According to the American Academy of Implant Dentistry (AAID), 15 million Americans have crown or bridge replacements and three million have dental implants -- with this latter number rising by 500,000 a year. The AAID estimates that the value of the American and European market for dental implants will rise to $4.2 billion by 2022.
Dental implants are a successful form of treatment for patients, yet according to a study published in 2005, five to 10 per cent of all dental implants fail.
The reasons for this failure are several-fold - mechanical problems, poor connection to the bones in which they are implanted, infection or rejection. When failure occurs the dental implant must be removed.
The main reason for dental implant failure is peri-implantitis. This is the destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. This occurs when pathogenic microbes in the mouth and oral cavity develop into biofilms, which protects them and encourages growth. Peri-implantitis is caused when the biofilms develop on dental implants.
A research team comprising scientists from the School of Biological Sciences, Peninsula Schools of Medicine and Dentistry and the School of Engineering at the University of Plymouth, have joined forces to develop and evaluate the effectiveness of a new nanocoating for dental implants to reduce the risk of peri-implantitis.
The results of their work are published in the journal Nanotoxicology.
In the study, the research team created a new approach using a combination of silver, titanium oxide and hydroxyapatite nanocoatings.
The application of the combination to the surface of titanium alloy implants successfully inhibited bacterial growth and reduced the formation of bacterial biofilm on the surface of the implants by 97.5 per cent.
Not only did the combination result in the effective eradication of infection, it created a surface with anti-biofilm properties which supported successful integration into surrounding bone and accelerated bone healing.
Professor Christopher Tredwin, Head of Plymouth University Peninsula School of Dentistry, commented: "In this cross-Faculty study we have identified the means to protect dental implants against the most common cause of their failure. The potential of our work for increased patient comfort and satisfaction, and reduced costs, is great and we look forward to translating our findings into clinical practice."
The University of Plymouth was the first university in the UK to secure Research Council Funding in Nanoscience and this project is the latest in a long line of projects investigating nanotechnology and human health.
Nanoscience activity at the University of Plymouth is led by Professor Richard Handy, who has represented the UK on matters relating to the Environmental Safety and Human Health of Nanomaterials at the Organisation for Economic Cooperation and Development (OECD). He commented: "As yet there are no nano-specific guidelines in dental or medical implant legislation and we are, with colleagues elsewhere, guiding the way in this area. The EU recognises that medical devices and implants must: perform as expected for its intended use, and be better than similar items in the market; be safe for the intended use or safer than an existing item, and; be biocompatible or have negligible toxicity."
He added: "Our work has been about proving these criteria which we have done in vitro. The next step would be to demonstrate the effectiveness of our discovery, perhaps with animal models and then human volunteers."
Dr Alexandros Besinis Lecturer in Mechanical Engineering at the School of Engineering, University of Plymouth, led the research team. He commented: "Current strategies to render the surface of dental implants antibacterial with the aim to prevent infection and peri-implantitis development, include application of antimicrobial coatings loaded with antibiotics or chlorhexidine. However, such approaches are usually effective only in the short-term, and the use of chlorhexidine has also been reported to be toxic to human cells. The significance of our new study is that we have successfully applied a dual-layered silver-hydroxyapatite nanocoating to titanium alloy medical implants which helps to overcome these risks."
A team of scientists from The Forsyth Institute and the Dasman Diabetes Institute in Kuwait have found that metabolic diseases, which are characterized by high blood pressure, high blood sugar, and obesity -- leads to changes in oral bacteria and puts people with the disease at a greater risk for poor oral health. This study of more than 8,000 ten year olds in Kuwait showed that metabolic diseases lead to increases in salivary glucose; alterations of the bacteria found in the mouth; and increased risk of cavities and gum disease. This work reinforces the need for preventive dental care and greater integration between medical and dental care.
The study, titled, "The Salivary Microbiome is altered in the Presence of High Salivary Glucose," can be found on PLOS ONE. Over the past ten years, it has become clear that defining a "healthy" microbiome is a critical step for discovering how variations in the bacteria found in and on our body contribute to both disease and wellbeing. While scientists now know a great deal about what bacteria live in our mouth and throughout the body, it is still unclear whether differences in the human microbiome that are seen in many disease states are a symptom of the disease or part of the underlying cause.
"The mouth represents a rich microbiome that is easily accessible," said Dr. Max Goodson, the study's lead author. "Our research is providing further evidence of the connections between the mouth and some of society's most costly and deadly systemic diseases--and of the importance of using the mouth as a tool for preventive health."
