New Way To Make Teeth

Alligators may help scientists learn how to stimulate tooth regeneration in people, according to new research led by the Keck School of Medicine of USC. For the first time, a global team of researchers led by USC pathology Professor Cheng-Ming Chuong, M.D., Ph.D., has uncovered unique cellular and molecular mechanisms behind tooth renewal in American alligators. Their study, titled "Specialized stem cell niche enables repetitive renewal of alligator teeth," appears in Proceedings of the National Academy of Sciences, the official journal of the United States National Academy of Sciences. "Humans naturally only have two sets of teeth - baby teeth and adult teeth," said Chuong. "Ultimately, we want to identify stem cells that can be used as a resource to stimulate tooth renewal in adult humans who have lost teeth. But, to do that, we must first understand how they renew in other animals and why they stop in people." Whereas most vertebrates can replace teeth throughout their lives, human teeth are naturally replaced only once, despite the lingering presence of a band of epithelial tissue called the dental lamina, which is crucial to tooth development. Because alligators have well-organized teeth with similar form and structure as mammalian teeth and are capable of lifelong tooth renewal, the authors reasoned that they might serve as models for mammalian tooth replacement. "Alligator teeth are implanted in sockets of the dental bone, like human teeth," said Ping Wu, Ph.D., assistant professor of pathology at the Keck School of Medicine and first author of the study. "They have 80 teeth, each of which can be replaced up to 50 times over their lifetime, making them the ideal model for comparison to human teeth." Using microscopic imaging techniques, the researchers found that each alligator tooth is a complex unit of three components - a functional tooth, a replacement tooth, and the dental lamina - in different developmental stages. The tooth units are structured to enable a smooth transition from dislodgement of the functional, mature tooth to replacement with the new tooth. Identifying three developmental phases for each tooth unit, the researchers conclude that the alligator dental laminae contain what appear to be stem cells from which new replacement teeth develop. "Stem cells divide more slowly than other cells," said co-author Randall B. Widelitz, Ph.D., associate professor of pathology at the Keck School of Medicine. "The cells in the alligator's dental lamina behaved like we would expect stem cells to behave. In the future, we hope to isolate those cells from the dental lamina to see whether we can use them to regenerate teeth in the lab." The researchers also intend to learn what molecular networks are involved in repetitive renewal and hope to apply the principles to regenerative medicine in the future. The authors also report novel cellular mechanisms by which the tooth unit develops in the embryo and molecular signaling that speeds growth of replacement teeth when functional teeth are lost prematurely.

Prevent Cavities With Oil

Coconut oil, a natural antibiotic when digested, destroys the bacteria that cause tooth decay, researchers at the Athlone Institute of Technology, Ireland, reported at the Society for General Microbiology's autumn conference at the University of Warwick, England, today. They added that the antibiotic component in digested coconut oil could be added to dental care products. Dr Damien Brady and team set out to determine whether coconut oil might have antibacterial qualities at combating some strains of Streptococcus bacteria which commonly inhabit the human mouth and cause tooth decay. They tested the coconut oil in its natural and semi-digested state. They added enzymes so that the oil could be tested in a digested state. Although natural, undigested coconut oil appeared to have no impact, the scientists found that the digested oil stopped most Streptococcus bacteria from multiplying. Of particular interest was Streptococcus mutans, a type of bacterium which produces teeth-decaying acids. Dr. Brady explained that previous studies had demonstrated that certain foodstuffs, when semi-digested, had the capacity to destroy micro-organisms. The binding of S. mutans to tooth enamel was significantly reduced when teeth were exposed to enzyme-modified milk, one study had shown. That study encouraged this team to test out other foods. The researchers plan to see how coconut oil interacts with Streptococcus bacteria at molecular level. They also want to find out whether digested coconut oil might combat other pathogens, including some types of bacteria and yeasts. The team inform that preliminary studies have found that semi-digested coconut oil destroys Candida albicans, a yeast that causes thrush. The scientists believe that enzyme-modified coconut oil, meaning in its semi-digested state, may have commercially viable antimicrobial qualities for the oral healthcare industry. Dr Brady said: "Dental caries is a commonly overlooked health problem affecting 60-90% of children and the majority of adults in industrialized countries. Incorporating enzyme-modified coconut oil into dental hygiene products would be an attractive alternative to chemical additives, particularly as it works at relatively low concentrations. Also, with increasing antibiotic resistance, it is important that we turn our attention to new ways to combat microbial infection. Our data suggests that products of human digestion show antimicrobial activity. This could have implications for how bacteria colonize the cells lining the digestive tract and for overall gut health. Our research has shown that digested milk protein not only reduced the adherence of harmful bacteria to human intestinal cells but also prevented some of them from gaining entrance into the cell. We are currently researching coconut oil and other enzyme-modified foodstuffs to identify how they interfere with the way bacteria cause illness and disease." Streptococcus mutans (S. mutans) Streptococcus mutans (S. mutans) is an anaerobic, Gram-positive, coccus shaped bacterium. Coccus shaped means the bacterium has a spherical or spheroidal shape. S. mutans commonly inhabits the human oral cavity and is the leading cause of tooth decay globally. S. mutans, according to experts, is the most cariogenic of all the oral streptococci. Cariogenic means producing or promoting the development of tooth decay. The bacterium sticks to the surface of the tooth and exists on certain types of carbohydrates. As it metabolizes sugars and other sources of energy, it produces an acid that damages teeth. Virtually all humans carry S. mutans in their oral cavity.

