all Harvard School of Dental Medicine stories

Predicting risk of stroke from one’s genetic blueprint

50443248 — Wed, 25 Feb 2009 17:22:04 -0500

A new statistical model could be used to predict an individual’s lifetime risk of stroke, according to the results of a study by Harvard researchers at the Children’s Hospital Boston Informatics Program (CHIP).

NIH awards Harvard Medical School $117.5 million, five-year grant for patient-centered research

404132862 — Thu, 29 May 2008 12:42:32 -0400

The National Institutes of Health today announced that Harvard Medical School (HMS) will receive $117.5 million over the next five years for the establishment of a Clinical and Translational Science Center (CTSC) that will transform patient-oriented, laboratory-to-bedside research at HMS and its affiliated hospitals.

Treasures of Dental School’s old museum opened wide at exhibit

50443248 — Tue, 02 Oct 2007 13:21:28 -0400

The Harvard Dental Museum once held 14,000 specimens, everything from Ralph Waldo Emerson’s dentures to a prehistoric mastodon’s tusk measuring 11 feet in length and weighing 300 pounds.

Emerson’s dentures, which were manufactured around 1870 and are made of porcelain and set in vulcanized rubber, are still extant. But the mastodon’s tusk is nowhere to be found. Only an article from a 1929 issue of the Boston Globe remains, describing how the 50,000-year-old tusk was found near the Arctic Circle and transported by dogsled and boat to Boston.

Marine biology mystery solved

50443248 — Thu, 19 Jul 2007 14:55:11 -0400

Harvard School of Dental Medicine (HSDM) researcher Martin Nweeia has just answered a marine science question that had eluded the scientific community for hundreds of years: why does the narwhal, or "unicorn," whale have an 8-foot-long tooth emerging from its head, and what is its function? Nweeia, a clinical instructor in restorative dentistry and biomaterials sciences at HSDM, will be presenting his conclusions at the 16th Biennial Conference on the Biology of Marine Mammals in San Diego.

Marine biology mystery solved

70652986 — Mon, 26 Mar 2007 05:42:57 -0400

The narwhal has a tooth, or tusk, which emerges from the left side of the upper jaw and is an evolutionary mystery that defies many of the known principles of mammalian teeth. The tooth's unique spiral, the degree of its asymmetry to the left side, and its odd distribution among most males and some females are all unique expressions of teeth in mammals. The narwhal is usually 13 to 15 feet in length and weighs between 2,200 and 3,500 pounds. Its natural habitat is the Atlantic portion of the Arctic Ocean, concentrating in the Canadian High Arctic: Baffin Bay, Davis Strait, and northern Hudson Bay. It is also found in less numbers in the Greenland Sea, extending to Svalbard to Severnaya Zemlya off the coast of Russia.

Harvard School of Dental Medicine researcher Martin Nweeia has discovered that the narwhal's tooth has hydrodynamic sensor capabilities. Ten million tiny nerve connections tunnel their way from the central nerve of the narwhal tusk to its outer surface. Though seemingly rigid and hard, the tusk is like a membrane with an extremely sensitive surface, capable of detecting changes in water temperature, pressure, and particle gradients. Because these whales can detect particle gradients in water, they are capable of discerning the salinity of the water, which could help them survive in their Arctic ice environment. It also allows the whales to detect water particles characteristic of the fish that constitute their diet. There is no comparison in nature and certainly none more unique in tooth form, expression, and functional adaptation.

"Why would a tusk break the rules of normal development by expressing millions of sensory pathways that connect its nervous system to the frigid arctic environment?" says Nweeia. "Such a finding is startling and indeed surprised all of us who discovered it." Nweeia collaborated on this project with Frederick Eichmiller, director of the Paffenbarger Research Center at the National Institute of Standards and Technology, and James Mead, curator of marine mammals at the National Museum of Natural History of the Smithsonian Institution.

