Recent CommentsVitrebond Plus: Reduce Post-Op Sensitivity to Zero?
March 31, 2008
Dr. G. asks:
I have had occasional problems with pos-op sensitivity after doing routine composite restorations. I am considering using a glass ionomer base in deeper cavity preparations. Vitrebond Plus (3M ESPE) glass ionomer base material has just come out and looks easy to dispense, mix and light cure. Some of my colleagues that use glass ionomer bases claim that it reduces post-op sensitivity to almost zero. Before I start using this I just wanted to find out if any of you have used this and what were your impressions. Is the post-op claim accurate? Thanks.
SpiraPost: Little Metal Fibers Coming Off Post?
March 30, 2008
The advertisement for Spirapost (Zenith Dental) shows all these little metal fibers coming off the post that are supposed to engage the composite core. This kind of makes sense for retention of the core material. But has anybody tried this technique? Are those little metal fibers sharp and can they puncture a glove? Is the central metal post thick enough and strong enough?
Editors Note:
According to Zenith:
“The innovative new Spirapost PFS (Poly Fiber Strands), exclusively from Zenith Dental, naturally flexes to conform to the shape of the canal, to offer the benefits of a custom fit for all root canal configurations. Due to its unique design, Spirapost is able to adapt to the irregularities of the canal, so it minimizes the removal of tooth material. Non-technique-sensitive and highly esthetic, Spirapost is simply the most advantageous dental post now available.”
Massad Impression Technique
March 24, 2008
Anon. asks:
I just took Dr. Joseph Massad’s course on making impressions for complete dentures. He uses unique trays that he has designed for the edentulous arch that are disposable and made out of plastic. You can heat them and then mold them to the desired shape. You can trim them easily with a vulcanite bur. He teaches a multi-step protocol for using different viscosity polyvinylsiloxane impression materials to make the final impression. Have any of you tried his trays and used his impression technique? What is your experience?
Editor’s Note: According to Dentsply:
“With the Massad edentulous impression tray, Aquasil Ultra Smart Wetting impression material and the Massad Technique, accurate custom tray impressions can be obtained in one visit. In the past, edentulous impressions were either too rigid or too wet. Rigid material compresses the soft tissue while very wet material doesn’t capture the needed muscular detail. The marriage of the Massad impression tray and technique and Aquasil Ultra impression material has resolved both of these issues.Joseph Massad, DDS, has invented an impression tray and technique which allows the usage of multiple viscosities of Aquasil Ultra impression material in one disposable tray - capturing all the detail needed to create a perfectly fitting full set of dentures. When used with the Massad technique and tray, Aquasil Ultra impression material affords the clinician the optimal outcome.”
Spit Tests: Will Your Practice Soon Be Offering These?
March 24, 2008
Will your practice soon be providing Spit Tests to patients?
According to some new research, one day soon patients may spit in a cup, instead of bracing for a needle prick, when being tested for cancer, heart disease or diabetes. A major step in that direction is the cataloguing of the “complete” salivary proteome, a set of proteins in human ductal saliva, identified by a consortium of three research teams, according to an article published today in the Journal of Proteome Research. Replacing blood draws with saliva tests promises to make disease diagnosis, as well as the tracking of treatment efficacy, less invasive and costly.
Saliva proteomics and diagnostics is part of a nationwide effort to create the first map of every human protein and every protein interaction, as they contribute to health and disease and as they act as markers for disease states. Following instructions encoded by genes, protein “machines” make up the body’s organs and regulate its cellular processes. Defining exact protein pathways on a comprehensive scale enables the development of early diagnostic testing and precise drug design. In the current study, researchers sought to determine the “complete” set of proteins secreted by the major salivary glands (parotid, submandibular (SM) and sublingual (SL)). Recent, parallel efforts that mapped the blood (plasma) and tear proteomes allows for useful comparisons of how proteins and potential disease markers are common or unique to different body fluids.
