Regulators eye link between denture cream and zinc toxicity

Regulators eye link between denture cream and zinc toxicity

Regulatory authorities and dental associations are examining reports that overuse of zinc-based denture adhesives may cause neurological damage. While a direct causal link has not yet been established, dentists are being advised to counsel denture-wearing patients to ensure they aren't using too much adhesive.

The issue has been percolating for several years, but received renewed attention this month following a segment that appeared May 5 on "Good Morning America." In addition, the U.S. FDA has received adverse event reports claiming that cases of zinc toxicity were caused by denture cream overuse, and the agency has confirmed that it has formed a working group to examine the issue.

At issue is the effect that excessive ingestion of zinc over a long period of time can have in depleting the amount of copper in the human body, as copper deficiency can lead to the impairment of various neurological processes. In fact, copper deficiency is a well-established and increasingly recognized cause of neurologic and hematologic disease, and excess zinc has been identified as a source of copper deficiency (Journal of Neurology, January 2004, Vol. 251:1, pp. 111-114).

This is where denture adhesives come in -- some, anyway. While not all denture creams contain zinc, two of the most popular are GlaxoSmithKline's (GSK) Super PoliGrip and Procter and Gamble's (P&G) Fixodent, both of which are zinc-based (GSK also offers a zinc-free version of PoliGrip). The zinc acts as a binding agent that increases the product's hold, according to Jennifer May, a spokesperson for over-the-counter products at GSK.

While zinc is an essential mineral naturally present in many protein-rich foods such as beef, chicken, and nuts, and many supplements and other over-the-counter products such as Zicam (a cold medicine), there are limits to how much a person should ingest on a daily basis, especially with long-term use. The acceptable daily intake is 8 mg for women and 11 mg for men, and more than 40 mg constitutes zinc poisoning, according to the U.S. National Academy of Sciences.

A 2.4 oz (68 gram) tube of Super PoliGrip contains 38 mg of zinc per gram of product, and GSK recommends that a single tube should last approximately six weeks. According to the company's Web site:

You should not use more than the indicated quantity of Super PoliGrip, or use it more often than once per day, to compensate for poorly fitting dentures. You should consult your dentist regularly to maintain proper-fitting dentures.

The Super PoliGrip packaging carries these same recommendations, along with the list of ingredients (topping the list is "poly(methylvinylether/maleic acid) sodium-magnesium-zinc mixed partial salt").

Language on the Fixodent packaging is less explicit; under "Helpful Hints," a highlighted section reads "Don't use too much product at first. It may take a few tries to find the right amount for you!" and "Consult your dentist regularly to ensure proper fitting dentures." There is no list of ingredients on either the Fixodent box or tube; because the FDA has classified denture cream as a Class I device, the manufacturers are not required to list the ingredients.

However, the Fixodent Web site does feature a letter from J. Leslie Winston, D.D.S., Ph.D., P&G's director of professional and scientific relations for North America, which states in part:

A small amount of zinc is used in Fixodent to provide denture hold. This helps the denture stay in place securely so our consumers can eat, chew, and talk more confidently. All Fixodent products undergo rigorous scientific evaluations and safety testing before appearing on shelf and we continue to monitor them once in market. ... The average amount of zinc an average denture adhesive user would ingest from daily usage of Fixodent is less than the amount of zinc in most daily multivitamins and comparable to 6 ounces of ground beef.

English base hyperlinks dentistry and flu

English base hyperlinks dentistry and flu

At this point, 17 activities have been registered in the U.S., according to Eric Chaffin, an lawyer with Bernstein Liebhard in New You are able to City who has so far registered five situations for five individuals, four against GSK in state judge in Chicago and one against both GSK and P&G in government judge.

"In many of these situations, the information is that the litigants use 'excessive amounts' of platter lotion," Chaffin said. "But there is no clear sign from the producers on how much is too much. 'Do not use more than once a day without talking to your dentist' is unforeseen to the guidelines and does not notify customers about prospective zinc oxide harming or birdwatcher lack of."

But in judge documents acquired by "ABC News," GSK and P&G said there is no medical evidence that platter lotion can cause zinc-related diseases. In formerly launched claims, GSK has mentioned that "the the greater part of the zinc oxide in the item continues to be in the sticky and is not launched into the oral cavity. Thus the prospective for intake of zinc oxide through the gum area is little."