Colds and Your Toothbrush

Word on the street has it you should replace your toothbrush after suffering from a cold, the flu or a bout of strep throat. That may not be necessary - at least when it comes to sore throats, according to a study presented at the Pediatric Academic Societies (PAS) annual meeting in Washington, DC. Some health care professionals advise children to toss their toothbrushes if they have been diagnosed with strep throat. Researchers from University of Texas Medical Branch (UTMB) at Galveston wanted to determine if that advice is warranted. First, they tried to grow group A Streptococcus (GAS), the bacteria that causes strep throat, on toothbrushes that had been exposed to the bacteria in a laboratory. The bacteria did in fact grow and remained on the toothbrushes for at least 48 hours. Surprisingly, two new toothbrushes that were not exposed to GAS and served as controls also grew bacteria even though they had been removed from their packaging in a sterile fashion. An adult-size toothbrush grew gram-negative bacilli, and a child-size toothbrush grew gram-positive cocci, which was identified as Staphylococcus. Since this was not the main focus of the study, the researchers did not investigate this finding further. Next, they investigated whether GAS would grow on toothbrushes used by children who had strep throat. Fourteen patients who were diagnosed with strep throat, 13 patients with sore throats without strep and 27 well patients ages 2 to 20 years were instructed to brush their teeth for one minute with a new toothbrush. Afterwards, the toothbrushes were placed in a sterile cover and taken to a lab where they were tested for GAS bacteria growth. GAS was recovered from only one toothbrush, which had been used by a patient without strep throat. The other study toothbrushes failed to grow GAS but did grow other bacteria that are common in the mouth. "This study supports that it is probably unnecessary to throw away your toothbrush after a diagnosis of strep throat," said co-author Judith L. Rowen, MD, associate professor of pediatrics in the Department of Pediatrics at UTMB. Study co-author Lauren K. Shepard, DO, a resident physician in the Department of Pediatrics at UTMB, noted that the study was small. Larger studies with more subjects need to be conducted to confirm that group A Streptococcus does not grow on toothbrushes used at home by children with strep throat, she said .

The Power Of Fluoride

In an advance toward solving a 50-year-old mystery, scientists are reporting new evidence on how the fluoride in drinking water, toothpastes, mouth rinses and other oral-care products prevents tooth decay. Their report appears in the ACS journal Langumir. Karin Jacobs and colleagues explain that despite a half-century of scientific research, controversy still exists over exactly how fluoride compounds reduce the risk of tooth decay. That research established long ago that fluoride helps to harden the enamel coating that protects teeth from the acid produced by decay-causing bacteria. Newer studies already found that fluoride penetrates into and hardens a much thinner layer of enamel than previously believed, lending credence to other theories about how fluoride works. The report describes new evidence that fluoride also works by impacting the adhesion force of bacteria that stick to the teeth and produce the acid that causes cavities. The experiments - performed on artificial teeth (hydroxyapatite pellets) to enable high-precision analysis techniques - revealed that fluoride reduces the ability of decay-causing bacteria to stick, so that also on teeth, it is easier to wash away the bacteria by saliva, brushing and other activity.

