has carried out the first economic evaluation of public health measures to reduce tooth decay in children at high risk, in association with the National Institute for Health and Care Excellence (NICE) and the York Health Economic Consortium. She will present her findings at this year's British Society for Oral and Dental Research Annual Meeting in Cardiff, 14th to 16th September.

Almost 26,000 children a year aged between five and nine are admitted to hospital for dental treatment under general and local anaesthetic in the UK, for conditions which are on the whole preventable through better understanding and adoption of good oral health routines.

In her study Professor Kay found that, taking the threshold value used by NICE of £20,000 per Quality Adjusted Life Year (QALY), preventive schemes targeted at high risk children would be considered to be cost-effective even if they cost £46 per year per child for tooth brushing or £62 per child per year for fluoride varnish schemes. This would represent a saving of hundreds of pounds per child when compared with the cost of surgical treatments in hospital.

QALY is used in assessing the value for money of a medical intervention.

The model showed that for children at high risk of oral disease, supervised brushing and fluoride varnish schemes are cost-effective options.

Said Professor Kay: "We have more work to do here to translate the results of our study into policy, but I must stress that this is about more than making better use of NHS funds, and demonstrating that oral health promotion programmes offer extremely good value for money. I think it is a national outrage that so many children in the UK are admitted to hospital for surgical procedures for conditions which are by and large preventable. If there was a health issue that resulted in this number of children having another body part removed under general or local anaesthetic there would be a justifiable national outcry, yet for many reasons tooth extraction appears to have become accepted in some circles. This study demonstrates that it is also economically viable and sensible to prevent tooth decay"

She added: "By showing sound economic reasons for increasing the use of preventative measures, such as tooth brushing and fluoride varnishing, I hope that they can now compete for resource against other less cost-effective interventions."

Thursday, August 13, 2015

Dentists tapped for new role: Drug screenings

A visit to the dentist has the potential to be more than a checkup of our teeth as patients are increasingly screened for medical conditions like heart disease and diabetes. A new study by researchers at Columbia University's Mailman School of Public Health focuses on dental screenings for drug misuse, finding 77 percent of dentists ask patients about illicit drug use, and 54 percent of dentists believe that such screenings should be their responsibility. Results of the study are online in the journal Addiction.
"There are a sizeable number of people whose visit to a dentist represents their sole interaction with the healthcare system, highlighting the significance of the dental visit as a key opportunity to identify substance use disorders," said Carrigan Parish, DMD, associate research scientist in the Department of Sociomedical Sciences. "However, our findings underscore a significant barrier in dentists' attitudes that may limit the potential of the dental venue to play a role in screening for substance misuse."
The researchers, led by Lisa Metsch, PhD, principal investigator and Stephen Smith Professor and chair of the Department of Sociomedical Sciences, sampled 1,802 U.S. dentists in general practice from a nationally representative survey by the American Dental Association Survey Center conducted from 2010 to 2011. The survey achieved a very high response rate of 71 percent, increasing the ability of the survey results to capture a complete picture of the U.S. dental workforce. According to Metsch, "there is an increasing recognition about the need to better integrate oral and systemic health," and "questions remain about the feasibility of offering preventive screening and testing alongside dental care--many of which are being answered in this study."
Those dentists who embraced substance misuse screening as part of their professional role were more likely to query about misuse with their patients (86 percent) compared with those who did not accept such screenings as their responsibility (68 percent). In general, both agreement with the purpose of and use of health history forms with substance misuse questions increased with the amount of prior training and knowledge regarding substance use. 
Older dentists were less likely to report that their health history form included questions about substance misuse than those who were younger. Dentists under the median age of 53 were also more apt to say that illicit drug use screening should be part of the dentist's role than their more senior counterparts (62 percent versus 47 percent). As with age, agreement with screening as part of dentists' role and health history form screening increases markedly with how recently the dentist graduated.
Gender was also associated with dentists' attitudes toward screenings. More female dentists (61 percent) than their male counterparts (52 percent) agreed that illicit drug use screening should be the role of the dentist. 
Drug use can have a negative impact on dental health as well as overall health. Patterns of oral health pathology attributed to methamphetamine users, for example, include rampant tooth decay, accelerated tooth wear, unexplained advanced gum disease, missing multiple teeth, and overall detrimental dental effects that are rapid and severe. These patients also often seek cosmetic dental treatment, such as veneers and whitening, which give dentists another opportunity to discuss suspected substance misuse, provide referrals for treatment, and encourage cessation of drug misuse. 
Furthermore, dentists are the second-largest group of prescribers of opioid pain medication. "Because dental care routinely involves treating pain and emergencies, dentists may encounter substance-seeking patients who complain of pain more severe than anticipated based on the nature of their dental condition, who report lost prescriptions for opioid pain medications, or who only seek dental treatment sporadically," noted Parish. 
"In order for substance misuse screening to be compatible with the dental setting, two-way communication between patient and dentist needs to occur more openly," observed Parish. "While surveys have shown that patients are amenable to receiving medical screenings by dentists 'chair-side' for such conditions as HIV, heart disease, and diabetes, further studies directly addressing patient attitudes on substance misuse screening are key in determining patients' acceptance of such services." Dentists may also need additional education to increase their awareness, comfort, and knowledge of substance misuse, given that "dentists are well situated to make appropriate referrals to treatment centers if instilled with the proper training and supports."