Summary of Study
We measured the glucose concentration, bacterial counts, and relative frequencies of 42 bacterial species in whole saliva samples from 8,173 Kuwaiti adolescents (mean age 10.00 ± 0.67 years) using DNA probe analysis. In addition, clinical data related to obesity, dental caries, and gingivitis were collected. Data were compared between adolescents with high salivary glucose (HSG); glucose concentration and those with low salivary glucose. Investigators found that HSG was associated with dental caries and gingivitis in the study population. The overall salivary bacterial load in saliva decreased with increasing salivary glucose concentration. Under HSG conditions, the bacterial count for 35 (83%) of 42 species was significantly reduced, and relative bacterial frequencies in 27 species (64%) were altered, as compared with LSG conditions. These alterations were stronger predictors of high salivary glucose than measures of oral disease, obesity, sleep or fitness. These observations clearly indicate that metabolic diseases, such as diabetes, that produce elevated glucose in blood and saliva can significantly alter the oral microflora.
Samples were obtain through the Forsyth Kuwait Healthy Life Study, is a longitudinal cohort investigation of more than 8,000 children. Forsyth has worked with The Dasman Diabetes Institute and the Kuwait/Forsyth School program to conduct a clinical investigation of the development of obesity, metabolic syndrome and type 2 diabetes in Kuwaiti children. During the five-year study, the body weight, height, blood pressure and fitness were measured, oral disease was evaluated, nutritional information was collected, questionnaires on sleep and medical history were answered and saliva was collected for analysis.
In a study of 1566 community-dwelling Japanese elderly who were followed for 5 years, the risk of developing dementia was elevated in individuals with fewer remaining teeth.
Individuals with 10-19, 1-9, and no teeth had 62%, 81%, and 63% higher risks of dementia, respectively, than individuals with >20 teeth. Likewise, an inverse association was observed between the number of remaining teeth and the risk of developing Alzheimer's disease.
"Our findings emphasize the clinical importance of dental care and treatment, especially in terms of maintenance of teeth from an early age for reducing the future risk of dementia," said Dr. Tomoyuki Ohara, co-author of the Journal of the American Geriatrics Society study.
Adults with gum, or periodontal, disease may be at greater ischemic stroke risk, according to research presented at the American Stroke Association's International Stroke Conference 2017.
Researchers assessed 6,711 adults, who had not had a stroke, for periodontal disease and categorized the adults according to whether they had mild, moderate or severe periodontal disease. They followed patients for 15 years for the incidence of stroke, also documenting the stroke subtype based on cause.
A total of 299 ischemic strokes occurred during the 15 years, including 47 percent that were thrombotic stroke, from a clot within the brain's blood vessels; 26 percent that were cardioembolic, when a blood clot forms in the heart; and 20 percent that were lacunar strokes, which occurs when there is a blockage of small arteries that supply blood to the brain.
Participants with mild periodontal disease were 1.9 times more likely to have an ischemic stroke than those without periodontal disease. Those with moderate periodontal disease had 2.1 times higher ischemic stroke risk and adults with severe gum disease were 2.2 times more likely to suffer an ischemic stroke than those who had no periodontal disease.
The association between increasing levels of periodontal disease and stroke risk was most pronounced in the cardioembolic and thrombotic stroke subtypes.
The graded association between the level of gum disease and incident ischemic stroke, supports a possible causal association between gum disease and ischemic stroke, researchers said.
Estrogen therapy has already been credited with helping women manage an array of menopause-related issues, including reducing hot flashes, improving heart health and bone density, and maintaining levels of sexual satisfaction. Now a new study suggests that the same estrogen therapy used to treat osteoporosis can actually lead to healthier teeth and gums. The study outcomes are being published online today in Menopause, the journal of The North American Menopause Society (NAMS).
As estrogen levels fall during menopause, women become more vulnerable to numerous health issues, including loss of bone mineral density which can lead to osteoporosis. Around the same time, changes in oral health also are common as teeth and gums become more susceptible to disease, which can lead to inflammation, pain, bleeding, and eventually loose or missing teeth.
In the Menopause article "Association between osteoporosis treatment and severe periodontitis in postmenopausal women," 492 postmenopausal Brazilian women aged 50 to 87 years, 113 in osteoporosis treatment and 379 not treated, were evaluated to determine whether osteoporosis treatment could help increase the bone mineral density in their jaws and, subsequently, improve overall oral health.
The study found that the rate of occurrence of severe periodontitis was 44% lower in the postmenopausal osteoporosis-treatment group than in the untreated group. Treatment consisted of systemic estrogen alone or estrogen plus progestin, as well as calcium and vitamin D supplements, for a minimum of six months.
"Osteoporosis can occur throughout the body, including the jaw, and lead to an increased risk of periodontal disease," says Dr. JoAnn Pinkerton, NAMS executive director. "This study demonstrates that estrogen therapy, which has proven to be effective in preventing bone loss, may also prevent the worsening of tooth and gum disease. All women, but especially those with low estrogen or on bisphosphonate treatment for osteoporosis, should make good dental care a part of their healthy lifestyles."
Dentists aren't the only people who influence how we take care of our teeth; our friends and family play a big role, too. That is the conclusion of Brenda Heaton, an assistant professor of health policy and health services research at Boston University's Henry M. Goldman School of Dental Medicine, who is presenting her research on February 19, 2017, at the American Association for the Advancement of Science (AAAS) conference in Boston.
