Premie's And Their Teeth

Our knowledge about premature children, and their physical and mental development as they grow up, is constantly growing. In recent years several studies of children's dental health have been published by researchers at the Faculty of Odontology in Malmö. Liselotte Paulsson-Björnsson, a specialist in orthodontics, has studied 80 children born before week 33 of pregnancy. "We have examined how their teeth are developing and, among other things, we've looked at their bites. We've also checked their need for orthodontic adjustments and found that it is greater than in the control group, children born at full term," she says. The children participating in the various studies were born in the mid 1990s and were examined when they developed their first permanent teeth at the age of eight to ten. The first permanent teeth are the front teeth in the upper and lower jaw and the so-called six-year molars, the first big molars. The results show that the teeth of premature children were up to ten percent smaller compared with the control group. The earlier the children were born the smaller their teeth were. "When we examined the children we also saw that their teeth were farther apart," says Liselotte Paulsson-Björnsson, who stresses that having small teeth as such is not a serious problem, but it can be aesthetically problematic to have large gaps between your teeth. "But these problems can be addressed. We can move teeth if the gaps between them are too large, and there is also good material to extend teeth if they're too small." Disturbances in the teeth's mineralization phase can also lead to spots on the front teeth, but this is also a problem that can be dealt with using cosmetic dental treatments. Liselotte Paulsson-Björnsson is now planning new studies to follow these children into their teens. Among other things, she will be studying whether all permanent teeth are affected in terms of size, or only the ones that are formed in connection with birth. She also wants to study the children's quality of life in relation to their dental status. "But as care of premature children is under constant development, it's not possible to automatically transfer my findings to children being born prematurely now," she says

New Gel Causes The Body To Form Teeth

A bit of pressure from a new shrinking, sponge-like gel is all it takes to turn transplanted unspecialized cells into cells that lay down minerals and begin to form teeth. The bioinspired gel material could one day help repair or replace damaged organs, such as teeth and bone, and possibly other organs as well, scientists from the Wyss Institute for Biologically Inspired Engineering at Harvard University, Harvard School of Engineering and Applied Sciences (SEAS), and Boston Children's Hospital report recently in Advanced Materials. "Tissue engineers have long raised the idea of using synthetic materials to mimic the inductive power of the embryo," said Don Ingber, M.D., Ph.D., Founding Director of the Wyss Institute, Judah Folkman Professor of Vascular Biology at Harvard Medical School, Professor of Bioengineering at SEAS, and senior author of the study. "We're excited about this work because it shows that it really is possible." Embryonic tissues have the power to drive cells and tissues to specialize and form organs. To do that, they employ biomolecules called growth factors to stimulate growth; gene-activating chemicals that cause the cells to specialize, and mechanical forces that modulate cell responses to these other factors. But so far tissue engineers who want to build organs in the laboratory have employed only two of the three strategies - growth factors and gene-activating chemicals. Perhaps as a result, they have not yet succeeded in producing complex three-dimensional tissues. A few years ago, Ingber and Tadanori Mammoto, M.D., Ph.D., Instructor in Surgery at Boston Children's Hospital and Harvard Medical School, investigated a process called mesenchymal condensation that embryos use to begin forming a variety of organs, including teeth, cartilage, bone, muscle, tendon, and kidney. In mesenchymal condensation, two adjacent tissue layers - loosely packed connective-tissue cells called mesenchyme and sheet-like tissue called an epithelium that covers it - exchange biochemical signals. This exchange causes the mesenchymal cells to squeeze themselves tightly into a small knot directly below where the new organ will form. By examining tissues isolated from the jaws of embryonic mice, Mammoto and Ingber showed that when the compressed mesenchymal cells turn on genes that stimulate them to generate whole teeth composed of mineralized tissues, including dentin and enamel. Inspired by this embryonic induction mechanism, Ingber and Basma Hashmi, a Ph.D. candidate at SEAS who is the lead author of the current paper, set out to develop a way to engineer artificial teeth by creating a tissue-friendly material that accomplishes the same goal. Specifically, they wanted a porous sponge-like gel that could be impregnated with mesenchymal cells, then, when implanted into the body, induced to shrink in 3D to physically compact the cells inside it. To develop such a material, Ingber and Hashmi teamed up with researchers led by Joanna Aizenberg, Ph.D., a Wyss Institute Core Faculty member who leads the Institute's Adaptive Materials Technologies platform. Aizenberg is the Amy Smith Berylson Professor of Materials Science at SEAS and Professor of Chemistry and Chemical Biology at Harvard University. They chemically modified a special gel-forming polymer called PNIPAAm that scientists have used to deliver drugs to the body's tissues. PNIPAAm gels have an unusual property: they contract abruptly when they warm. But they do this at a lukewarm temperature, whereas the researchers wanted them to shrink specifically at 37°C - body temperature - so that they'd squeeze their contents as soon as they were injected into the body. Hashmi worked with Lauren Zarzar, Ph.D., a former SEAS graduate student who's now a postdoctoral associate at Massachusetts Institute of Technology, for more than a year, modifying PNIPAAm and testing the resulting materials. Ultimately, they developed a polymer that forms a tissue-friendly gel with two key properties: cells stick to it, and it compresses abruptly when warmed to body temperature. As an initial test, Hashmi implanted mesenchymal cells in the gel and warmed it in the lab. Sure enough, when the temperature reached 37°C, the gel shrank within 15 minutes, causing the cells inside the gel to round up, shrink, and pack tightly together. "The reason that's cool is that the cells are alive," Hashmi said. "Usually when this happens, cells are dead or dying." Not only were they alive - they activated three genes that drive tooth formation. To see if the shrinking gel also worked its magic in the body, Hashmi worked with Mammoto to load mesenchymal cells into the gel, then implant the gel beneath the mouse kidney capsule - a tissue that is well supplied with blood and often used for transplantation experiments. The implanted cells not only expressed tooth-development genes - they laid down calcium and minerals, just as mesenchymal cells do in the body as they begin to form teeth. "They were in full-throttle tooth-development mode," Hashmi said. In the embryo, mesenchymal cells can't build teeth alone - they need to be combined with cells that form the epithelium. In the future, the scientists plan to test whether the shrinking gel can stimulate both tissues to generate an entire functional tooth.