Monday, August 10, 2015

JDR articles discuss diet, dental caries and health policy


Today, the International and American Associations for Dental Research (IADR/AADR) published two reports including a critical review titled "Diet and Dental Caries - the Pivotal Role of Free Sugars Reemphasized." In this study, authors Aubrey Sheiham, University College London, England; and W. Philip James, London School of Hygiene and Tropical Medicine, England, demonstrate the sensitivity of cariogenesis (the development of caries) to even very low sugars intakes. In this critical review, the authors reviewed the literature on the role of sucrose in the cariogenic process and conclude there is extensive scientific evidence that free sugars are the primary necessary factor in the development of dental caries.

This year, the World Health Organization (WHO) published a guideline on sugars intake for adults and children. The objective of the WHO guideline is to provide recommendations on intakes of free sugars to reduce risks of NCDs in adults and children, with a particular focus on the prevention and control of unhealthy weight gain and dental caries. WHO recognized that dental diseases are the most prevalent noncommunicable diseases globally and the treatment of dental diseases is expensive, and would exceed the entire financial resources available for the health care of children in most lower income countries. In this guideline, WHO recommends reducing the intake of free sugars to less than 10% of total energy intake.

A dose-response relationship between the sucrose or its monosaccharide intakes and the progressive life-long development of caries was demonstrated. This situation results in a substantial dental health burden throughout life.

Beau Meyer and Jessica Lee, The University of North Carolina at Chapel Hill, USA, commented on these findings in a perspective article titled "The Confluence of Sugar, Dental Caries and Health Policy". In this paper Meyer and Lee underscore the relationship between sugars intake and dental caries, and implications for health policy interventions. They emphasize that as policies surrounding limiting sugar intake continue to evolve, attention must be given to how best to put these policies into practice to produce positive behavior change that ultimately should lead to improved oral health outcomes.

Monday, May 11, 2015

For children with autism, adjusting the environment to be more soothing could eliminate the need for general anesthesia to cope with routine dental cleanings


Going to the dentist might have just gotten a little less scary for the estimated 1 in 68 U.S. children with autism spectrum disorder as well as children with dental anxiety, thanks to new research from USC.

In an article published on May 1 by the Journal of Autism and Developmental Disorders, researchers from USC and Children's Hospital Los Angeles (CHLA) examined the feasibility of adapting dental environments to be more calming for children with autism spectrum disorder.

"The regular dental environment can be quite frightening for children with autism who, not knowing how to react, tend to be completely averse to whatever we're trying to do," said one of the study's authors, José Polido DDS, head of dentistry at CHLA and assistant professor at the Herman Ostrow School of Dentistry of USC.

Children with autism spectrum disorders -- as well as some typically developing children -- often show heightened responses to sensory input and find these sensations uncomfortable. As such, the dental office, with its bright lights, loud sounds from the dental equipment, and touch of children in and around the mouth, present particular challenges for such children.

In the study, 44 CHLA patients -- 22 with autism and 22 "typically developing" (defined as children not on the autism spectrum)--underwent two professional dental cleanings. One cleaning took place in a regular dental environment, the other in a sensory adapted dental environment. During each session, the child's physiological anxiety, behavioral distress and pain intensity were measured.

