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A guide to the management of amalgam in the dentistry environment

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A guide to the management of amalgam in the dentistry environment


Unused dental surgery prescriptions may help fuel opioid epidemic

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the United States is in the midst of a prescription opioid epidemic. Evidence suggests people who abuse prescription opioids often use leftover pills that were prescribed for friends or family members. Now, new research finds over half of opioids prescribed to patients who have dental surgery - such as wisdom tooth removal - are not used.

A report on the study, by researchers at the University of Pennsylvania (Penn) in Philadelphia, is published in the journal Drug and Alcohol Dependence.

The authors suggest if there were more drug disposal kiosks in pharmacies, and if dentists reduced the amount of opioid pills they prescribe following surgery by just a little, it could reduce the mountain of unused pills - and therefore the amount of misuse - significantly.

They estimate - if we translate their findings to the whole U.S. population - that potentially over 1 million opioid pills prescribed to patients following removal of wisdom teeth are unused.

Opioids to relieve pain are often prescribed following surgery or injury, or for health conditions such as cancer.

In recent years in the U.S., there has been a dramatic increase in prescribing opioids for chronic, non-cancer pain, such asback pain or osteoarthritis, even though they carry serious risks and there is no evidence about their long-term effects.

Anyone who takes prescription opioids can become addicted to them. Once addicted, it can be hard to stop. Taking too many prescription opioids can stop a person's breathing, leading to death.

According to the Centers for Disease Control and Prevention (CDC) in 2014, nearly 2 million Americans either abused or were dependent on prescription opioid painkillers. The CDC now refer to the situation as an epidemic.

Since 1999, the number of overdose deaths in the U.S. involving opioids has nearly quadrupled, and we now know, say the CDC, that a driving factor is increase in overdoses from prescription opioid painkillers.

Seventy-nine patients had over 1,000 opioid pills left over

For their investigation, the team looked at prescription opioid use in 79 patients who were prescribed the painkillers following dental impaction surgery.

They were also interested in how specific information about a drug-disposal program in pharmacies might affect the willingness of patients to properly dispose of any unused pills.

The results showed that just 24 hours after surgery, patients were reporting an average pain level of 5 out of 10 while on painkillers. By day 2, just over half (51 percent) were reporting levels of 0-3 out of 10, and by day 5, nearly 80 percent were reporting low levels of pain.

Nearly all the patients (94 percent) were given a prescription for an opioid painkiller. In addition, 82 percent were also given a prescription-strength nonsteroidal anti-inflammatory drug (NSAID), and 78 percent received a prescription antibiotic.

The vast majority of patients (93 percent) did not have post-surgery complications. On average, after 3 weeks, these patients had only used 13 out of the 28 opioid pills prescribed, leaving a total of over 1,000 unused pills. Only five of the patients used all their prescribed opioids.

Co-author Elliot V. Hersh, a professor in the departments of oral & maxillofacial surgery and pharmacology at Penn's School of Dental Medicine, says:

"Results of our study show within 5 days of surgery, most patients are experiencing relatively little pain, and yet, most still had well over half of their opioid prescription left."

Drug disposal centers can make a difference

The team also found that giving patients specific information about a pharmacy-based drug disposal program, in addition to general information, led to a 22 percent increase in patients who either used the facility or planned to use it as a way to dispose of leftover opioid pills.

This was compared with patients who were only given the general information, comprising a hotline to ring and a sheet describing controlled substances and the risks of keeping opioid pills.

The team suggests putting more drug disposal centers in grocery stores, retail pharmacies, and other places patients visit regularly could substantially increase proper disposal of unused prescription opioids.

Another suggestion the team makes is that by just moderately reducing the quantity they prescribe following surgery, dentists and oral surgeons could also potentially reduce surplus opioid pills.


Stem cell manipulation shows promise for cartilage renewal and joint repair

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for people with a type of jaw joint disorder that results from loss of cartilage, the only treatments available address symptoms but do not repair the damaged tissue. Now, a new study of mice suggests stem cells already present in the jaw joint could be manipulated to repair it.

The study, led by Columbia University Medical Center in New York, NY, is published in the journal Nature Communications. The authors describe how manipulating stem cells in the temporomandibular joint (TMJ) of mice with TMJ degeneration led the cells to repair cartilage in the joint.

The researchers also found that transplanting just a single TMJ stem cell into a mouse spontaneously generated cartilage and bone and even began to form a bone marrow niche.

