Skin-like tissue developed from human embryonic stem cells

Dental and tissue engineering researchers at Tufts University School of Dental Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts have harnessed the pluripotency of human embryonic stem cells (hESC) to generate complex, multilayer tissues that mimic human skin and the oral mucosa

Researchers have been seeking methods to grow skin-like tissues outside of the body using new sources of stem cells such as hESC, with the goal of advancing regenerative medicine as a new therapy to replace or repair damaged or diseased tissue. Little is known about how hESC can be developed into the multilayer tissues similar to those that line the gums, cheeks, lips, and other areas in the mouth. We used in vitro tissue engineering techniques to produce skin-like tissues that mimic the lining tissues found in the oral cavity,” said Jonathan Garlick, DDS, PhD, professor of oral and maxillofacial pathology at Tufts University School of Dental Medicine and a member of the cell, molecular & developmental biology program faculty at the Sackler School of Biomedical Sciences at Tufts.
Using a combination of chemical nutrients and specialized surfaces for cell attachment, an hES cell line (H9) was directed to form two distinct specialized cell populations. The first population forms the surface layer (ectodermal, the precursor to epithelial tissue), while the second is found beneath the surface layer (mesenchymal).

Following the isolation and characterization of these cell populations, the researchers incorporated them into an engineered, three-dimensional tissue system where they were grown at an air-liquid interface to mimic their growth environment in the oral cavity. Within two weeks, tissues developed that were similar in structure to those constructed using mature cells derived from newborn skin, which are the current gold standard for tissue fabrication.
“These engineered tissues are remarkably similar to their human counterparts and can be used to address major concerns facing the field of stem cell biology that are related to their clinical use. We can now use these engineered tissues as ’tissue surrogates’ to begin to predict how stable and safe hESC-derived cells will be after therapeutic transplantation. Our goal is to produce functional tissues to treat oral and skin conditions, like the early stages of cancer and inflammatory disease, as well as to accelerate the healing of recalcitrant wounds,” said Garlick.

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Genes that make teeth grow in a row

Ever wonder why sharks get several rows of teeth and people only get one? Some geneticists did, and their discovery could spur work to help adults one day grow new teeth when their own wear out.
A single gene appears to be in charge, preventing additional tooth formation in species destined for a limited set. Scientists at University of Rocheste bred mice that lacked that gene and the rodents developed extra teeth next to their first molars.

Also intriguing is the fact that all the mice born without this gene, called Osr2, had cleft palates severe enough to kill. So better understanding of this gene might play a role in efforts to prevent that birth defect.
Teeth may not be visible until long after birth, but they start to form early in embryo development. Teeth ultimately erupt from a thickened band of tissue along the jaw line called the dental lamina, a band that forms in a top layer of the gum called the epithelium. Scientists have long thought the signals for tooth formation must lie in that tissue layer as well. But the Rochester team found that all the action takes place instead in a deeper cell layer called the mesenchyme.

Dr. Rulang Jiang, a geneticist at Rochester’s Center for Oral Biology showed that the Osr2 gene is like a control switch, it turns on and off the downstream actions of other genes and proteins. In that mesenchymal tissue, the Osr2 gene works in concert with two other genes to make sure budding teeth form in the right spot. Knocking that molecular pathway out of whack causes either missing or extra teeth to result, Jiang showed in a series of mouse experiments.
Time alone will tell us what lies in the future but we sure can hope for a day when becoming edentulous is no longer a concern.

Nasal Spray may end some dental injections

A nasal spray shown to numb the upper jaw is set to be tested in a Food and Drug Administration Phase 3 trial. This will assess the spray’s effectiveness compared to the current “gold standard” of treatment which is painful anesthesia injections.

The upper jaw and the nose with its mucous membranes is supplied for the most of it by the same nerve (Maxillary nerve a branch of the 5th cranial nerve) The nasal spray formula being tested now is related to a drug used by ear, nose and throat physicians when they operate on the nose. Patients who received this anesthetic reported that their upper teeth felt numb, sparking interest in using the anesthetic for dental procedures. The spray is effective only on the upper teeth.

The Phase 3 trial will be carried out later this year at the University of Buffalo dental school and other clinical sites. If the Phase 3 trial is successful, it may mean the end of injections for any dental work performed on the upper teeth.

Halloween- definitely a treat for kids but what about their teeth ?

Does Halloween with its avalanche of candy make it the worst time of the year for children’s teeth ? Not necessarily. The truth about consuming sugars is that frequency is far more important than the amount.

Candy remains a huge part of Halloween for tens of millions of American kids and their candy-buying — or candy-pilfering — parents. The National Confectioners Association says 93 percent of children in the United States go trick-or-treating, and the group estimates that Halloween candy sales this year will top $2.26 billion.
But children — and adults — are less at risk of developing tooth decay if they eat sweets — or even carbohydrate-heavy foods like potato chips and crackers — at mealtimes. This is because when we eat [at meals], the flow of saliva increases and we’re also taking in other liquids that will help wash the mouth out. But if you snack during the day, the teeth are continuously bathed in acid. “If I have four pieces of candy, and I eat all four at one time, my mouth will have acid in it for 30 to 60 minutes. If I eat one each hour, my mouth can be exposed to acid for four hours.” To avoid this parents can have their kids brush their teeth after eating candy. If that’s not possible, have them rinse their mouth with water three or four times after eating to cut down on the acidity in the mouth.
When it comes to Halloween,parents don’t need to get overly concerned about candy and their kids. Halloween will not be the make-or-break factor in whether someone will get a number of new cavities.