Heaton specializes in social epidemiology with a focus on oral health. In 2008, she, along with other members of BU's Center for Research to Evaluate & Eliminate Dental Disparities, began a new line of research, focused on understanding oral health and disease among residents in Boston public housing. The majority of the work to date has focused on whether or not "motivational interviewing" can influence how women care for their children's diet and oral health--specifically, the impact on kids with dental caries (also known as tooth decay). There is mounting evidence that one-on-one behavioral interventions, like motivational interviewing, may change short-term behavior, but the effects don't last long. "We started to get a sense that there may be more influences that we need to acknowledge beyond just the individual," says Heaton. She found that social networks--not Facebook and Twitter, but networks of friends, family, and acquaintances--may play an overlooked role in oral health care.
Some women Heaton interviewed "had been born and raised in the unit that they were living in, and were now raising their own child in that unit," she says, "so we had grandmother, mother, and child in one unit." Those close connections influenced how people behaved, and to make significant progress against diseases like tooth decay, Heaton had to tap into those networks herself.
That is not easy, but it is important, says Thomas Valente, a professor of preventive medicine at the University of Southern California and an expert in social networks in health care. People believe information more when it comes from someone they know or respect, and evidence suggests that people are more willing to trust people who are like them. All too often, says Valente, who was not involved in this study, health information is handed to a community by people on the outside, and it is less impactful. "It's like West Side Story," says Valente. "It's like being a Shark and having a Jet come up to you and tell you to do something. It is just not going to happen."
Heaton wants to spread resources about good oral health, not only to combat tooth decay but also because oral health is intertwined with other health concerns. "Sugar-sweetened beverage [consumption is] something that we are very interested in, not only because it is a huge risk factor for oral health outcomes, but it is also a huge risk factor for obesity and other obesity-related health conditions," she says.
To understand the connections that already existed within the community, Heaton needed to draw a social map. Since 2008, her team has interviewed close to 200 women living in Boston public housing and identified nearly 1,000 individuals who were influential. Heaton is using those network maps to find similarities about how information flows through these communities.
The ultimate goal, she says, is to use the map to introduce health information and resources into a community in ways that change long-term behaviors.
"You can't design those interventions until you actually have a really strong grasp of the network structure," says Heaton. For instance, if you want to make an impact, should you look for community members with the most personal connections or for people with large influence but fewer personal ties? Should you take advantage of existing connections or seed new ones?
The power of this approach is that it focuses on prevention rather than cures, says Heaton. It might take a village, but tooth decay "is an entirely preventable health outcome."
Why do some people develop caries even though they always brush their teeth carefully while others are less stringent regarding dental hygiene yet do not have any holes? Ultimately, both have bacteria on the surface of their teeth which can attack the enamel. Enamel forms via the mineralization of specific enamel proteins. If the outer layer of the teeth is defective, tooth decay can strike.
Researchers from the University of Zurich have now pinpointed a gene complex for the first time that is responsible for the formation of tooth enamel. Two teams from the Centre of Dental Medicine and the Institute of Molecular Life Sciences used mice with varying mutations of the enamel proteins involved in the so-called Wnt signaling pathway. Thanks to this transmission route, human and animal cells respond to external signals and specifically activate selected genes in the cell nucleus. The signaling pathway is essential for embryonal development and also plays a pivotal role in the development of cancer or physical malformations.
Mutations in proteins trigger defective tooth enamel
"All mice with mutations in these proteins exhibit teeth with enamel defects," explains Pierfrancesco Pagella, one of the study's two first authors. "Therefore, we demonstrated that there is a direct link between mutations in the genetic blueprints for these proteins and the development of tooth enamel defects." This genetic discovery goes a long way towards improving our understanding of the production of tooth enamel.
The team of researchers was the first in the world to use modern genetic, molecular and biochemical methods to study tooth enamel defects in detail. "We discovered that three particular proteins involved in the Wnt signaling pathway aren't just involved in the development of severe illnesses, but also in the qualitative refinement of highly developed tissue," says co-first author Claudio Cantù from the molecular biologist research group lead by Prof. Konrad Basler. "If the signal transmission isn't working properly, the structure of the tooth enamel can change."
Increased risk of caries with defective tooth enamel
The hardness and composition of the tooth enamel can affect the progression of caries. "We revealed that tooth decay isn't just linked to bacteria, but also the tooth's resistance," says Thimios Mitsiadis, Professor of Oral Biology at the Center of Dental Medicine. Bacteria and their toxic products can easily penetrate enamel with a less stable structure, which leads to carious lesions, even if oral hygiene is maintained.
Understanding the molecular-biological connections of tooth enamel development and the impact of mutations that lead to enamel defects opens up new possibilities for the prevention of caries. "New products that hinder the progress of tooth caries in the event of defective tooth enamel will enable us to improve the dental health of patients considerably," adds Mitsiadis.