Lead and corresponding author Mildred C. Embree, assistant professor of dental medicine at Columbia, says:

"This is very exciting for the field because patients who have problems with their jaws and TMJs are very limited in terms of clinical treatments available."

Stem cells - immature cells that have the potential to mature into virtually any type of tissue cell - hold great promise for regenerative medicine, where faulty, damaged, or injured tissue is repaired by encouraging new cells to grow.

Alternative to stem cell transplanting

One way to regenerate tissue is to transplant stem cells into the affected area. However, as the authors explain in their paper, this approach can be risky - for instance, the donor cells could be rejected by the recipient's immune system, introduce pathogens, or even give rise to tumors.

An alternative approach that could avoid these risks is the possibility that stem cells already present in the affected area could be induced to make new cells repair the damaged tissue.

Cartilage is a type of tissue that cushions bones and lines the joints to enable smooth movement without damage.

Within the TMJ, the cartilage is of a type called fibrocartilage. This type is also found in the knee meniscus and the discs between the vertebrae of the spine.

Once it is damaged - for instance through injury or disease - fibrocartilage does not regrow or heal, with the result that people suffer permanent disability.

In the United States alone, there are up to 10 million people - mostly women - with TMJ disorders. Children with juvenile idiopathic arthritis can also have stunted jaw growth that cannot be treated with existing drugs. The researchers suggest their findings could lead to new treatments that help these groups.

Suppressing Wnt signals

In their study, Prof. Embree and colleagues - including Jeremy Mao, the Edwin S. Robinson Professor of Dentistry (in Orthopedic Surgery) at Columbia - show for the first time that the "fibrous superficial zone" in the TMJ of mice harbors fibrocartilage stem cells (FCSCs).

They also discovered that a single FCSC transplanted into a live mouse is capable of not only generating cartilage and bone, but also of organizing the microenvironment to support the process - rather like specialized niches in bone marrow.

Moreover, the researchers showed that they could manipulate FCSCs to differentiate into the required cell types by suppressing a type of cell signal called Wnt. They found that overactive Wnt signals disrupt the stability of fibrocartilage and promote degeneration by depleting FCSCs.

The findings could also open up routes to new treatments for repairing fibrocartilage in joints other than the TMJ, including the knees and vertebral discs, as Prof. Embree explains:

"Those types of cartilage have different cellular constituents, so we would have to really investigate the molecular underpinnings regarding how these cells are regulated."


Investigators chart microbial ecology of gingivitis, periodontitis

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the soft tissue of the gums and sometimes even destroys the bone supporting the teeth. An international team of researchers and clinicians has charted the microbial ecology of the mouth at all stages of this progression, in nearly 1,000 women in Malawi. This work is laying a foundation of knowledge that could lead to better oral health. The research is published inApplied and Environmental Microbiology, a journal of the American Society for Microbiology.

The investigators used high-throughput sequencing of the 16S ribosomal RNA (rRNA) gene to take the census of the oral microbiomes. Among much else, they found that a small number of species were associated with periodontitis, but not gingivitis, including members of the genera, Prevotella, Treponema, and Selemonas. "Our findings confirm that periodontitis cannot be considered simply an advanced stage of gingivitis, even when only considering supragingival plaque," said first author Liam Shaw, a PhD student at University College London, United Kingdom.

Periodontitis is diagnosed by measuring the depth of the pockets in the gums next to the teeth. "But diagnosing periodontitis visually is impossible and it doesn't usually give any symptoms until it has developed so far that teeth become mobile, which is very late for any treatment," said coauthor Ulla Harjunmaa, a dentist with a master's degree in international Health, who is a PhD student at the Center for Child Health Research, University of Tampere and Tampere University Hospital, Finland.

Diagnosis requires specially trained dental professionals and expensive equipment, which are seldom available in developing countries, said Harjunmaa. But among other things, in the future, this research may lead to an inexpensive and rapid point-of-care test, based on distinguishing the two conditions' microbiomes. "The research made it possible to tell which differences in bacteria were linked specifically to the deepening of dental pockets - which causes loss of teeth - rather than just to bleeding gums," explained Shaw.

"We're not the first to do this sort of research into periodontal disease, but our study is the largest to be done in such a setting," said Shaw. "There is a great need to find new solutions to prevent these problems everywhere, but especially in this kind of setting." He added that oral infections are very common in Malawi, since there is little awareness about oral health and prevention, and little treatment available.