At least one review in the literary works clues at a relationship between zinc oxide poisoning and platter lotion. In a research launched last year in Neurology (August 26, 2008, Vol. 71:9, pp. 639-643, initially launched online July 4, 2008), scientists from the School of Florida South west Healthcare Middle chronicled four sufferers they had seen in the division of neurology over a period of three to four decades who were being affected by neurologic irregularities and who all used veneers and revealed serious use of considerable volumes of platter lotion.

The sufferers all had unusually high stages of zinc oxide in their blood vessels, associated with unusually low stages of birdwatcher, the scientists revealed. Regular blood vessels stages of birdwatcher range from 0.75 to 1.45 mg/mL, but stages in these sufferers varied from less than 0.1 to 0.23 mg/mL. An average zinc oxide blood vessels level is 1.10 mg/mL, but these sufferers varied from 1.36 to 4.28 mg/mL.

Each individual used veneers and used two or more pipes of platter lotion weekly "for decades," the scientists revealed, and assessment of past medical, medical, and genealogy and clinical examining did not reveal any other process that could describe the neurologic irregularities. Researchers examined three types of platter lotion used by the sufferers to figure out how much zinc oxide they included (17 to 34 mg per gary of product) and determined that "no other possible description for zinc oxide unwanted or birdwatcher lack of was determined." Copper supplements led to light neurologic enhancement in two sufferers who ceased using platter lotion, the scientists mentioned.

"These sufferers had used platter lotion in considerable volumes on a regular foundation for several decades, going through two pipes per weeks time for at least two to three decades," Sharon Countries, M.D., lead writer on the research, informed DrBicuspid.com.

The reviews have persuaded oral categories to discussion whether they should think about in on the problem. On May 8, the ADA launched a declaration that flows, in part: We are not conscious of any reviews of nerve issues caused by use of a platter lotion following the company's guidelines, nor indeed of any other reviews of nerve or other wellness issues relevant to the use of platter lotion items under any circumstances. ... Patients with decrease suitable veneers should see their oral professional consistently for evaluation and appropriate care, which can decrease the need for platter sticky items.

While the ADA declaration goes on to say "To date, the FDA has not launched any advisory to the community or the career on this problem," a number of activities have been registered with the FDA's Middle for Gadgets and Radiological Health regarding zinc-based platter lotions. On May 12, in reaction to a question from DrBicuspid.com, the FDA launched this statement: FDA has lately become conscious of a research indicating a link between extreme use of zinc-containing platter sticky lotions and birdwatcher destruction, and is convening a working team to analyze the problem more carefully. And while the United states College of Prosthodontics (ACP) has not yet launched a official declaration, the company has included some knowledge content about platter lotions to its Web site.

"One of our issues is that the way this has been provided is it almost appears to be like everyone uses platter glues," said Leslie Brackett, D.D.S., a exercising prosthodontist and the ACP home of community and professional interaction. "Most veneers do not require platter sticky. We want customers to know that if veneers get decrease, the solution isn't just to heap on a lot of platter lotion."

The ACP suggests that platter users should have their veneers re-evaluated every five decades, and that they may need to be realigned, reprocessed, or modified. "The fact is, if your veneers don't fit, you use sticky," Chaffin said. "And if you have a individual come into your office with poor-fitting veneers who doesn't have the means to purchase new veneers, they need to use glues. But people have no idea this zinc oxide problem can present itself."

Computerized details backups not waste time and money

Computerized details backups not waste time and money

IT solutions company Innovative Computerized has released research results showing that dentists can meet or exceed HIPAA protection recommendations, enhance individual solutions, and reduce expenses by switching to on the internet backups for their vital individual details.

By examining the details from customers that have already switched to automated on the internet backups, Innovative Computerized determined that oral methods reduced the likelihood of large government charges, removed wasted work performing and problem solving backups, and minimized storage space expenses relevant to individual records, the company said in an argument. Offices saw immediate reductions in expenses associated with both establishing and maintaining back-up technology; the study showed a net average advantages of $2,550 yearly on storage space media and work expenses alone.