Rinsing Your Mouth Can Help Your Arteries

Cleaning your mouth and cleaning your arteries could be as simple as a once-a-day oral rinse if additional studies confirm preliminary findings about a new product. Biomedical Development Corporation (BDC) on April 23 will present data to the American Academy of Oral Medicine showing that its oral rinse was safe and effective at fighting gingivitis in a recent clinical trial. But the most surprising finding of the study was that users of the oral rinse showed lower LDL cholesterol levels than the placebo group. "We didn't expect to see any difference in LDL cholesterol," said Dr. Charles Gauntt, the study's principal investigator. "We expected to see improvements in oral health, and we did. But we also monitored a number of biological markers for inflammation. The results showed the oral rinse had no adverse effects and users exhibited lower levels of LDL, or what many people know as bad cholesterol. This definitely merits further study." The three-month, phase II trial was funded by the National Heart, Lung and Blood Institute (NHLBI). The trial was preceded by a phase I clinical trial for safety and a phase II pilot efficacy clinical trial. Another, longer phase II trial is now under way and will evaluate gingivitis patients over a six-month period. This new trial, conducted by the Center for Oral Health Research at the University of Kentucky, will monitor gingivitis and LDL cholesterol levels as the previous trial did. The NHLBI is funding the research, which is also supported by the Kentucky SBIR/STTR Matching Funds Program. BDC's product is designed as a once-daily, 30-second oral rinse. The active ingredient is a proprietary formula based on iodine. The National Institutes of Health Office of Dietary Supplements fact sheet on iodine addresses a variety of important roles for iodine in the human body, from helping the thyroid function properly to appearing to play a part in the body's immune response system. About 40 percent of the world's population is thought to be at risk of iodine deficiency. Gauntt also notes that iodine is known to be effective in inactivating viruses, bacteria and funguses. He is intrigued by recent clinical studies showing what appears to be a closer link between oral health and cardiovascular health. Although scientists cannot yet fully explain how the two are connected, there is ample statistical evidence to suggest that gum disease and heart disease are closely related. According to the American Academy of Periodontology, people with periodontal disease (gum disease) are almost twice as likely to have coronary artery disease. The academy also notes that one study showed stroke victims were more likely than the general population to also have oral infections. Gauntt believes that future research might make it much clearer that a healthy mouth, free of gum disease and its associated toxins and bacteria, is critical to a healthy cardiovascular system. Although further study is required, he adds, he believes BDC's oral rinse may eventually prove to be an important tool in keeping both mouths and cardiovascular systems healthy, in addition to proper nutrition and exercise. Phyllis Siegel, CEO of BDC, said that while results of its ongoing clinical trials are pending, a specific formulation of the product called iCLEAN®, designed for general mouth cleaning, will soon be available.

Earliest Dentisty Found !

Team leaders Federico Bernardini and Claudio Tuniz, of the Abdus Salam International Centre for Theoretical Physics in Italy, worked with researchers at Sincrotrone Trieste and other centers in Italy and Australia to analyze the 6,500-year-old "human mandible". The tooth is part of a human jawbone found in Slovenia near Trieste. The researchers note that evidence of prehistoric dentistry is sparse, so they hope the find will help them better understand early dental practices. The tooth is a left canine, whose crown bears the traces of filling with beeswax. The researchers used a range of tools to examine the tooth, including "synchrotron radiation computed micro-tomography (micro-CT), Accelerator Mass Spectrometry (AMS) radiocarbon dating, Infrared (IR) Spectroscopy and Scanning Electron Microscopy (SEM)". The results showed the tooth was worn, exposing an area of dentin, and also bore a vertical crack in the enamel and dentin layers, the upper part of which was filled with beeswax. The team suggests the filling was probably applied around the time of the individual's death, but can't be sure whether it was shortly before or even shortly after. "If the filling was done when the person was still alive, the intervention was likely aimed to relieve tooth sensitivity derived from either exposed dentine and/or the pain resulting from chewing on a cracked tooth," they write. If it was applied before death, then it is the earliest known direct evidence of a dental filling being applied for therapeutic, pain-relieving reasons. In a press statement, Tuniz speculates that the severe wear of the tooth is probably due to the fact people of that era used their teeth for lots of other things, not just eating, for instance Neolithic women used their teeth to cut or hold thread when weaving. Bernardini says this is possibly the "most ancient evidence of pre-historic dentistry in Europe and the earliest known direct example of therapeutic-palliative dental filling so far".