Amalgam Fillings Don’t Affect Children’s Brain Development

Dental amalgam tooth fillings do not adversely affect children’s brain development and neurological status, researchers report in the February issue of The Journal of the American Dental Association.

The authors of the report-members of a joint team from the University of Lisbon, Portugal, and the University of Washington, Seattle-studied the possible neurological effects of dental amalgam tooth restorations. Dental amalgam contains elemental mercury combined with other metals such as silver, copper, tin and zinc to form a safe, stable alloy. Dental amalgam has been used for generations to fill decayed teeth that might otherwise have been lost.

Beginning in 1997 and continuing for seven years, the authors studied 507 Portuguese children aged 8 through 12 years who received either amalgam or resin-based composite fillings. They conducted routine clinical neurological examinations to assess two types of neurological signs: hard (indicating damage to specific neural structures) and soft (subtle signs of central nervous system dysfunction that likely point to immature sensory-motor skills rather than to any structural damage in the brain). The researchers also evaluated the children for presence of tremor.

After seven years, the two groups of children did not differ in terms of the presence or absence of hard signs or tremor. They also didn’t differ in terms of the presence or absence or severity of soft signs at any point. Also, as expected in healthy children, the severity of any neurological soft signs diminished as the children aged.

“Even at the levels of amalgam exposure in this study (a mean of 7.7-10.7 amalgam surfaces per subject across the seven years of follow-up),” the authors write, “[we] conclude that exposure to mercury from dental amalgam does not adversely affect neurological status.

“These data indicate the absence of a generalized negative effect on children’s nervous system functions stemming from the presence of dental amalgam,” they continue, “and while we cannot rule out potential adverse reactions in individual children, we found no indications of any.”

Source: Newswise

One Response to “Amalgam Fillings Don’t Affect Children’s Brain Development”

Researchers Use A Patient’s Own Bone To Accelerate Orthodontics

Newswise – Researchers at the University of Southern California School of Dentistry say they have improved upon a surgical procedure developed by periodontist Tom Wilcko that rapidly straightens teeth, delivering a healthy bite and attractive smile in months instead of years.

Led by Hessam Nowzari DDS, PhD, Director of the USC School of Dentistry and Advanced Education in Periodontology program, the researchers have published the first case study of the successful use of a patient’s own bone material for the grafting necessary in the accelerated orthodontic surgical procedure. The report appears in the May 2008 issue of the Compendium of Continuing Education in Dentistry.

Accelerated orthodontics is gaining popularity as a way for patients, particularly adults with mature bones, to speed up the time it takes to straighten misaligned bites and fix crowded teeth. Wilcko, who operates a practice in Erie, Penn., offers courses in the procedure, trademarked as “Wilckodontics.”

USC dentists used a procedure known as PAOO, short for Periodontally Accelerated Osteogenic Orthodontics. With this technique, a periodontist or oral surgeon uses special instruments to score the bone that holds the teeth in place and then applies bone graft material over the grooves. The procedure is done under local anesthetic in the dental office operatory.

As the bone begins to heal, it softens slightly, allowing teeth to be moved into alignment with dental braces in a matter of months, rather than the years required with traditional orthodontics. The cost for accelerated orthodontics typically ranges from $10,000 to $15,000, depending on the course of treatment.

Prior to the USC study, the bone graft material used for this procedure was bovine bone and bioactive glass particles to help the bone strengthen as it healed.

Nowzari says that his team believed they could improve the technique by using the patient’s own bone instead of the artificial or bovine graft.

“Given a choice for grafts, nothing is better than a patient’s own tissue,” Nowzari explains. “It encourages new, healthy bone formation in the grafted area. It’s very safe and eliminates the risk of any disease transmission.”