Nweeia studied the whales during four trips to the Canadian High Arctic. In the past, many theories have been presented to explain the tooth's purpose and function, none of which have been accepted as definitive. One of the most common is that the tooth is used to display aggression between males, who joust with each other for social hierarchy. Another is that the tooth is a secondary sexual characteristic, like a peacock's feathers or a lion's mane.

Nweeia's findings point to a new direction of scientific investigation. Fewer than 250 papers have been published about the narwhal, and many offer conflicting results. Because of its Arctic habitat and protected status in Canada, the whale is difficult to study. Nweeia has brought together leaders from the fields of marine mammal science, dental medicine, engineering, mathematics, evolutionary biology, anatomy, and histology.

The sensory connections discovered by Nweeia and his colleagues also are capable of tactile ability. Narwhals are known for their "tusking" behavior, when males rub tusks. Because of the tactile sensory ability of the tusk surface, the whales are likely experiencing a unique sensation.

Results from the team's research already has practical applications; studies about the physical makeup of the tusk, which is both strong and flexible, provide insight into ways of improving restorative dental materials. (An 8-foot-long tooth can yield one foot in any direction without breaking). Nweeia also leads the Narwhal Tooth Expeditions and Research Investigation, founded in 2000, which combines scientific experts with Inuit elders, who have collected notes for hundreds of years, to discover the purpose and function of the narwhal tusk.

Nweeia, a clinical instructor in restorative dentistry and biomaterials sciences at HSDM, presented his conclusions Dec. 13, 2005 at the 16th Biennial Conference on the Biology of Marine Mammals in San Diego.

This work was funded by Harvard School of Dental Medicine, the National Geographic Society, Sunstar Butler, the Smithsonian Institution Center for Arctic Studies, Astro-Med Inc., and Fisheries and Oceans, Canada.

Brain chemical serotonin involved in early embryo patterning

70652986 — Mon, 26 Mar 2007 06:18:11 -0400

A study published in the May 10, 2005, Current Biology has ramifications for neuroscience, developmental genetics, evolutionary biology and, possibly, human teratology (a branch of pathology and embryology concerned with abnormal development and congenital malformations). Among other results, the study, which was carried on frog and chick embryos: • Provides the first molecular support for the idea that serotonin is utilized as a large-scale left-right patterning mechanism, thus offering new insight into the basis of position of the heart and other asymmetric, visceral organs. • Identifies a possible novel serotonin signaling pathway, providing evidence that serotonin can signal inside the cell. If also found in mammals, such signaling, which may be important in brain functioning, would suggest numerous new roles and possible targets for serotonin-related drugs like the selective serotonin reuptake inhibitors (SSRI antidepressants such as Prozac and Zoloft) or the monoamine oxidase inhibitors (MAOIs). • Could lead to a greater understanding of potential health risks from drug families that target the serotonin pathway in human patients. • Sheds light on the evolutionary origin of a crucial neurological control system, suggesting that neuronal synapses using serotonin as a neurotransmitter may have arisen through the adaptation of ancient, fundamental cell-cell signals to a new purpose as nervous systems evolved. The team was led by principal investigator Michael Levin, assistant professor at Harvard Medical School. The study was funded by the National Science Foundation and the American Heart Association.

Blue light suppresses oral pathogens

50443248 — Wed, 25 Jul 2007 09:42:32 -0400

Scientists at the Forsyth Institute have found that blue light can be used to selectively suppress certain bacteria commonly associated with destructive gum disease.

The research, published in the April Journal of Antimicrobial Agents and Chemotherapy, suggests that light in the blue region of the visible spectrum might be useful in preventing, controlling, or treating periodontitis - an oral infection that can lead to loss of bone and teeth.

Key to dental enamel formation found

50443248 — Wed, 25 Jul 2007 14:59:57 -0400

Scientists at Harvard-affiliated Forsyth Institute have found and replicated a key aspect of the mechanism by which dental enamel is formed.
The findings, published in the Feb. 14 Journal of Structural Biology, may lead, one day, to new, biological methods for repairing teeth and other mineralized tissues as well as to new, very hard ceramic materials.