"Prior to shifting clients to the secure on the internet back-up service, over 20% of the assistance calling our help desk received were relevant to back-up verification and problem solving. Those assistance calling have been removed for on the internet back-up users. The staff can be confident that their details is safe in the event of a catastrophe, and the likelihood of breaking HIPAA back-up protection recommendations is removed," said John Moore, founder and CEO of Innovative Computerized, in the discharge. "With HIPAA charges increased to $250,000, it is practical to hire a company now. You'll preserve immediately on work and storage space while gaining satisfaction."

To encourage methods to enhance their catastrophe recovery plans, for a short while, Innovative Computerized is offering 100 GB of on the internet storage space for the price of 50 GGB, according to the news launch. The British Dental Health Base is warning that bad dental cleanliness could increase the spread of the H1N1 flu, according to the Dollars Usher in paper.

Surveying Britons about their oral routines, the basis discovered many picking their teeth with whatever they discovered lying around, including fingernails, bank cards, paperclips, screwdrivers, earrings, and screwdrivers, the paper revealed.

That's a perfect way to introduce pathogens into the body, said the foundation's us president, Nigel Jackson. "Hygiene warnings have been explained ever since the swine flu outbreak, and it is worrying that these routines have been revealed as the numbers affected by flu continuously increases," he told the Dollars Usher in.

Hailed as a leader for offering nearly universal healthcare protection, Massachusetts is mulling proposals to lessen its protection -- starting with oral advantages, according to an article in the Republican paper.

Faced with a steep fall in revenues because of the recession, the state Senate last week proposed to fall oral protection for 700,000 grownups, the paper revealed.

The cuts would include protection for 600,000 grownups getting State medicaid programs advantages for a advantages of $47 million, according to the report. Another 89,000 grownups who make too much cash to qualify for State medicaid programs but still can'

NIH grant to fund oral-health computer game

NIH grant to fund oral-health computer game

Firsthand Technology has received a $3.4 million Small Business Initiative Research grant from the National Institutes of Health (NIH) to research the effectiveness of interactive computer games to change the oral health habits of children, according to the company.

Firsthand and the department of dental public health sciences at the University of Washington School of Dentistry in Seattle are developing a multiplayer, stereoscopic 3D action game to engage children ages 8-12 in the world of bacteria and biofilms with the goal of improving oral health habits. The game will be offered in both English and Spanish.

"There is a whole world in kids' mouths that they know almost nothing about," said Ari Hollander, CEO, technical director, and principal investigator at Firsthand, in a press release. "We have new information and new and exciting science on the dynamics of tooth decay and its prevention. But we're not just trying to teach kids about this -- we believe our immersive game will change their behavior. We are using our experience in virtual reality and game design to create a game that meshes the physicality of the Wii with the engagement of stereoscopic 3D movies."

The game will be the centerpiece of a hands-on, interactive museum exhibit with its public debut at the Pacific Science Center in Seattle in early 2010, according to Firsthand. Later, the exhibit will be converted into a traveling exhibit for science centers across the U.S., as well as around the world.

On behalf of the American Dental Education Association (ADEA), James Swift, D.D.S., will testify on March 18 in support of dental education and research programs before the U.S. House Appropriations Subcommittee on Labor, Health and Human Services, Education, and Related Agencies.

Dr. Swift, currently the immediate past president of the ADEA and the director of the division of oral and maxillofacial surgery at the University of Minnesota School of Dentistry, will present the association's fiscal year 2010 budget recommendations for the Title VII health professions education and training programs, the National Institutes of Health (NIH) and the National Institute of Dental and Craniofacial Research (NIDCR), the Dental Health Improvement Act, the Oral Health Program at the Centers for Disease Control and Prevention (CDC), the National Health Service Corps (NHSC), and the Ryan White CARE Act.

According to an ADEA press release, Dr. Swift will urge Congress to provide $16 million for general dentistry and pediatric dentistry residency training grants; $33.2 billion for NIH, including $440.9 million for the NIDCR; $117 million for the Title VII diversity programs; $235 million for the National Health Service Corps; $10 million for the Dental Health Improvement Act; $17.5 million for CDC's Oral Health Program; and $19 million for the dental programs included in the Ryan White CARE Act.

