Dental News

Dental Pulp Stem Cells Transformed By 'Bad Breath' Chemical

Japanese scientists have found that the odorous compound responsible for halitosis - otherwise known as bad breath - is ideal for harvesting stem cells taken from human dental pulp.

In a study published today, Monday 27 February, in IOP Publishing's Journal of Breath Research, researchers showed that hydrogen sulphide (H2S) increased the ability of adult stem cells to differentiate into hepatic (liver) cells, furthering their reputation as a reliable source for future liver-cell therapy.

This is the first time that liver cells have been produced from human dental pulp and, even more impressively, have been produced in high numbers of high purity.

"High purity means there are less 'wrong cells' that are being differentiated to other tissues, or remaining as stem cells. Moreover, these facts suggest that patients undergoing transplantation with the hepatic cells may have almost no possibility of developing teratomas or cancers, as can be the case when using bone marrow stem cells," said lead author of the study Dr. Ken Yaegaki.

The remarkable transforming ability of stem cells has led to significant focus from research groups around the world and given rise to expectations of cures for numerable diseases, including Parkinson's and Alzheimer's.

In this study, Dr. Ken Yaegaki and his group, from Nippon Dental University, Japan, used stem cells from dental pulp - the central part of the tooth made up of connective tissue and cells - which were obtained from the teeth of dental patients who were undergoing routine tooth extractions.

Once the cells were sufficiently prepared, they were separated into two batches (a test and a control) and the test cells incubated in a H2S chamber. They were harvested and analysed after 3, 6 and 9 days to see if the cells had successfully transformed into liver cells.

To test if the cells successfully differentiated under the influence of H2S, the researchers carried out a series of tests looking at features that were characteristic of liver cells. In addition to physical observations under the microscope, the researchers investigated the cell's ability to store glycogen and then recorded the amount of urea contained in the cell.

"Until now, nobody has produced the protocol to regenerate such a huge number of hepatic cells for human transplantation. Compared to the traditional method of using fetal bovine serum to produce the cells, our method is productive and, most importantly, safe" continued Dr. Yaegaki.

Hydrogen sulphide (H2S) has the characteristic smell of rotten eggs and is produced throughout the body in the tissues. Although its exact function is unknown, researchers have been led to believe that it plays a key role in many physiological processes and disease states.

Too many colleges hurt the prospects of dental students

KOZHIKODE: A glut in dental colleges in the state seems to be giving tense moments to the Kerala chapter of Indian Dental Association (IDA). It has now decided to come out with a campaign called 'No more dental colleges'.
The state already has 20 dental colleges with 1,180 seats in the self-financing sector apart from three government colleges. It is learnt that most colleges have applied for increasing the number of seats.
Dr Shibu Rajagopal, secretary of the state unit of the IDA, said the government is learnt to have given essentiality certificate to seven dental colleges despite the Indian Dental Council chairman writing to the chief minister opposing the move.
The present dentist to patient ratio in the state is 1:3,500, much above the 1:7,500 ratio advised by the World Health Organization (WHO). But if the intake of students is increased, it will add 2,500 new dentists a year bringing down the ratio to 1:1,000. Currently the number of students coming out the state's dental colleges a year is 1,300.

According to Dr George Paul, former president of Association of Maxillofacial Surgeons in India, many dentists have already opted for jobs in BPOs and insurance sector in Bangalore and Hyderabad.

"Eleven years ago it was a prestigious job and people deliberately opted for BDS course. Today dentistry has reached a saturation point with influx of dentists," said A Sahadevan (name changed), a dentist who now works as a graphic designer. According to him, many have left for Canada and other greener pastures. "The meager income has forced many to turn to farming and textile business," he said.
Sanjith George, MDS second year at the Government Dental College, Kozhikode who is also the president of the Calicut chapter of the All Kerala PG Resident Association said many of his BDS batchmates have moved to the Gulf and Australia in search of lucrative offers. "Dental clinics have come up even in rural areas," said Sanjith.

The number of dentists registered in Kerala is approximately 10,000 for a population of 33,387,677 (2011 census).

Dr Dibyendu Mazumder, president, Dental Council of India (DCI), said he is not happy about the state government move.
"I had sent letters to chief ministers of all the states in the country soon after assuming the charge detailing about the present scenario in the dentistry. We have not only achieved the optimum number but also surpassed the world standard henceforth there exist no need of opening new dental colleges," he said.Harrowing times
The state already has 23 dental colleges with 1,180 seats in the self-financing sector 1,300 dentists pass out of these colleges every year.
Present dentist to patient ratio in the state is 1:3,500. The WHO requirement is 1:7,500. There are 10,000 registered dentists in the state








How Bacteria Fight Fluoride in Toothpaste and in Nature

ScienceDaily (Dec. 22, 2011) — Yale researchers have uncovered the molecular tricks used by bacteria to fight the effects of fluoride, which is commonly used in toothpaste and mouthwash to combat tooth decay.

n the Dec. 22 online issue of the journal Science Express, the researchers report that sections of RNA messages called riboswitches -- which control the expression of genes -- detect the build-up of fluoride and activate the defenses of bacteria, including those that contribute to tooth decay.