Lead author Elia Beniash, staff scientist at Forsyth, explains that enamel, the hardest tissue in the human body, is composed mainly of calcium phosphate mineral crystals. "It is well known that enamel's strength and durability derive from the unique way in which those crystals are organized into parallel bundles called 'rods.'

"In the current research, carried out in test tubes, we demonstrated that the protein amelogenin plays a key role in regulating the organization and growth of these crystals and how it works. We also determined that newly forming enamel structure emerges as a result of cooperative interactions between forming crystals and assembling proteins, rather than sequentially, as in the formation of other mineralized tissues such as bone and dentin [the bony material found under enamel, in teeth]." The scientists worked with mouse amelogenin, which is very similar to the form of the protein found in human teeth.

Henry Margolis, chair of the Forsyth Department of Biomineralization and a co-author of the article, said, "The current findings are a crucial step toward understanding the process of enamel formation. We hope this work will one day lead to an ability to repair damaged tooth enamel."

Another long-term goal is the development of biomimetic, nanostructured materials with properties similar to those of dental enamel. Biomimetic materials or devices are those whose design, organization, and functional properties are modeled on biological systems. Nanostructured materials are those in which the organization is regulated at the submicron level during fabrication. "Such advances will rely on future collaborative studies involving chemists, biophysicists, biologists, and materials scientists," Margolis said.

In addition to his Forsyth appointment, Margolis is associate professor in the Department of Oral and Developmental Biology at the Harvard School of Dental Medicine. The team also included James P. Simmer, associate professor of biologic and materials sciences in the Division of Prosthodontics at the University of Michigan. The research was funded by a grant from the National Institute of Dental and Craniofacial Research and through support provided by The Forsyth Institute.

Scorpion venom blocks bone loss

70652986 — Mon, 26 Mar 2007 05:33:30 -0400

Rats given kalitoxin, from scorpion venom, enjoyed 84 percent less jawbone loss than those that didn't get the injections. "We are very excited because this is the first demonstration that this type of compound may be useful in treating periodontal disease," says Martin Taubman, Harvard professor of oral and developmental biology who chairs the Department of Immunology at the Forsyth Institute. "We hope that our findings will lead to success in alleviating the bone-ravaging effects of many other diseases." Good candidates include rheumatoid arthritis and osteoarthritis. According to researcher Paloma Valverde, who had the original idea for the experiment, kalitoxin blocks Kv1.3, a protein that plays a major role in inflammation. When Kv1.3 is blocked, it decreases the activity of another protein that plays a key role in stimulating bone-eating cells known as osteoclasts. "This is the first study we know of to show that such a blocker can decrease alveolar (jaw) bone loss," Valverde notes. "Furthermore, we observed no toxic side effects. Therefore, we now have a novel and apparently safe strategy to ameliorate bone destruction associated with periodontal disease." Before experiments with humans begin, however, there will need to be toxicology tests. The rats came out fine, but the venom ingredient must be tested for safety in people.

Is your heart in the right place?

70652986 — Mon, 26 Mar 2007 05:32:57 -0400

In a frog, the position of the heart is determined within the first hour in the womb, Harvard scientists have discovered. Researchers all over the world believe that frogs and humans develop in a similar way. Experiments show, for example, that some of the same mechanisms put the hearts of both creatures on the left side. The proteins responsible for shifting around a frog embryo's heart, gut, gall bladder, and other organs are also found in abundance in human embryos. "Our research shows the same protein family, known as 14-3-3, plays important roles across the three kingdoms of living things, fungi, plants, and animals," says Michael Levin, a biologist at the Harvard School of Dental Medicine and the Forsyth Institute in Boston. "Our latest findings provide strong evidence that the determination of right-left asymmetry in vertebrates, possibly including humans, occurs at a much earlier time than previously believed." Levin and two colleagues from the Netherlands described their newest experiments in the Oct. 20, 2003 issue of the journal Development.