Can caries detection devices prompt overtreatment

Can caries detection devices prompt overtreatment

A group of international researchers set out to evaluate whether having results from multiple detection methods influences dental treatment decisions for incipient caries lesions on occlusal surfaces. Led by Dr. Antonio Carlos Pereira of the Piracicaba School of Dentistry in São Paulo, Brazil, the team compared visual assessment of 96 extracted permanent molars to data obtained using four additional caries detection methods -- bitewing radiographs, electric conductance measurement (ECM), quantitative light fluorescence (QLF), and laser fluorescence (LF, specifically Diagnodent by KaVo Dental) -- on the same teeth.

Three examiners were used -- all university teachers with up to four years of experience in clinical practice. Prior to participating in the study, they underwent six hours of training: two hours of theoretical training and four hours of practice on extracted teeth.

They first examined the teeth using ECM, then performed a visual exam (without an explorer) and made a treatment decision during the same session. One week later, they performed the radiographic, LF, and QLF examinations. Three weeks after that, they were asked to re-evaluate the teeth and their original treatment recommendations using the additional data obtained with the caries detection devices.

While only slight improvement in the percentage of correct diagnoses was seen when the additional detection methods were used, "a drastic effect" on treatment choice was observed, the researchers stated. In particular, by having results available from multiple detection methods, the choice of invasive treatment -- versus no treatment or preventive/noninvasive treatment such as applying a sealant -- increased "substantially," they noted.

Overtreatment existed at two levels, they added: applying noninvasive treatment to sound teeth and applying invasive treatment to teeth with enamel lesions.

"The former is 'harmless' although costly, and the second is disastrous," the researchers wrote.

In the long run, they concluded, having data from multiple methods did not improve the accuracy of the examiners in detecting early occlusal caries lesions, but it had a "great influence" on the number of surfaces indicated for operative treatment.

The study has other implications as well, according to Dr. Pereira.

"In my opinion, this study shows that each diagnostic method has different characteristics," Dr. Pereira stated in an e-mail interview with zetadental.com.au "Diagnodent has a high sensitivity for initial caries, but also a high level of false positives. ECM is great for dentin caries but fails at the enamel level. Professionals are [encouraged] to understand the new knowledge of caries diagnostic methods and use them, keeping in mind that most caries are at the incipient level and thus prone to preventive treatment."

Douglas Young, D.D.S., M.S., M.B.A., an associate professor at the University of the Pacific School of Dentistry, agrees.

"This study showed that all the different technologies tested didn't necessarily increase correct diagnoses but did prompt them to treat sooner and more aggressively," he said. "It is my understanding that this study was done before the ICDAS [International Caries Detection and Assessment System] ... came out, and it would be interesting to include the ICDAS coding system in a similar study and compare results. The technologies are getting more specific, and each different technology looks for different things; for example, some look for changes in light refraction while others measure fluorescence signals coming off the teeth."

One real problem, Dr. Young added, is that aggressive marketing literature often uses the term "caries" improperly, which makes the clinician think the caries detection device is picking up "decay" earlier so they should restore earlier. "But that is not necessarily true," he said.

Rather, because the devices might be detecting demineralization rather than true decay or infected dentin, clinicians need to fully understand the particular technology they are using and realize that it is only an adjunct in decision-making. Sometimes a more conservative preventive approach could be considered first, Dr. Young suggested.

"The question then becomes, that given that the morphology of the pits and fissures make cleaning them problematic, what is the most minimally invasive way to help prevent cavitation?" he said. "The caries risk of the patient and the extent and activity of the lesion often determine if treatment is optional or elective. It is important to understand that prevention is up to the patient and that, in many cases, we should be giving them options, not dictating treatment. In many cases, all we need to do is to clean out these fissures and seal them so they don't pick up decay. But too many dentists are overly aggressive when it comes to deep restorations and aggressive prepping for sealants."

One option is to rethink the sealant procedure and place a conventional (no resin) glass ionomer as a long-term, fluoride-releasing surface protectant, Dr. Young said.

"Seal and fluoride release prevent decay, which may be more important than retention, bond strength, or even longevity for some patients," he said. "Just tell patients when the fluoride (the glass ionomer) is gone you will put some more on." This approach especially makes sense for newly erupted teeth where you do not want to prep or place a resin-based sealant that will inhibit further maturation (mineralization) of the occlusal surface, he added.