Contact Information
Angelica Urquijo (213) 740-6568 office (213) 271-4189 cell

Scientists Discover How Maternal Smoking

Can Cause Cleft Lip and Palate

Scientists supported by the National Institute of Dental and Craniofacial Research (NIDCR), part of the National Institutes of Health, report that women who smoke during pregnancy and carry a fetus whose DNA lacks both copies of a gene involved in detoxifying cigarette smoke substantially increase their baby’s chances of being born with a cleft lip and/or palate.

According to the scientists, about a quarter of babies of European ancestry and possibly up to 60 percent of those of Asian ancestry lack both copies of the gene called GSTT1. Based on their data, published in the January issue of the American Journal of Human Genetics, the scientists calculated that if a pregnant woman smokes 15 cigarettes or more per day, the chances of her GSTT1-lacking fetus developing a cleft increase nearly 20 fold. Globally, about 12 million women each year smoke through their pregnancies.

Dr. Jeff Murray, a scientist at the University of Iowa and senior author of the study, noted that parents who are considering having a child and need added motivation for the mother to quit smoking might one day be tested to determine their GSTT1 status. Because the fetus inherits its genes from both mother and father, the test would determine the likelihood of the baby developing without the GSTT1 gene to detoxify the cigarette smoke.

“A test that indicates the GSTT1 gene is present certainly would not eliminate a baby’s risk of a cleft because many other genetic and environmental factors can be involved,” said Murray. “But the opposite result would give the mother one more compelling reason to quit smoking for her own health and for the sake of her child.”

In the United States, about one in every 750 babies is born with isolated, also called nonsyndromic, cleft lip and/or palate. The condition is correctable but typically requires several surgeries. Families often undergo tremendous emotional and economic hardship during the process, and children frequently require many other services, including complex dental care and speech therapy.

According to Murray, researchers have built a strong statistical case over the past several years that pregnant women who smoke put their unborn babies at greater risk of developing a cleft. The data raised two related questions. “Do genetic variations in the mother influence her own metabolism of the cigarette smoke and its byproducts, thus setting in motion developmental changes that cause the cleft in the fetus? Or do genetic variations in the fetus itself compromise its ability to metabolize the cigarette smoke and cause the cleft?” said Dr. Min Shi, now a scientist at NIH’s National Institute of Environmental Health Sciences and a lead author of the paper.

To find the answers, Murray’s group teamed with colleagues in Denmark to perform a large, complex, and possibly first-of-its-kind international study. The group first assembled a list of 16 genes of interest, each of which encode proteins that plug into various pathways in the body involved in detoxifying dangerous chemicals. “We picked genes that previous evidence shows either are directly involved in cigarette smoke toxicity or are major players in general toxicity management in people,” said Dr. Kaare Christensen, a scientist at the University of Southern Denmark in Odense and an author on the paper.

“These genes tend to be quite variable from person to person in their precise DNA structure, or spelling,” Christensen added. “We wanted to see if any of these variations might adversely affect a person’s ability to break down the toxic products of cigarette smoke.”

Christiansen and his colleagues then turned to their existing database of kids with clefts, their parents, and siblings. In all, the scientists analyzed 5,000 DNA samples from both continents – including 1,244 from children born with clefts. Importantly, the families in Denmark and Iowa provided the opportunity to independently confirm the findings in two distinct populations.

In addition, they had free public access to the NIDCR-funded COGENE project, a comprehensive online database of genes expressed throughout the various stages of development. Working closely with Dr. Mike Lovett at Washington University in St. Louis, one of COGENE’s founders, the database proved especially helpful because cleft lip and/or palate occurs during the first 5-to-12 weeks of development. This meant the scientists had to be sure not only that their genes of interest are expressed during this vital period but are switched on in fetal craniofacial structures. If the genes met both criteria, the investigators said they hoped their subsequent data might point them to a gene-environment interaction.

As reported, the scientists determined from their analyses that the mother provides the toxic environmental exposure, which then can be greatly amplified by the genetics of the fetus to produce the cleft. This marks the first time a gene-environment interaction in clefting has been documented at a molecular level. The data also point the way for future studies to define the specific molecular chain of events that lead to the cleft, vital information to understand and hopefully one day prevent the process.