Source: Forbes.com

Guard your teeth during sports

Mouth guards aren’t just for the collegiate or professional football player. While losing a tooth might not be the first thing you think about when you lace up your high tops or jump on your bicycle, for anyone who has suffered a severe blow to the jaw, it is an experience they won’t soon forget.

First there is the immediate pain, and depending on the damage done, it can be an injury that requires numerous dental appointments and several thousand dollars to repair. Over the course of an individual’s life, one lost tooth can cost an estimated $10,000-$15,000.

A properly fitted mouth guard is the best protection against such injuries. Customized and manufactured by a dentist, the relatively inexpensive device reduces the risk of dental trauma by 20 to 40 percent. According to the Academy for Sports Dentistry, not only do the major contact sports, such as boxing, football and martial arts, require properly fitted mouth guards, but also less risky activities including basketball, bicycle riding, roller blading, wrestling, surfing and skateboarding.

Despite the fact that mouth guards have been proven effective in preventing dental trauma, most athletes refrain from wearing the device—many claim that it inhibits breathing and talking—and few sports organizations require them as mandatory equipment. One contested benefit of mouth guards is their ability to minimize concussion. Advocates maintain that the device absorbs the force of upward blows to the jaw, reducing trauma to the brain.

In the event of a knocked-out tooth, a quick and informed reaction is key. The tooth should be immediately retrieved. When picking it up, hold it by the crown or enamel portion, not the root, which can be easily damaged. If dirty, it should be rinsed gently, preferably with cold, whole milk or, if unavailable, water. The tooth should not be stored in water under any circumstances because it will damage the root surface. After cleaning, the tooth should be reinserted into place, within five minutes for best results. Research shows that replacing the tooth quickly maximizes the chances the tooth will remain viable. However, if stored in whole milk or in a biophosphonate—a medium specially formulated to preserve root tissue—a tooth can still be reinserted up to one hour after being dislodged.

In the case of children, primary teeth should not be replaced, as this may damage tooth buds of emerging permanent teeth in the gum tissue. You should also ensure you see your dentist as soon as possible in order to ensure you do not have a broken jaw or other possible injuries.

Source:Health News, USC School of Dentistry.

Handy hints to ensure your baby has a healthy smile

I found a few links that answers queries most parents have about maintaining good oral hygiene for newborns. Thought I would share it with you guys. Here they are:

http://www.aapd.org/foundation/hints.asp

http://www.uihealthcare.com/topics/dental/dent4376.html

http://www.aapd.org/publications/brochures/specialcare.asp

http://www.ada.org/public/topics/decay_childhood_faq.asp

http://www.ada.org/prof/resources/pubs/jada/patient/patient_56.pdf

http://www.ada.org/public/media/releases/0701_release01.asp

Study Shows 98.5 Percent Success Rate for Dental Implants

According to new research published in the Journal of Oral Implantology dental implants are 98 percent successful and cause little or no bone loss.

Authors Zeev Ormianer, DMD and Ady Palty, DMD reviewed 60 charts of patients who received a total of 267 implants in two private dental practices in Israel and Germany. They found that 98.5 percent of the implants survived and there was no discernable bone loss in 88 percent of the implant sites. The mean follow-up time was 7.5 years.
The study goal was to determine the level of bone loss over time at the implant sites in the jaw. A key clinical issue was not whether bone loss would occur but how much bone loss should be considered normal and acceptable.
Commenting on the findings, Jamie Lozada, DDS, president of the American Academy of Implant Dentistry said the study adds to growing body of compelling clinical evidence supporting dental implants as the most successful method for replacing missing or compromised teeth

Source:American Academy of Implant Dentistry

Dental Implants

What is a dental implant?
An implant is an artificial replacements for the tooth root and it look like a cylinder or a screw. A typical implant consists of a titanium screw with a roughened surface. It is anchored into the jaw bone and becomes a stable base for one or more artificial teeth. Implants offer stability because they fuse to the bone and this integration helps the replacement teeth to feel more natural than conventional substitutes.

History:
The Mayan civilization has been shown to have used the earliest known examples of endosseous implants (implants embedded into bone). In the 1950s research was being conducted at Cambridge University in England to study blood flow in vivo. These workers devised a method of constructing a chamber of titanium which was then embedded into the soft tissue of the ears of rabbits. In 1952 the Swedish orthopaedic surgeon, P I Brånemark, interested in studying bone healing and regeneration, adopted the Cambridge designed ‘rabbit ear chamber’ for use in the rabbit femur(thigh bone). Following several months of study he attempted to retrieve these expensive chambers from the rabbits and found that he was unable to remove them. He observed that bone had grown into such close proximity with the titanium that it effectively adhered to the metal. Brånemark carried out many further studies into this phenomenon, using both animal and human subjects, which all confirmed this unique property of titanium. He termed the clinically observed adherence of bone with titanium as ‘osseointegration’.