"These riboswitches are detectors made specifically to see fluoride," said Ronald Breaker, the Henry Ford II Professor and chair of the Department of Molecular, Cellular and Developmental Biology and senior author of the study.
Fluoride in over-the-counter and prescription toothpastes is widely credited with the large reduction in dental cavities seen since these products were made available beginning in the 1950s. This effect is largely caused by fluoride bonding to the enamel of our teeth, which hardens them against the acids produced by bacteria in our mouths. However, it has been known for many decades that fluoride at high concentrations also is toxic to bacteria, causing some researchers to propose that this antibacterial activity also may help prevent cavities.
The riboswitches work to counteract fluoride's effect on bacteria. "If fluoride builds up to toxic levels in the cell, a fluoride riboswitch grabs the fluoride and then turns on genes that can overcome its effects," said Breaker.
Since both fluoride and some RNA sensor molecules are negatively charged, they should not be able to bind, he notes.
"We were stunned when we uncovered fluoride-sensing riboswitches" said Breaker. "Scientists would argue that RNA is the worst molecule to use as a sensor for fluoride, and yet we have found more than 2000 of these strange RNAs in many organisms."
By tracking fluoride riboswitches in numerous species, the research team concluded that these RNAs are ancient -- meaning many organisms have had to overcome toxic levels of fluoride throughout their history. Organisms from at least two branches of the tree of life are using fluoride riboswitches, and the proteins used to combat fluoride toxicity are present in many species from all three branches.
"Cells have had to contend with fluoride toxicity for billions of years, and so they have evolved precise sensors and defense mechanisms to do battle with this ion," said Breaker, who is also an investigator with the Howard Hughes Medical Institute. Now that these sensors and defense mechanisms are known, Breaker said, it may be possible to manipulate these mechanisms and make fluoride even more toxic to bacteria. Fluoride riboswitches and proteins common in bacteria are lacking in humans, and so these fluoride defense systems could be targeted by drugs. For example, the Yale team discovered protein channels that flush fluoride out of cells. Blocking these channels with another molecule would cause fluoride to accumulate in bacteria, making it more effective as a cavity fighter.
Fluoride is the 13th most common element in Earth's crust, and it is naturally present in high concentrations throughout the United States and elsewhere. Its use in toothpaste and its addition to city water supplies across the United States sparked a controversy 60 years ago, and the dispute continues to this day. In the United Kingdom, and in other European Union countries, fluoride is used to a much lesser extent due to fierce public opposition.
The new findings from Yale only reveal how microbes overcome fluoride toxicity. The means by which humans contend with high fluoride levels remains unknown, Breaker notes. He adds that the use of fluoride has had clear benefits for dental health and that these new findings do not indicate that fluoride is unsafe as currently used.
Other Yale authors of the paper include: Jenny L. Baker, Narasimhan Sudarsan, Zasha Weinberg and Adam Roth.
The work was funded by the National Institutes of Health. Breaker is co-founder of a biotechnology company that has licensed intellectual property on riboswitches from Yale.















 New Pain-Free ‘Jab’ Offers Unique Option for Anesthetic Injection



A new pain-free ‘jab’ has recently been designed by a dentist. This ‘jab’ offers a new option for dentists, as it reportedly can deliver anesthetic medication without pain.
The innovative product was created by Dr. John Meechan, a senior lecturer in dental sciences at Newcastle University. He and his team designed a syringe that mixes the anesthetic with a neutralizing solution jest before injection. This mixing action results in an eliminating of the pain sensation that is associated with the anesthetic acidity. “We think our idea has great potential to improve the comfort of dental injections, which will benefit all patients who need anesthetics at the dentist.” said Dr. Meechan. He added “The whole idea was to make dental injections more comfortable for patients and we've done that by changing the delivery system.”




Dr. Meechan continued “One of the things that causes pain during an injection is the solution in the cartridge, because the solution is very acidic and causes a stinging sensation. The needle causes very little pain. The reason the solution has to be acidic is purely and simply for storage purposes. It has to be stored as an acid; otherwise its components lose activity. As soon as you activate the [new] syringe the two solutions mix so you have a neutral solution. This is an unfussy way of doing it.” The new pain-free ‘jab’ received a Medical Futures Innovation Award during a special ceremony in London. Dr. Meechan is looking forward to use the new innovation on a larger scale to provide a new option for anesthetic injection.
Data from the NHS Information Centre indicate that 19% of females and 10% of males experience dental anxiety resulting in the avoidance of dental visits. In a case study titled “Smart Dental Injection System”, the new innovation was introduced for the first time. The pain-free jab features a modified local anesthetic cartridge with a buffer solution that results in less pain sensation during injection. As previously noted, the buffer neutralizes the acidity of the anesthetic, which is the cause of pain, resulting in reduced pain during injection.