"I've talked to several parents who have said, 'We really put off taking our child to the dentist because we know how hard it is and we know he's going to scream and cry,'" said Sharon Cermak, the study's lead author and professor at the USC Mrs. T.H. Chan Division of Occupational Science and Occupational Therapy, as well as professor of pediatrics at the Keck School of Medicine of USC.

To help combat that reaction, researchers adapted the dental environments by turning off overhead office lights and headlamps, projecting slow-moving visual effects onto the ceiling and playing soothing music.

Instead of using traditional means to secure the child in the dental chair, practitioners used a seat cover that looked like a gigantic butterfly whose wings wrapped around the child and provided a comforting, deep-pressure hug.

The research team found that both children who are typically developing as well as those with autism spectrum disorders exhibited decreased psychological anxiety and reported lower pain and sensory discomfort in the sensory-adapted dental environment.

The study -- which represents a unique collaboration between pediatric dentists and occupational therapists--could help improve oral health care for children with autism -- a group reported to suffer from poor oral health, research shows.

The findings could also represent a cost savings to the health care system, with fewer insurance reimbursements paid to dental offices for the additional staff members and general anesthesia often necessary for children with autism.

Next up for the researchers is to increase their sample size -- they'll be using 110 children in each group -- to determine which factors (e.g. age, anxiety, sensory over-responsitivity) best predict which children respond best to the intervention.

"One of our long-term goals with this study is to help dentists develop protocols for their own dental clinics to see how sensory components are contributing to behavioral issues," Cermak said. "I think these protocols can then be translated across the globe."

Thursday, May 7, 2015

Arginine, amino acid, could improve oral health


Arginine, a common amino acid found naturally in foods, breaks down dental plaque, which could help millions of people avoid cavities and gum disease, researchers at the University of Michigan and Newcastle University have discovered.

Alexander Rickard, assistant professor of epidemiology at the U-M School of Public Health, and colleagues, discovered that in the lab L-arginine -- found in red meat, poultry, fish and dairy products, and is already used in dental products for tooth sensitivity--stopped the formation of dental plaque.

"This is important as bacteria like to aggregate on surfaces to form biofilms. Dental plaque is a biofilm," Rickard said. "Biofilms account for more than 50 percent of all hospital infections. Dental plaque biofilms contribute to the billions of dollars of dental treatments and office visits every year in the United States."

Dental biofilms are the culprits in the formation of dental caries (cavities), gingivitis and periodontal disease. Surveys indicate that nearly 24 percent of adults in the United States have untreated dental caries, and about 39 percent have moderate-to-severe periodontitis, a number that rises to 64 percent for those over age 65.

Most methods for dental plaque control involve use of antimicrobial agents, such as chlorhexidine, which are chemicals aimed at killing plaque bacteria, but they can affect sense of taste and stain teeth. Antimicrobial treatments have been the subject of debate about overuse in recent years.

Pending further clinical trials to verify their lab findings, the researchers said L-arginine could take the place of the current plaque-controlling biocide substances including chlorhexidine and other antimicrobials.

"At present, around 10-to-15 percent of adults in the Western world have advanced periodontitis, which can lead to loose teeth and even the loss of teeth. Therefore, there is a clear need for better methods to control dental plaque," said Nick Jakubovics, a lecturer at Newcastle University's School of Dental Sciences.

Their findings are reported in the current issue of PLOS ONE.

The mechanism for how L-arginine causes the disintegration of the biofilms needs further study, the researchers said. It appears arginine can change how cells stick together, and can trigger bacteria within biofilms to alter how they behave so that they no longer stick to surfaces, they said.

In conducting their research, team members used a model system they introduced in 2013 that mimics the oral cavity. The researchers were able to grow together the numerous bacterial species found in dental plaque in the laboratory, using natural human saliva.

"Other laboratory model systems use one or a small panel of species," Rickard said. "Dental plaque biofilms can contain tens to hundreds of species, hence our model better mimics what occurs in the mouth, giving us great research insight."

Tuesday, May 5, 2015

Treating gum disease reduces prostate symptoms


Treating gum disease reduced symptoms of prostate inflammation, called prostatitis, report researchers from Case Western Reserve University School of Dental Medicine and the Departments of Urology and Pathology at University Hospitals Case Medical Center.

Previous studies have found a link between gum disease and prostatitis, a disease that inflames the gland that produces semen. Inflammation can make urination difficult.