"Dr. Hien Ngo and others have shown that glass ionomers are semipermeable to some ions and have properties very similar to remineralization underneath them. To me, this is the best answer for many people, but it requires re-educating clinicians and patients alike about the treatment objective," Dr. Young concluded.

The 3 (unexpected) keys to successful e-mail marketing

The 3 (unexpected) keys to successful e-mail marketing

Isn't it hard to keep writing all these e-mails? And can you have someone else do it for you?

Let me use this column to talk about some of the objections to what I suggested in a previous column -- that is, to e-mail as often as once a day if possible, to be very informal, to bring up and deal with anxiety and negatives, and to close every e-mail with an offer.

First, the matter of frequency. It is a fact that some people hate getting an e-mail from you every day. In fact, they will unsubscribe from your list if you mail them every day.

Yet, mailing every day is the single most effective thing most dentists can do with their list.

Why?

First, people build a relationship with you because they hear from you so often.

Second, they remember when they subscribed. They are not likely to complain about your e-mail to their e-mail provider, so you are less likely to be blocked.

Third, and most important, your buyers are people who will like and trust you. By turning off some people through frequent e-mail, you will turn on others, who will like you a lot.

Frequency is a fantastic tool for effective e-mails.

Now, about how hard it is to write these e-mails. I suggest you dictate into a USB recording device. Or use a service like zetadental.com.au that lets you dictate into your cell phone, then they transcribe and e-mail for you. So easy!

In fact, you should write like you talk. People will love you. Or they'll hate you and unsubscribe. Big deal. You want to be polarizing so you get those rabid fans. And you can only do that by being really, really you.

Dental patients see you as their friend (or not). It's a relationship to them and to you. If they like you through your e-mails, they will like you in person. And you will like them. The only way to have this honest mutual like is for you to really project your personality. And that means some people off will be turned off.

Take my articles. Some people hate them. They think I am a big promoter and that I encourage doctors to oversell to their patients. These folks hate selling. But other folks like my articles, and they like doing business with me.

I polarize and that way I have passionate customers. I also turn off some people, and they stay away, which is fine with me.

Get it?

This leads to the third question: Do you have to do this all yourself?

I have figured out a way for you to subcontract the whole kit and caboodle, this matter of list building and e-mail marketing and all. But you really should do it all yourself.

I'm going to put on a free webinar soon in which I will share everything I know about advertising and e-mail marketing. Then you really can do it yourself.

Apex Dental Materials

Apex Dental Materials

Another problem with the newer systems is that combining primer and adhesive or primer and etch results in primer being applied to enamel. Surpass (Apex Dental Materials) and All-Bond SE (Bisco) are the only newer-generation products Dr. Brucia has found that have no solvent in the adhesive. "I absolutely would never want primer on enamel," he said. "Dentin primer does nothing but get in your way."

The solvent in the primer doesn't allow adhesives to cure. With fourth-generation products, in which the primer, etch, and adhesive are separate, you can remove the solvent by air thinning the primer until the movement of fluid stops. "When you mix primer and adhesive together, no matter how good your technique is, 25% of what you have left is solvent," Dr. Brucia said.

Light also helps remove the solvent, he noted. "If you light assist the evaporation of your primer, your bond strength will routinely go up 20%. I have tested this for years. The added amount of time and heat will give you a much better adhesion," he said.

A problem with sixth-generation products (in which the primer and etch are in one bottle, the adhesive in another) is that the acids aren't as effective for etching, Dr. Brucia said. Five-amino salicylic acid, citric acid, and nitric acid are used because they neutralize themselves in the mouth, eliminating the need for rinsing.

But phosphoric acid is better for etching, Dr. Brucia said. "I use phosphoric acid on everything. If you were to take my phosphoric acid away from me, you might lose a finger."

The differences add up starkly in bench tests, he said. With his fourth-generation OptiBond, PermaQuik, Scotchbond and All-Bond, he can instantly achieve 40 megapascals (MPa) of bond strength, and 72 MPa after 24 hours. By contrast, with the newest products, he can only achieve 10-15 MPa.