While sifting through the data, the researchers took particular note of the GSTT gene and its contribution to clefting. The gene encodes one of the body’s approximately 20 different glutathione S-transferase enzymes. These enzymes collectively play roles in common detoxification processes, ranging from chemically altering drugs and industrial chemicals to detoxifying polycyclic aromatic hydrocarbons, a key component of cigarette smoke.

The scientists found that pregnant women who smoked and also carried fetuses that lacked the GSTT1 enzyme were much more likely to give birth to a baby with a cleft. This finding was true in Iowa and Denmark, and they noted in the COGENE database that the gene is highly expressed in developing craniofacial structures. “It may be that the lip and palate can form normally without GSTT1,” said Murray. “But if the chemicals in cigarette smoke challenge the normal development of these structures, fetuses that lack the gene are at a distinct disadvantage.”

Murray and his collaborators continue their genetic analyses. “We now have data from about 350 genes on this cohort of families,” he said. “It’s certainly a more complicated analysis to perform, but we’re working our way through it and hope to have some very interesting data in the months ahead.”

The article is titled “Orofacial Cleft Risk is Increased with Maternal Smoking and Specific Detoxification-Gene Variants,” and is published in the January 2007 issue of the American Journal of Human Genetics. The authors are Min Shi, Kaare Christensen, Clarice R. Weinberg, Paul Romitti, Lise Bathum, Anthony Lozada, Richard W. Morris, Michael Lovett, and Jeffrey C. Murray.

The NIDCR (www.nidcr.nih.gov) is the nation’s leading funder of research on oral, dental, and craniofacial health.

SOURCE: National Institute of Dental and Craniofacial Research

Center For Oral Biology Wins Major Training Grant Renewal

The Center for Oral Biology within the University of Rochester School of Medicine and Dentistry has been awarded $4 million to expand its renowned training program for oral biologists and dentist-scientists. New cross-disciplinary training programs will focus on the basic mechanisms that underlie oral diseases to help students prepare for careers within academia, government and industry.

The curriculum for the “Training Program in Oral Science” will be an integration of basic science research and clinical practice. Programs will focus on the recruitment of dentists who wish to pursue Ph.D. and dentist-Ph.D. degrees, and who want to engage in post-doctoral training. A major component of the program will recruit dental students who wish to coordinate their clinical training with Ph.D. research studies into a joint DMD-DDS/PhD program ( DSTP ).

“A greater number of clinician-scientists who can effectively respond to the growing opportunities in dental, oral and craniofacial research must be generated for society to take advantage of the dramatic advances being made in the biomedical sciences,” said James E. Melvin, D.D.S., Ph.D., director of the Center for Oral Biology and professor of Pharmacology and Physiology. “We intend to be at the forefront of that recruitment effort because of our leadership position in these fields and because of the urgency of the need.”

The training grant ( T32 ) is from the National Institute for Dental and Craniofacial Research, part of the National Institutes of Health. It results from a successful collaboration between the School’s Center for Oral Biology,and its departments of Pharmacology and Physiology, Microbiology & Immunology, Biomedical Genetics, Dentistry, Medicine and Dermatology.

As part of the program, the School of Medicine and Dentistry will offer its Ph.D. programs to undergraduate students at partnering dental schools at the University of Puerto Rico and Marquette University. These dental schools have excellent clinical programs, but no Ph.D. level training.

“We are tremendously excited about the new center as a powerful example of innovative education in translational science,” said David S. Guzick, M.D., Ph.D., dean of the University of Rochester School of Medicine and Dentistry. “More and more we are seeing that oral diseases are linked with other major diseases. The training of dentists to conduct basic and translational research in oral biology will accelerate improvements in oral health.”

SOURCE: University of Rochester School of Medicine and Dentistry