"This study shows that if we treat the gum disease, it can improve the symptoms of prostatitis and the quality of life for those who have the disease," said Nabil Bissada, chair of Case Western Reserve's Department of Periodontics and the new study's corresponding author.

The researchers reported their findings in the Dentistry article, "Periodontal Treatment Improves Prostate Symptoms and Lowers Serum PSA in Men with High PSA and Chronic Periodontitis." Naif Alwithanani, a graduate student in the dental school, led the investigation as part of his residency in periodontics.

Bissada explained that gum disease not only affects the mouth, but is a system-wide condition that can cause inflammation in various parts of the body. The dental school has previously found a link between gum disease and fetal deaths, rheumatoid arthritis and heart disease.

The new prostate study

Researchers studied 27 men, 21 years old and older. Each had had a needle biopsy within the past year that confirmed inflammation of the prostate gland, and a blood test that showed elevated prostate specific antigen (PSA) levels--possible signs of inflammation and cancer.

The men were assessed for symptoms of prostate disease by answering questions on the International-Prostate Symptom Score (IPSS) test about their quality of life and possible urination issues.

Researchers found 21 of the 27 participants had no or mild inflammation, but 15 had biopsy-confirmed malignancies. Two had both inflammation and a malignancy.

The men also had to have at least 18 teeth and were examined for signs of gum disease, such as increased levels of inflammation and bleeding and/or loose teeth due to attachment and bone loss.

All the men had moderate to severe gum disease, for which they received treatment. They were tested again for periodontal disease four to eight weeks later and showed significant improvement.

During the periodontal care, the men received no treatment for their prostate conditions. But even without prostate treatment, 21 of the 27 men showed decreased levels of PSA. Those with the highest levels of inflammation benefited the most from the periodontal treatment. Six participants showed no changes.

Symptom scores on the IPSS test also showed improvement.

Bissada is now conducting follow-up research to support the first study's findings. He hopes to make periodontal treatment a standard part of treating prostate disease, much like cardiac patients are often encouraged to visit their dentist before undergoing heart procedures and a dental checkup is advised for women who are pregnant or considering pregnancy.

Thursday, April 16, 2015

The connection between mouth bacteria and inflammation in heart disease


Oral infections are the most common diseases of mankind and are also a key risk factor for heart disease, which is the leading cause of death worldwide. In a review article published in Trends in Endocrinology and Metabolism on April 16, researchers summarize the latest clinical evidence supporting a link between oral infections, which are caused by the bacteria in our mouth, and heart disease, and they emphasize the important role of inflammation in both of these conditions.

"Given the high prevalence of oral infections, any risk they contribute to future cardiovascular disease is important to public health," says senior author Thomas Van Dyke of the Forsyth Institute. "Unravelling the role of the oral microbiome and inflammation in cardiovascular disease will likely lead to new preventive and treatment approaches." The (oral) microbiome refers to the totality of microorganisms in a body part-in this case the mouth--that we all co-exist with.

The most common oral infections are cavities and periodontal diseases such as gingivitis and periodontitis, which are chronic inflammatory diseases that slowly and steadily destroy the supporting structures of multiple teeth. Significant epidemiological evidence supports an association between oral infections, particularly periodontitis, and stroke, especially among men and younger individuals.

Inflammation plays a major role both in oral infections such as periodontitis and in cardiovascular disease. However, over-the-counter nonsteroidal anti-inflammatory drugs such as ibuprofen can produce significant cardiovascular side effects, which means it is crucial that we consider alternative therapies. A high dose of a commonly prescribed cholesterol-lowering medication, atorvastatin, which boosts blood levels of anti-inflammatory molecules called lipoxins and resolvins, prevents both periodontal and cardiovascular inflammation and reverses existing disease in humans. This is exciting and promising because lipoxins and resolvins also have the advantage of naturally controlling inflammation without suppressing the immune system.

"New discoveries of natural pathways that resolve inflammation have offered many opportunities for revealing insights into disease pathogenesis and for developing new pharmacologic targets for the treatment of both oral infections and cardiovascular disease," Van Dyke says.

In future studies, it will be important to compare the effectiveness of these inflammation-reducing molecules, which we produce naturally, and other interventions that could potentially prevent or reverse periodontitis and cardiovascular disease. Another open question is whether there is a reverse relationship between these conditions: what if the onset of cardiovascular disease influences the presence or progression of periodontal disease? Or what are some of the common genetic mechanisms underlying periodontitis and cardiovascular disease?