In 1965 Brånemark, placed the first titanium dental implant into a human volunteer, a Swede named Gösta Larsson.There are several types of dental implants; the most widely accepted and successful is the osseointegrated implant which forms a structural and functional connection between the living bone and titanium implant.

Anatomy of a dental implant:
A dental implant designed to replace a single tooth is composed of three parts: the titanium implant that fuses with the jawbone; the abutment, which fits over the portion of the implant that protrudes from the gum line; and the crown, which is created by a prosthodontist or restorative dentist and fitted onto the abutment for a natural appearance.

Implant Placement Procedure:
The surface an implant is treated either by plasma spraying, etching or sandblasting to increase its surface area and thus its integration potential. A small-diameter hole (pilot hole) is drilled into the jawbone at edentulous sites(lacking teeth) to guide the titanium implant in place. Drilling into jawbone usually occurs in several separate steps. The pilot hole is expanded by using progressively wider drills (typically between three and seven successive drilling steps, depending on implant width and length). Care is taken not to damage the osteoblast or bone cells by overheating. A cooling saline spray keeps the temperature of the bone to below 47 degrees Celsius (approximately 117 degrees Fahrenheit). After the hole has been drilled the implant is placed. Once properly torqued into the bone, a protective cover screw is placed on the implant, then the gingiva or gum is sutured over the site and allowed to heal for aprox 3-6 months for osseointegration to occur between the titanium surface of the implant, and the jawbone. There may be some swelling, tenderness or both for a few days after the procedure so pain medication is prescribed to alleviate the discomfort. A diet of soft, cold foods is often recommended during the healing process. In the second stage the implant is uncovered in another surgical procedure, usually under local anesthetic and a healing abutment and temporary crown are placed onto the implant. This encourages the gum to grow in the right scalloped shape to approximate a natural tooth’s gums and allows assessment of the final aesthetics of the restored tooth. Once this has occurred a permanant crown is fabricated and placed on the implant.
An increasingly common strategy to preserve bone and reduce treatment times includes the placement of a dental implant into a recent extraction site. In addition, immediate loading ( a procedure where the abutment is placed during the initial surgical procedure along with the implant) is becoming more common as success rates for this procedure are now acceptable.

Misconceptions Dentists Hear About Teeth Whitening Techniques

Patients often shy away from teeth whitening procedures because of the fears and misconceptions surrounding the techniques. Some of these concerns have been proven to be completely false. Other worries should only be a concern for patients who do not go to certified professionals.

1.Whitening Agents Can Cause Oral Cancer
Most bleaching and whitening products use hydrogen peroxide or carbomide peroxide to remove stains from your teeth. The saliva present in the patients mouths would equalize with these peroxides to dilute and eliminate any possibility of danger.

2.Teeth Whitening Systems Can Damage Tooth Pulp And Nerves
Extremely high concentrations of chemicals can burn the nerve endings and pulp inside the tooth but when used in the right concentrations, there is no way this can happen.

3.Tooth Enamel Is Negatively Affected By Whitening Agents
Early whitening products are at the root of this misconception. These compounds used an abrasive material that would scratch off the stain as well as the surface layers of enamel. New techniques focus on dissolving the stains in the tooth rather than acting like a scratch pad to rub it off.

4.Teeth Whitening Cannot Be Performed On Dental Work
Although this is true with certain procedures, there are other options available to those who cannot benefit from professional whitening. Caps, special fillings, crowns, and bonding do not respond to teeth whitening techniques and the adhesive of these procedures may also be affected. As an alternative, patients can have veneers, bonding, or replace their existing work for the best results. Other dental work such as standard fillings or root canals are not affected negatively by whitening techniques, and respond well to the techniques.

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End in sight for the Dreaded Dentsit Drill

A new technology that spots tooth decay almost as soon as it’s begun promises to reduce the need for drilling and filling.

A preliminary study at King’s College London, where the technique is being developed, found that chemical changes in the tooth could be detected by analysing how light is scattered when a laser is fired at the tooth. Researchers were able to tell healthy teeth from carious teeth because bacteria, responsible for the decay, scatter light in a different way to healthy teeth.
Currently, decaying teeth are uncovered either by visual examination or the use of x-rays, but usually by then, the damage has been done and the decayed area must be drilled out. The new technology, which may be available in dental surgeries in five years from now, is based on Raman spectroscopy most commonly used to distinguish between different chemicals by identifying each molecule’s unique fingerprint. It detects decay simply and painlessly by pointing a tiny optical fibre at the tooth to check on its health.
The downside of developing the machines is the cost and the time it takes to do a scan – 30 seconds can be a long time for any patient to remain perfectly still.

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