Regrowing missing teeth may someday be possibility

70652986 — Mon, 26 Mar 2007 05:25:51 -0400

Regrowing missing teeth may someday be a possibility, based on work by a team of scientists at the Forsyth Institute, an independent, Harvard-affiliated research organization specializing in oral and craniofacial biology. Pamela Yelick, an assistant staff member at the Forsyth Institute and an instructor in oral and developmental biology at the Harvard School of Dental Medicine, says that the research she and her colleagues have carried out should result in a clinical product in about 15 years. "Or maybe sooner. That's probably a pretty conservative estimate," Yelick said. The successful tissue engineering experiment was reported in an article by Yelick and her colleagues in the Oct. 1, 2002, issue of the Journal of Dental Research.

How your heart got where it is

70652986 — Mon, 26 Mar 2007 05:24:06 -0400

A team of scientists at the Harvard School of Dental Medicine and The Forsyth Institute in Boston believes it has found the answer to how bodily organs are formed. And it's electrifying. "All living things generate all sorts of electric fields inside themselves," explains Michael Levin, an assistant professor at the Dental School and a researcher at The Forsyth Institute. "That's part of life. We have discovered a whole new role for these fields, not expected or explored before. We've found that they control the geometric arrangement, the shape, of visceral organs such as the heart, stomach, liver, spleen, and probably the brain." The researchers have also identified the genes that hold the blueprints of this organ geometry.

Mammalian teeth regrown in lab

70652986 — Mon, 26 Mar 2007 05:24:27 -0400

A study involved seeding cells from the immature teeth of six-month old pigs onto biodegradable polymer scaffolds. The researchers then placed these structures into rat hosts. Within 30 weeks, small, recognizable tooth crowns had formed. These contained dentin; odontoblasts, cells that secrete dentin-forming protein; a well-defined pulp chamber; Hertwig's root sheath epithelia; cementoblasts, which form a mineralized tissue that covers the roots; and a morphologically correct enamel organ. The results, demonstrated in some two dozen experiments, represent the first successful generation of mature tooth crowns containing both dentin and enamel. They also suggest that it may be possible to grow teeth of a particular size and shape, according to principal investigator Pamela Yelick, Harvard School of Dental Medicine instructor in oral and developmental biology at the Forsyth Institute and an assistant member of the Forsyth staff. The research was reported in the Oct. 1, 2002, Journal of Dental Research.

Discovering what lives in your mouth

70652986 — Mon, 26 Mar 2007 05:23:35 -0400

Your mouth is a great place for micropests to dwell. Glistening white plateaus, dark crevices, and slimy surfaces boast steamy temperatures of 95 degrees Fahrenheit. The microbes bathe in a saliva-induced humidity of 100 percent, and eat a lavish diet of sugar and other carbohydrates. It's so lush and varied, researcher Donna Mager refers to it as a mini-jungle. Mager is a fellow in oral medicine at the Forsyth Institute, an independent research institution in Boston. Forsyth scientists, most of whom are on the faculty of the Harvard School of Dental Medicine, have found 615 different species of bacteria - and they're still counting.

Will vaccine defense help polish off tooth decay?

70652986 — Mon, 26 Mar 2007 05:14:47 -0400

The key to preventing cavities in teeth lies in controlling an acid-secreting bacterium known as Streptococcus mutans that lives in the mouth. Researchers at the Harvard School of Dental Medicine believe they can prevent cavities for life by vaccinating babies against S. mutans. "If we can get the babies immunized before the bacteria have had a chance to colonize, then we can offer protection for perhaps the rest of their lives," said Daniel Smith, HSDM associate clinical professor of oral biology and pathophysiology. Smith and Martin Taubman, professor of oral biology at HSDM, have worked to develop a vaccine that is effective and easily administered.