In the meantime, Van Dyke recommends that people take better care of their teeth to potentially lower their risk of cardiovascular disease and other health problems. "The majority of diseases and conditions of aging, including obesity and type 2 diabetes, have a major inflammatory component that can be made worse by the presence of periodontitis," he says. "Periodontitis is not just a dental disease, and it should not be ignored, as it is a modifiable risk factor."

###

Trends in Endocrinology & Metabolism, Kholy et al.:"Oral infections and cardiovascular disease" http://dx.doi.org/10.1016/j.tem.2015.03.001

Tuesday, April 14, 2015

How gum disease treatment can prevent heart disease


A new study from the Forsyth Institute is helping to shed more light on the important connection between the mouth and heart. According to research recently published online by the American Heart Association, scientists at Forsyth and Boston University have demonstrated that using an oral topical remedy to reduce inflammation associated with periodontitis, more commonly known as gum disease, also results in the prevention of vascular inflammation and can lower the risk of heart attack.

This study is the first time researchers anywhere have demonstrated the ability of an oral treatment for gum disease to also reduce inflammation in the artery wall. The active ingredient is an inflammation resolving molecule, known as Resolvin E1. This discovery further underscores the increasing body of evidence showcasing how problems in the mouth - and how they are treated - can have life changing influences on other key systems in the body, such as the heart in this case.

"Our research is helping to underscore the very real link between oral health and heart disease," said Lead Investigator Hatice Hasturk, DDS, PhD, an associate member of Forsyth's Department of Applied Oral Sciences and director of Forsyth's Center for Clinical and Translational Research. "The general public understands the connection between heart health and overall wellness, and often takes appropriate steps to prevent heart disease. More education is needed to elevate oral wellness into the same category in light of proven connections to major health conditions."

According to the CDC, heart disease accounts for one in four deaths in the United States, and the rate continues to rise. Forsyth's findings suggest a need to expand the public's understanding of risk factors beyond cholesterol, smoking, hypertension and diabetes to include a focus on oral health. With support from the scientific community, Forsyth aims to generate greater awareness of gum disease (affecting 64.7 million American adults according to the CDC) as a critical risk factor for heart disease, independent from diet and lifestyle.

The study, titled, "Resolvin E1 Prevents Atheromatous Plaque Formation," will be published in print in the May issue of Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB), a journal of the American Heart Association. It is the first paper to show a rabbit model of accelerated heart disease, demonstrating a range of atherosclerotic plaque stages that more closely resemble those in humans without genetic modification of the animal. This research is authored by Hatice Hasturk, Rima Abdallah, Alpdogan Kantarci, Daniel Nguyen, Nicholas Giordano, James Hamilton and Thomas E. Van Dyke.

Wednesday, April 1, 2015

A novel way to apply drugs to dental plaque


Therapeutic agents intended to reduce dental plaque and prevent tooth decay are often removed by saliva and the act of swallowing before they can take effect. But a team of researchers has developed a way to keep the drugs from being washed away.

Dental plaque is made up of bacteria enmeshed in a sticky matrix of polymers--a polymeric matrix--that is firmly attached to teeth. The researchers, led by Danielle Benoit at the University of Rochester and Hyun Koo at the University of Pennsylvania's School of Dental Medicine, found a new way to deliver an antibacterial agent within the plaque, despite the presence of saliva.

Their findings have been published in the journal ACS Nano.

"We had two specific challenges," said Benoit, an assistant professor of biomedical engineering. "We had to figure out how to deliver the anti-bacterial agent to the teeth and keep it there, and also how to release the agent into the targeted sites."

To deliver the agent--known as farnesol--to the targeted sites, the researchers created a spherical mass of particles, referred to as a nanoparticle carrier. They constructed the outer layer out of cationic--or positively charged--segments of the polymers. For inside the carrier, they secured the drug with hydrophobic and pH-responsive polymers.

The positively-charged outer layer of the carrier is able to stay in place at the surface of the teeth because the enamel is made up, in part, of HA (hydroxyapatite), which is negatively charged. Just as oppositely charged magnets are attracted to each other, the same is true of the nanoparticles and HA. Because teeth are coated with saliva, the researchers weren't certain the nanoparticles would adhere. But not only did the particles stay in place, they were also able to bind with the polymeric matrix and stick to dental plaque.