"Big Tooth" Is Watching You !

Researchers at the National University of Taiwan have developed a “smart” tooth device that monitors an individual ‘s oral habits by recording movement of the jaw and generating data that is fed to a computer via the tooth’s sensor , then paired with an oral action . The device can be used as a detachable fake tooth or inserted in a crown , allowing doctors to track chewing , drinking , eating , coughing and even smoking – and (hopefully) allow them help treating a wide range of problems . In testing the device , the researchers asked 8 volunteers to perform 30 – second tasks such as chewing gum , reading aloud , drinking a bottle of water and coughing . The device was able to determine what action each volunteer performed with 94% accuracy . Because the mouth is “an opening into human health” , the researchers contend the device has the potential to enhance existing healthcare monitoring applications such as dietary tracking.

New Study About Heart Surgery And Infected Teeth

Abscessed or infected teeth are often removed before heart surgery, as this decreases the risk of infection during surgery and decreases the risk of an inflammation of the inner layer of the heart - called endocarditis - following surgery. But although it is standard practice to remove bad teeth prior to heart surgery, there is only limited evidence that supports this practice. The new study set out to evaluate what harms may be associated with dental extraction before cardiovascular surgery. "Guidelines from the American College of Cardiology and American Heart Association label dental extraction as a minor procedure, with the risk of death or non-fatal heart attack estimated to be less than 1%," says study author and anesthesiologist Dr. Mark M. Smith, from the Mayo Clinic in Rochester, MN. "Our results, however, documented a higher rate of major adverse outcomes, suggesting physicians should evaluate individualized risk of anesthesia and surgery in this patient population," he adds. Heart attack, stroke, kidney failure and death Dr. Smith and his colleagues found that 8% of patients who had teeth removed prior to heart surgery experienced adverse outcomes. These included heart attack, stroke, kidney failure and death. Overall, 3% of patients died after dental extraction and before the heart surgery could take place. But this study did have some limitations. Co-author and cardiac surgeon Dr. Joseph A. Dearani says: "With the information from our study we cannot make a definitive recommendation for or against dental extraction prior to cardiac surgery. We recommend an individualized analysis of the expected benefit of dental extraction prior to surgery weighed against the risk of morbidity and mortality as observed in our study." Established thinking on dental surgery and cardiac surgery is changing The results of the Mayo Clinic study contribute to an ongoing departure in current thinking on the relationship between dental surgery and cardiac surgery. "'Accepted wisdom' leads surgeons to request dental reviews prior to cardiac surgery in many thousands of patients annually around the world," says Dr. Michael Jonathan Unsworth-White, from Derriford Hospital in Plymouth, UK. "Dr. Smith's group asks us to question this philosophy. It is a significant departure from current thinking." Writing in a linked comment, Dr. Unsworth-White draws parallels with another recent change of consensus. In patients undergoing dental work who have existing heart problems, it has previously been standard practice to prescribe prophylactic antibiotics. Again, this was because there is a known link between dental bacteremia and endocarditis. But more recent studies have suggested that the potential side effects of these antibiotics may outweigh the benefits. Dr. Unsworth-White explains: "The American Heart Association and the National Institute for Health and Clinical Excellence in the UK have withdrawn support for this practice of prophylactic antibiotics because the danger from overuse of antibiotics outweighs any other potential risks. Regular tooth brushing, flossing, and even chewing gum are now recognized to dislodge as much, if not more, bacteremia than most dental procedures."