“Past studies established that salivary proteins heal the mouth, amplify the voice, develop the taste buds and kill bacteria and viruses,” said James E. Melvin, D.D.S., Ph.D., director of the Center for Oral Biology at the University of Rochester Medical Center, and an author on the paper. “Our work, and the work of our partners, has shown that salivary proteins may represent new tools for tracking disease throughout the body—tools that are potentially easier to monitor in saliva than in blood,” said Melvin.
New Definitions for Saliva
To describe the results of the current study, it is important to note that the definition of saliva is evolving. Saliva once referred to everything in oral fluid, including: bacterial waste products, dead cells that had shed from mucous membranes and substances oozing from gum crevices. Among researchers today, however, the term saliva is increasingly reserved for just the salivary gland secretions (ductal saliva). The new definition is significant because of the emerging theory that the mix of proteins in ductal saliva tracks closely with that of blood, making saliva a potential diagnostic stand-in for blood.
How the Study was Conducted
To construct a credible protein list for saliva, the teams used competing techniques both to capture the greatest number of protein candidates for the list and to lend extra credibility to those found using different methodologies. Each team subjected saliva collected from patients to some form of mass spectrometry, which determines the identity of proteins based on measurements of their mass and charge. Saliva was collected from 23 adults of several races and both sexes. Although small, the set of study subjects was large enough to serve as a baseline list for near-future comparisons between healthy people and individuals with major diseases, researchers said.
Using mass spectrometry techniques, three teams at five institutions identified 1,166 proteins in parotid and submandibular/sublingual saliva. The results indicated that more than a third of saliva proteins were found in the blood proteome, as well. Comparison of these proteins against known protein pathways and other proteomes provided a first glimpse of the function of the core proteins. In addition, a number of the salivary proteins were found to match proteins with known roles in Alzheimer’s, Huntington’s and Parkinson’s diseases; breast, colorectal and pancreatic cancer; and type I and II diabetes. Specifically, a majority of the proteins were found to be part of signaling pathways, which is central to the body’s response to (and thus diagnosic of) system-wide diseases, researchers said.
Determining the salivary proteome is only the first step toward salivary-based diagnosis and treatment. These findings provide crucial protein information that is already being incorporated into microarray technology, a high-speed test that can determine the levels of multiple proteins, during disease progression. Related work is underway under within the NIH-funded Bioengineering Nanotechnology Initiative to design biochips, nano-scale computer chips packed with salivary protein chains. Protein probes on the chip react with proteins in a saliva sample, say from the mouth of someone with oral cancer, and inform a computer about which proteins are present.
“We believe these projects will dramatically accelerate diagnosis and improve prognosis by treating diseases at the earliest stages,” said Mireya González Begné, D.D.S., Ph.D., research assistant professor of Dentistry in the Center for Oral Biology at the Medical Center. “Researchers have already shown that saliva proteins can be used to detect oral cancer and HIV infection. We think this list will soon expand to include leading causes of death like cancer and heart disease, which, if caught early, are much more likely to be successfully treated.”
Source:
Contact: Greg Williams
University of Rochester Medical Center
Dental Offices a Major Source of Neurotoxic Mercury Waste?
March 23, 2008
What do you make of the latest research that mercury entering drain water from dental offices is a potential source of toxic mercury? The full story is below.
Mercury is a large component of dental fillings, but it is not believed to pose immediate health risks in that form. When exposed to sulfate-reducing bacteria, however, mercury undergoes a chemical change and becomes methylated, making it a potent, ingestible neurotoxin.
While the major source of neurotoxic mercury comes from coal-fired electric power plants, researchers at the University of Illinois at Chicago and at Urbana-Champaign say mercury entering drain water from dental clinics and offices is also a source.
“We found the highest levels of methyl mercury ever reported in any environmental water sample,” said Karl Rockne, associate professor of environmental engineering at UIC and corresponding author of the study that appeared online March 12 in the journal Environmental Science and Technology.
Working with James Drummond, UIC professor of restorative dentistry, Rockne gathered waste water samples in collection tanks generated from both a single-chair dentist’s office and a 12-chair dental clinic to check for methyl mercury.