Since the nanoparticles could bind both to saliva-coated teeth and within plaque, Benoit and colleagues used them to carry an anti-bacterial agent to the targeted sites. The researchers then needed to figure out how to effectively release the agent into the plaque.

A key trait of the inner carrier material is that it destabilizes at acidic--or low pH--levels, such as 4.5, allowing the drug to escape more rapidly. And that's exactly what happens to the pH level in plaque when it's exposed to glucose, sucrose, starch, and other food products that cause tooth decay. In other words, the nanoparticles release the drug when exposed to cavity-causing eating habits--precisely when it is most needed to quickly stop acid-producing bacteria.

The researchers tested the product in rats that were infected with Streptococcus mutans--a microbe that causes tooth decay. "We applied the test solutions to rats' mouths twice daily for 30 seconds, simulating what a person might do using a mouth rinse morning and night," said Hyun Koo, a professor in the Department of Orthodontics and co-senior author of the work. "When the drug was administered without the nanoparticle carriers, there was no effect on the number of cavities and only a very small reduction in their severity. But when it was delivered by the nanoparticle carriers, both the number and severity of the cavities were reduced."

Plaque formation and tooth decay are chronic conditions that need to be monitored through regular visits to the dental office. The researchers hope their results will someday lead to better--and perhaps permanent--treatments for dental plaque and tooth decay, as well as other biofilm-related diseases.

Monday, March 16, 2015

Inflammation in mouth, joints in rheumatoid arthritis



At the 93rd General Session and Exhibition of the International Association for Dental Research, researcher Sheila Arvikar, Massachusetts General Hospital, Boston, USA, will present a study titled "Inflammation in the Mouth and Joints in Rheumatoid Arthritis." The IADR General Session is being held in conjunction with the 44th Annual Meeting of the American Association for Dental Research and the 39th Annual Meeting of the Canadian Association for Dental Research.


Periodontitis shares pathogenic mechanisms with rheumatoid arthritis (RA) and may trigger its onset. In this study, researchers performed joint and dental examinations, determined Porphyromonas gingivalis (P. gingivalis) antibodies, and examined inflammatory microenvironments in early and chronic RA patients.

Twenty-three RA patients, (15 new-onset disease, eight chronic) and 20 age/gender-matched healthy subjects (HS) without periodontitis/RA were enrolled in this study. Serum P. gingivalis IgG antibodies were measured by ELISA. Twenty inflammatory mediators were measured in serum, saliva, gingival crevicular fluid (GCF), and joint fluid by Luminex.

The 23 patients (87% female) received routine dental care, except for one; none currently smoked. Of the 23 RA patients, 10 had gingivitis and nine had periodontitis. RA patients exhibited increased pocket depth, clinical attachment loss, bleeding on probing and GCF volume compared with HS. Six of 23 patients had P. gingivalis antibodies, and all six had periodontitis.
RA patients showed a marked inflammatory profile in all microenvironments, including oral, despite routine dental care. P. gingivalis antibodies can be considered as biomarkers for rheumatologists in identifying those who may benefit from periodontal treatment.

Wednesday, March 11, 2015

Graphene: A new tool for fighting cavities and gum disease?


Dental diseases, which are caused by the overgrowth of certain bacteria in the mouth, are among the most common health problems in the world. Now scientists have discovered that a material called graphene oxide is effective at eliminating these bacteria, some of which have developed antibiotic resistance. They report the findings in the journal ACS Applied Materials & Interfaces.

Zisheng Tang and colleagues point out that dentists often prescribe traditional antibiotics to get rid of bacteria that cause tooth decay or gum disease. But with the rise in antibiotic resistance, new approaches are needed to address these problems, which can lead to tooth loss. Previous studies have demonstrated that graphene oxide -- carbon nanosheets studded with oxygen groups -- is a promising material in biomedical applications. It can inhibit the growth of some bacterial strains with minimal harm to mammalian cells. Tang's team wanted to see if the nanosheets would also stop the specific bacteria that cause dental diseases.

In the lab, the researchers tested the material against three different species of bacteria that are linked to tooth decay and gum disease. By destroying the bacterial cell walls and membranes, graphene oxide effectively slowed the growth of the pathogens. The researchers conclude that the nanosheets could have potential uses in dental care.