As further evidence that fourth-generation products last longer, Dr. Brucia cited an article in Dental Materials (July 2000, Vol. 16:4, pp. 285-291) that found that the "three-step resin adhesive and the RMGIC [resin-modified glass ionomer cement) showed clinically acceptable retention rates, while a high failure rate was registered for the one-bottle adhesive."

"I would still rather have a 12-year-old bonding agent and a 20-year-old composite in my inventory than the newer systems today," Dr. Brucia concluded.

Not everyone agrees that bonding strength has declined with the newer systems. Junichi Ohtsuki, product manager for Kuraray America, acknowledged that seventh-generation adhesives "are not perfect yet." But he insisted that "The sixth generation is the best bonding agent for relieving sensitivity." The fourth generation, he said, "is similar in strength, but it's technique-sensitive."

Asked for evidence to back up his claims, Ohtsuki provided DrBicuspid.com with three articles from peer-reviewed journals. Of theses, one dealt only with the consequence of mistakes in technique. The other two actually supported Dr. Brucia's position. For example, a September 2005 review by Peumans et al in Dental Materials concluded that, compared to fourth generation systems, "The clinical effectiveness of two-step etch-and-rinse adhesives was less favorable, while an inefficient clinical performance was noted for the one-step self-etch adhesives" (September 2005, Vol. 21:9, pp. 864-881).

Ohtsuki also provided a symposium paper speculating on hypothetical advantages of "self-etch" (later than fourth-generation) adhesives. Finally, he supplied two articles from Gordon Christensen's CRA Newsletter, but only one (November/December 2003, Vol. 27:11/12, pp. 1-5) reported tests of a fourth-generation product: All-Bond 2 (Bisco). The anonymous authors gave this product a bond strength of 26.5 ± 6.3 MPa on enamel and 36.1 ± 4.9 MPa on dentin.

These researchers found several other recent-generation products stronger. They rated two fifth-generation products the highest in strength. Prime & Bond NT (Caulk/Dentsply) got the highest enamel bond strength rating (46.3 ± 9.8 MPa), while OptiBond Solo Plus SEP got the highest dentin bond strength rating (59.5 ± 6.9 MPa).

On the other hand, Douglas J. Brown, D.D.S., senior manager for clinical affairs at Bisco, acknowledged that the fourth-generation systems have clear advantages. "The evidence has shown that they are stronger and longer-lasting than the self-etches," he said.

The only advantages to the newest products -- particularly the one-step systems -- are speed and convenience. In some instances, such as placing a restoration in an impatient child, that speed might be worth the loss of durability, Dr. Brown argued.

And even Dr. Brucia acknowledged that in situations in which strength is not at a premium, the newest systems might be useful. Overall, though, he warned that many dentists would pay the price for taking the easy route.

"I'm too busy to have sensitivity," he said. "I'm too busy to have failures."

Old-style adhesives are better, researcher says

Old-style adhesives are better, researcher says

Violins, cathedrals, waffle irons: they don't make 'em like they used to. To that list, Jeff Brucia, D.D.S., co-director of the Foundation for Advanced Continuing Education (FACE), would add dental adhesives.

"Apply the technique of the 1970s," Dr. Brucia told an audience of 400 at the recent ADA annual meeting. "It's not the coolest. It just works."

One goal of the seminar, titled "Restorative Materials Update 2008," was to review "new advancements" in restorative dentistry. But according to Dr. Brucia, there have been precious few advancements for the past few decades -- especially in bonding systems.

"There has not been an improvement," he said. "There has been a different mode of application." In fact, many products and techniques being used today are not as good as those Dr. Brucia's father used, he said. "He never had sensitivity. Why weren't his restorations falling off? Why are ours falling off today?"

Three adhesive makers contacted by DrBicuspid.com -- Ultradent, Bisco, and Kuraray America -- offered varied reactions to Dr. Brucia's observations: a Kuraray spokesperson disagreed, an Ultradent spokesperson declined to comment, and a Bisco spokesperson mostly agreed.

The problem with mixing

Dr. Brucia, who inherited his father's San Francisco practice and is a University of the Pacific assistant professor, has also been paid to lecture to some adhesive companies. But he said he's beholden to none -- and often contradicts them. "The companies don't like me," he said.