Water collected was allowed to settle. Clear layers above the settled particles were then analyzed for presence of methyl mercury. Fine, slow-settling particles of mercury get into the waste water mostly after dentists use high-speed drills to remove old amalgam fillings. The numerous fine particles the drilling produces provide an ample source of exposed mercury surfaces, making them prime targets for sulfur-reducing bacteria that commonly live in anaerobic conditions and are known to methylate mercury.
“It appears to be produced partially, if not fully in the waste water, and it’s being produced very rapidly,” said Rockne, adding that it was significant this was happening before the particles were getting into sewers, where sulfur-reducing bacteria thrive.
The finding raised the question whether the culprit bacteria were living in the mouths of dental patients. “We don’t have the answer,” Rockne said.
Based on their sample studies, the researchers estimate that 2-5 kilograms, or up to 11 pounds, of methyl mercury could be entering the public water supply of the United States each year from dental waste water. While this may not seem like much, methyl mercury is highly toxic in minute amounts.
When in waterways, methyl mercury tends to get biomagnified up the food chain, moving from algae and phytoplankton to fish and, ultimately, to humans.
While surprised by the level of contaminants found in the study, Rockne says follow-up research is necessary — then, possibly, some basic engineering.
“Amalgam separators are a good first step, but maybe something else is necessary downstream to prevent further methylation and prevent further soluble mercury from getting through the system,” he said.
“We have to take more steps to prevent the problem from occurring in the first place,” he said. “We’re dealing with a pipe — a control point. As an engineer, I see this as a problem that is tractable — something we can definitely do something about.”
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Source:
Contact: Paul Francuch
312-996-3457
University of Illinois at Chicago
Will the Femtosecond Laser Change Dental Procedures?
March 21, 2008
An ultra-fast, ultra-intense laser, or UUL, with laser pulse durations of one quadrillionth of a second, otherwise known as one femtosecond, could change dentistry and other medical procedures.“The femtosecond laser has now entered the era of applications. It used to be a novelty, a fantasy,” said University of Missouri researcher Robert Tzou, the James C. Dowell professor and chairman of the department of Mechanical and Aerospace Engineering. “We are currently targeting the areas of life-science and bio-medicine.”
What makes the femtosecond laser different from other lasers is its unique capacity to interact with its target without transferring heat to the area surrounding its mark. The intensity of the power gets the job done while the speed ensures heat does not spread. Results are clean cuts, strong welds and precision destruction of very small targets, such as cancer cells, with no injury to surrounding materials. Tzou hopes that the laser would essentially eliminate the need for harmful chemical therapy used in cancer treatments.
“If we have a way to use the lasers to kill cancer cells without even touching the surrounding healthy cells, that is a tremendous benefit to the patient,” Tzou said. “Basically, the patient leaves the clinic immediately after treatment with no side effects or damage. The high precision and high efficiency of the UUL allows for immediate results.”
Practical applications of this type of laser also include, but aren’t limited to, the ability to create super-clean channels in a silicon chip. That process can allow doctors to analyze blood one cell at a time as cells flow through the channel. In dentistry, the laser can treat tooth decay without harming the rest of the tooth structure.
Associate Professor Yuwen Zhang and Professor Jinn-Kuen Chen recently received a grant from the National Science Foundation to use the laser to “sinter” metal powders—turn them into a solid, yet porous, mass using heat but without massive liquefaction—a process which can help improve the bond between joint implants and bone.
“With the laser, we can melt a very thin strip around titanium micro- and nanoparticles and ultimately control the porosity of the bridge connecting the bone and the alloy,” Zhang said. “The procedure allows the particles to bond strongly, conforming to the two different surfaces.”
Tzou said the installation of a new laser laboratory at MU will enable research teams to “aggressively pursue success at a national level.” The femtosecond laser lab, components of which were installed in January, was made possible through a gift from engineering alumnus Bill Thompson and his wife Nancy. Tzou noted that the arrival of the lab at MU has initiated additional funding requests that will utilize the new femtosecond laser in research. Zhang, Chen and engineering professor Frank Feng also were the recipients of a United States Department of Defense grant to research possible military applications of the UUL.