Some of the techniques used in the research may have wide applications, said Shaw. "Where diseases can have multiple severities and clinical features that are also found in non-disease (like bleeding gums in periodontitis), this kind of modeling will be increasingly important in microbiome research."

Periodontal disease is a major public health problem associated with oral bacteria. In developed nations, approximately half of adults are thought to have moderate periodontal disease, with another 7-15 percent having advanced disease, according to the Centers for Disease Control and Prevention. Additionally, periodontal disease is thought to be a risk factor for cardiovascular disease, diabetes, and other chronic health conditions. Treating gum disease could reduce healthcare costs, as well as hospitalizations, according to a study published in the August, 2014 American Journal of Preventive Medicine.

"The best way to prevent periodontal disesases is by proper tooth brushing twice a day combined with flossing once a day," said Harjunmaa. For smokers, quitting is also critically important to prevention, she said.


Colorectal tumors exacerbated by mouth microbes

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mouth microbes called fusobacteria may use the bloodstream to reach and worsen colorectal tumors through a special sugar-binding protein, study finds.

Colorectal cancer is the third leading cause of cancer-related deaths in the United States when men and women are considered separately, and the second leading cause when both sexes are combined.

While the death rate from colorectal cancer has decreased in both males and females - due to colorectal polyps being found by screening and removed before they can develop into cancer - not enough people are getting screened for colorectal cancer.

In 2014, 65.7 percent of U.S. adults were up-to-date with colorectal cancer screening; 7 percent had been screened, but were not up-to-date, and 27.3 percent had never been screened.

Previous studies by the Garrett Lab at the Harvard T.H. Chan School of Public Health in Boston, MA, have shown fusobacteria to promote the formation of colorectal tumors and exacerbate colorectal cancer in animals. Also, they found that fusobacteria are enriched in human colorectal tissue when compared with neighboring healthy tissue.

According to the Harvard researchers and scientists from the Hebrew University-Hadassah School of Dental Medicine in Israel, this is the first study to shed light on how the microbes from the mouth make their way to the gut, and how they localize to and become abundant in colorectal tumors.

The findings, published in Cell Host & Microbe, demonstrate that fusobacteria use a sugar-binding protein to stick to developing colorectal polyps and cancers, whereby they proliferate and subsequently accelerate the disease.

"As fusobacteria contribute to colon tumor development, revealing the mechanism that guides them to the tumor and why fusobacteria become abundant there might inform ways of blocking this," says co-senior author Wendy Garrett, of the Harvard T.H. Chan School of Public Health and the Dana-Farber Cancer Center.

"Alternatively, and perhaps more importantly, if we know how fusobacteria localize and become enriched in colon tumors, hopefully, we can utilize the same or similar mechanisms to guide and deliver cancer therapeutics to colon tumors," she adds.

Injected oral microbes traveled to colorectal tumor site

Microbes have emerged as a key factor that influences the development and progression of colorectal cancer.

With co-senior author Gilad Bachrach, of the Hebrew University-Hadassah School of Dental Medicine, Garrett suspected that oral microbes might travel through the bloodstream to reach colorectal tumors.

The team examined two mouse models - with either precancerous or malignant colorectal tumors - and injected fusobacteria into their tail veins to test their hypothesis.

The fusobacteria became saturated in the colorectal tumors of both types of mice when compared with the adjacent normal tissue.

Metastatic cancer is cancer that spreads to other parts of the body. When colon cancer spreads, it often spreads to the liver. Like the mouse models, saturation of fusobacteria was also detected in secondary colorectal cancer samples of the liver, but it was not seen in samples taken from tumor-free liver biopsies.

Sugar-binding protein enables fusobacteria to attach to colorectal tumors

Additionally, the researchers discovered from using human samples and mouse models that the Fap2 protein that is located on the surface of fusobacteria recognizes a type of sugar, Gal-GalNac, which is abundant on the surface of colorectal tumor cells.

From experimenting, the researchers learned that Fap2 mediates fusobacterial colonization of colorectal cancer tumors and metastasis.


When paired with the knowledge from recent studies - that Fap2 protein impairs the ability of the host immune system to kill tumor cells - the findings suggest that fusobacteria reaches colorectal tumors through the bloodstream and uses their Fap2 protein to bind to host cells and proliferate tumors, thereby accelerating colorectal cancer.

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