One reason is that he insists the art of bonding reached its zenith with what is now called the fourth generation. This system requires three bottles: an etch, a primer, and an adhesive.

The etch is phosphoric acid. The primer is a hydrophilic agent designed to bind well with dentin. The adhesive is a hydrophobic agent that binds well with porcelain and composite.

Examples include All-Bond 2 and 3 (Bisco), Bond-It (Pentron), OptiBond FL (Kerr), Syntac (Vivadent), Scotchbond Multi-Purpose Plus (3M), and PermaQuik (Ultradent). "They work," said Dr. Brucia. "They work. They work really, really, really well."

Subsequent systems have not shown the same bond strength, Dr. Brucia said, citing both his own lab tests and published studies.

Fifth-generation adhesive systems attempt to save a step by combining primer and adhesives in the same bottle. "How do you take something that loves water and put it together with something that hates water?" Dr. Brucia asked. "You make the product very acidic."

He compared the notion to combining shampoo and conditioner in one. Sure, it's more convenient, he said, but it doesn't work as well. "Give me a fifth-generation system and I have to concentrate like no tomorrow to make that stuff work well," he said. "If I make a mistake with this product, I get catastrophic results."

One problem, he said, is that this acidic hydrophilic bonding agent can cause an acid-base reaction when it comes in contact with a dual- or self-cured composite. Unless the composite is cured within two minutes of placement, this reaction can prevent it from ever curing. Another problem is that the acidic hydrophilic bonding agent creates osmotic blistering.

As evidence, Dr. Brucia cited research by Indiana University researchers (Operative Dentistry, May-June 2006, Vol. 31:3, pp. 346-353) that found that later-generation bonding systems were more water permeable.

To cope with these problems, various adhesive companies introduced new materials to add to the restorations in the late 1990s, Dr. Brucia said, but none worked. Later innovations haven't helped much either, he added. "If you go down to the exhibit floor, they'll tell you, 'We've fixed it.' Well, why did [they] break it in the first place?"

More recently, adhesive companies began raising the pH in their products. "I shook my head," said Dr. Brucia. "I said, 'Wait. We needed the acidity to keep the hydrophilic and the hydrophobic products together." And sure enough, research showed that the new products weren't very stable.

Lack of stability particularly plagues the seventh-generation systems, in which etch, primer, and adhesive are all combined in a single bottle, he said, citing a study in the American Journal of Dentistry (April 2006, Vol. 19:2; pp. 111-114).

The single-bottle products are so unstable that they have to be kept chilled. "When we're doing a study, we call up the company and ask if we can get some of the product," Dr. Brucia said. "It arrives packed in ice." But adhesives makers often neglect to inform their customers of this problem. "When is the last time you bought a bonding agent and it came packed in ice?"

Study links herpesvirus with endodontic disease

Study links herpesvirus with endodontic disease

Herpesviruses have long been considered the culprits behind many oral diseases. Now a new study has found a link between endodontic disease and the Epstein-Barr virus. The discovery could lead to the development of new preventive and therapeutic treatments for some endodontic diseases.

Epstein-Barr is a form of herpesvirus and a pathogen found in more than 90% of the world's population. It is associated with many diseases, including infectious mononucleosis, malignant lymphomas, and nasopharyngeal carcinoma.

The new study has found that a large number of dental patients with the inflammatory diseases irreversible pulpitis and apical periodontitis also have the Epstein-Barr virus (Journal of Endodontics, December 2008, Vol. 34:12).

Researchers at the Oregon Health & Science University School of Dentistry wrote that their aim was to ascertain the presence of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), herpes simplex virus 1 (HSV-1), and varicella zoster virus (VZV) in endodontic pathoses. All four forms belong to three different groups of herpesvirus.

The team looked at specimens collected from 19 healthy pulp control patients and 82 patients exhibiting endodontic disease, including those with irreversible pulpitis or apical periodontitis, as well previously treated apical periodontitis. The patients' ages ranged from 15 to 92, with 50 males and 51 females. Specimens were obtained from molars, bicuspids, and anterior teeth.

Researchers studied the DNA and RNA from the specimens to determine the presence of herpesviruses.

EBV DNA was present in patients with endodontic disease in higher percentages (43.9%) compared to the control group (0%), as was EBV RNA (25.6% compared to 0%).