 One in Every Ten UK Patients Suffers Dental Phobia, Survey
 


According to a recent survey carried out by the British Dental Health Foundation, one in every ten dental patients suffers extreme dental phobia. This fear is preventing such patients from visiting their dentists, which can result in poor oral health.  The survey also showed that dental phobia was higher among women than men.
The Foundation said that dental phobia might be caused by a bad dental experience that occured during childhood. In addition, certain dental procedures such as tooth drilling and local anesthetic injections create more fear than other dental treatments, 30% and 28% respectively. The Foundation mentioned in a press release that dental phobia is not born with a patient. However, “You develop it and can overcome it”. The Foundation mentioned that earlier exposure to dentists and dental practices during childhood will help in avoiding dental phobia in the future.
“Modern dentistry has evolved to such an extent that it can be almost pain free. Some practices specialize in treating nervous patients. It is worth asking to find your nearest practice. Relaxation and sedation techniques have been proven in helping to overcome dental phobia.” said the Foundation during the press release.
According to the British Dental Health Foundation, while 56% of the public in UK has visited dental NHS facilities, 2% of the population has never been to a dentist before. Few actions can be made for people with dental phobia while visiting their dentist, such as listening to favorite music or going to the dentist with a friend.












 US Experts Recommend Xylitol Sugarfree Gum Against Tooth Decay
                                             


A number of dental professionals in the US have encouraged the use of sugarfree chewing gum to fight tooth decay. It is recommended that high risk patients use this gum during the day to reduce the incidence of decay.
A panel of experts, convened by the American Dental Association (ADA) Council on Scientific Affairs, released a report this month. The report encouraged the use of sugarfree chewing gum, in addition to lozenges and sweets, such as xylitol or polyol compounds. The report also said that varnish with chlorhexidine and thymol may be useful against cavities.




The report added that these procedures were to be followed in combination to a program using fluoride-containing products. The full report can be check at the ADA's Center for Evidence-Based Dentistry (EBD) website. It is also published in the September issue of The Journal for the American Dental Association.
The Dental Hub recently published an article on Xylitol. See: Time-released Xylitol for additional information on xylitol in dentistry. Meanwhile, the panel recommended using a combination of cholrhexidine-thymol varnish on teeth of high-risk individuals. The combination is to be used every 3 months to decrease cavities.







Bacterial Capsule Protects Gum-Disease-Bacteria from Immune Response, Study

 According to a new study, the external capsule of Porphyromonas gingivalis, a microbe causing gum disease, increases the protection and virulence of the bacteria. The study was conducted by a team from Virginia Commonwealth University in Richmond. The results are highlighted in the November Infection and Immunity.
P. gingivalis’ capsule is made of sugar. The capsule covers the proteins of P. gingivalis and thus eliminates the body’s immune response. The research team was headed by Janina P. Lewis from Virginia Commonwealth University. The study involved a comparison between normal and mutant bacteria; the latter did not have the capsule and so before entering the eukaryotic cells and causing infection they were susceptible to an immune response mounted by the mice. Dr. Lewis, "The mutant bacteria activated the host to a greater extent, and thus, were more easily killed by eukaryotic cells. Thus, the capsule protects the bacteria and allows them to survive unnoticed in our bodies."






The study also said that the sugar capsule covering P. gingivalis protects the bacteria from being attacked by phagocytes or marked by dendritic cells. A ‘marking’ by dendritic cells initiates an antibody attack which destroys the bacteria. Bacteria without the capsule were easily indentified and destroyed by the immune response. Dr. Lewis said "Thus, anything that would interfere with generation of capsule, such as drugs interfering with the action of enzymes involved in synthesis of the sugar coat, could be used in treatment of periodontal disease, and importantly, could have broader implications for prevention of more serious diseases,"

 Teeth and Lower Jaw Abnormalities can be Related to Diet Habits, Study
 

 According to a new study, some abnormalities of teeth can be attributed to dietary habits. The relation is more obvious among people living in industrial communities. The study was carried out by a team of anthropologists from the University of Kent. Researchers say that a soft diet could have resulted in a too short or too small jaw relative to tooth size.                                        
Dr Noreen von Cramon-Taubadel, from the University's School of Anthropology and Conservation, and her team conducted the study. They assessed a long-debated hypothesis regarding the effect of diet by saying that the change from a hunter-gatherer human life style to a more agricultural one had a negative impact on the human jaws and skull.
The research team made comparisons between skulls and mandibles of 11 globally distributed populations against different models of genetic, geographic, climatic and dietary variations. It was noted that the shape of lower jaw, along with the shape of the upper palate, seemed to be connected to dietary habits. On the other hand, the shape of the skull appeared to be more connected to genetic variations.
The authors report that the lower jaw shape provided an indication whether the population was more hunter-gatherer or agriculturalist in its life style. Chewing manner was thought to account for the growth and development of different subsistence groups. The comparison showed that hunter-gather populations had longer and narrower lower jaws. This means that teeth had more space for normal eruption. In contrast, agriculturalists mainly had shorter and broader lower jaws which increased the potential for tooth crowding.
Dr. Von Cramon-Taubadel commented on the study. She said “Chewing behavior appears to cause the lower jaw to develop differently in hunter-gatherer versus farming populations, and this holds true at a global level. What is interesting, is that the rest of the skull is not affected in the same way and seems to more closely match our genetic history.”