Tzou said most research with femtosecond lasers, thus far, has focused on engineering materials such as metals and semiconductors. Because of the unique infrastructure at MU, where the college of engineering and the medical school are located on the same campus, Tzou has been able to attract faculty members who have renowned expertise in medicine and laser technology to collaborate.
Source:
Bryan E. Jones
University of Missouri-Columbia
Damage to Teeth from Energy Drinks
March 14, 2008
For more than 10 years, energy drinks in the United States have been on the rise, promising consumers more “oomph” in their day. In fact, it is estimated that the energy drink market will hit $10 billion by 2010. While that may be great news for energy drink companies, it could mean a different story for the oral health of consumers who sometimes daily rely on these drinks for that extra boost.Previous scientific research findings have helped to warn consumers that the pH (potential of hydrogen) levels in beverages such as soda could lead to tooth erosion, the breakdown of tooth structure caused by the effect of acid on the teeth that leads to decay. The studies revealed that, whether diet or regular, ice tea or root beer, the acidity level in popular beverages that consumers drink every day contributes to the erosion of enamel.
However, in a recent study that appears in the November/December 2007 issue of General Dentistry, the Academy of General Dentistry’s (AGD) clinical, peer reviewed journal, the pH level of soft drinks isn’t the only factor that causes dental erosion. A beverage’s “buffering capacity,” or the ability to neutralize acid, plays a significant role in the cause of dental erosion.
The study examined the acidity levels of five popular beverages on the market. The results proved that popular “high energy” and sports drinks had the highest mean buffering capacity, resulting in the strongest potential for erosion of enamel.
According to the study, the popularity of energy drinks is on the rise, especially among adolescents and young adults. Their permanent teeth are more susceptible to attack from the acids found in soft drinks, due to the porous quality of their immature tooth enamel. As a result, there is high potential for erosion among this age demographic to increase.
In fact, Raymond Martin, DDS, MAGD, AGD spokesperson, says he treats more patients in their teens to 20s for tooth erosion. “They drink a great deal more sodas, sports drinks, and energy drinks,” he says. “The results, if not treated early and if extensive, can lead to very severe dental issues that would require full mouth rehabilitation to correct,” says Dr. Martin.
Contact: Stefanie Schroeder
Academy of General Dentistry
Periodontal Disease Leading to Gestational Diabetes
March 1, 2008
A study by a New York University dental research team has discovered evidence that pregnant women with periodontal (gum) disease are more likely to develop gestational diabetes mellitus than pregnant women with healthy gums.
The study, led by Dr. Ananda P. Dasanayake, a professor of epidemiology & health promotion at the NYU College of Dentistry, followed 256 women at New York’s Bellevue Hospital Center through their first six months of pregnancy. Twenty-two women developed gestational diabetes. Those women had significantly higher levels of periodontal bacteria and inflammation than the other women in the study.
The findings, published in the April 2008 issue of the Journal of Dental Research, underscore how important it is for expectant mothers to maintain good oral health.
“In addition to its potential role in preterm delivery, evidence that gum disease may also contribute to gestational diabetes suggests that women should see a dentist if they plan to get pregnant, and after becoming pregnant,” says Dasanayake. “Treating gum disease during pregnancy has been shown to be safe and effective in improving women’s oral health and minimizing potential risks.”
“In the future,” he added, “we can expect to see more research on the link between these two conditions involving other high risk groups, such as Asian and Native American women.”
Gestational diabetes is characterized by an inability to transport glucose — the main source of fuel for the body — to the cells during pregnancy. The condition usually disappears when the pregnancy ends, but women who have had gestational diabetes are at a greater risk of developing the most common form of diabetes, known as Type 2 diabetes, later in life. Hispanics, Asians, and Native Americans are at the highest risk for developing gestational diabetes. Eighty percent of the women in the NYU study were Hispanic.
Inflammation associated with periodontal disease is believed to play a role in the onset of gestational diabetes, perhaps by interfering with the normal functioning of insulin, the hormone that regulates glucose metabolism.
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Source:
Contact: Christopher James
212-998-6876
New York University
The study was supported by a grant from the National Institute of Dental and Craniofacial Research (NIDCR).