HCMV DNA and RNA were found in high percentages in both endodontic patients (15.9% and 29.3%, respectively) and in healthy controls (42.1% and 10.5%, respectively).

HSV-1 DNA was found in a slightly higher percentage of endodontic patients (13.4%) when compared to healthy controls (5.3%), but these differences were not statistically significant, according to the researchers. No HSV-1 RNA was found in any of the diseased or healthy pulp specimens. Only one patient, exhibiting symptomatic irreversible pulpitis, showed presence of VZV DNA and RNA.

"Our results have indicated that EBV is present in significantly higher frequencies in irreversible pulpitis and apical periodontitis when compared with healthy controls," the authors wrote. "This study supports the premise that EBV, but not HCMV, HSV-1, or VZV, is associated with irreversible pulpitis and apical periodontitis, and may potentially play a role in endodontic disease."

"There have been few prior publications on herpesviruses and endodontic disease -- only one other to my knowledge," said co-author Curtis Machida, Ph.D., a professor in the department of integrative biosciences at the Oregon Health & Science University, in an interview with DrBicuspid.com. "This current study is the first published report linking Epstein-Barr virus and irreversible pulpitis, one prominent form of endodontic disease."

Although the study has statistically significant evidence to prove that the presence of EBV is associated with endodontic pathoses, the fact that it is not found in all endodontic patients allows the interpretation that other microorganisms may serve as co-factors of disease, the researchers noted.

"EBV may represent one important player of irreversible pulpitis, but there are undoubtedly additional co-factors for disease," Machida said. "Endodontic disease is believed to be due to a polymicrobial infection and inflammatory disease. Knowing the full cast of players would obviously and ultimately lead to better and more targeted modes of therapy."

Machida added that the study has been of great interest to academics and professionals within the endodontic field.

Dennis Walling, M.D., an associate professor in the department of microbiology and immunology at the University of Texas Medical Branch, agreed that this is the first study to identify EBV specifically as the herpesvirus associated with endodontic disease. While previous research has linked herpesviruses with endodontic disease, this study extends and strengthens the association with the large number of histologically varied specimens that were studied, he noted.

"The potential significance of finding herpesviruses in periodontal and endodontal diseases is that it forces us to rethink long-held assumptions about the pathogenesis of these diseases originally believed to involve only bacteria," Dr. Walling said. "The interesting idea is that the viruses may act in a way that facilitates bacterial pathogenic potential, perhaps by compromising the local oral defense mechanisms in a way that shifts the host-microbe equilibrium in favor of the resident oral bacteria."

More research is needed to understand the mechanisms, which could lead to the eventual development of new preventive or therapeutic approaches to these diseases.

"However, this area of study still has far too many unanswered questions for anyone to yet know how this finding might be clinically useful," Dr. Walling concluded.

University of Buffalo dental school dean steps down

University of Buffalo dental school dean steps down

The dean of the University of Buffalo School of Dental Medicine is stepping down after serving in his position for seven years, according to a UB Reporter news story.

Richard Buchanan, D.M.D., has previously served in academic and administrative positions at the University of Texas Health Science Center Dental School at San Antonio, New Jersey Dental School, and Baylor College of Dentistry.

"A strong academician in his own right, he has provided the school an important compass in the form of leadership by personal example," said David Dunn, vice president for health sciences, in the news article. "Fortunately, he has agreed to remain in his current position until a national search can be launched and a suitable successor identified and recruited."

 Dentsply International has entered into a definitive agreement with the shareholders of Zhermack of Badia Polesine, Italy, to acquire a majority interest (60%) in the European firm, according to the company. Terms of the deal were not disclosed.

As part of the agreement, the two founders of Zhermack will retain "significant ownership" and continue to manage the business.

Zhermack is a producer of dental impression materials and lab equipment and sells products in more than 100 countries, with an emphasis on Europe, Latin America, Asia, and the Commonwealth of Independent States. The company has manufacturing facilities in Italy and Poland.

"We believe that our polymer-based expertise can contribute to Dentsply's R&D efforts, and as partners, we can continue developing innovative products for the dental profession," said Tiziano Busin, Zhermack's president and founder, in a press release.