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Sunday, September 30, 2012

Concept of pulp tests !

Dental pulp testing is a useful and essential diagnostic aid in endodontics.Pulp sensibility tests include thermal and electric tests, which extrapolate pulp health from sensory response.
Traditional electronic pulp testers work by passing a current into the tooth and measuring how much current is required to cause a sensation. Unfortunately, the diagnosis is often made on a tooth that has or is near a metal tooth filling, which can change the path of the current in unpredictable ways. Clinically, this has led to false-positive readings. University of Oxford researchers have designed a magnetic analog of this device that aims to alleviate this issue.
                                        Dental pulp tests are investigations that provide valuable diagnostic and treatment planning information to the dental clinician.The most accurate way of evaluating the pulp status is by examination of histological sections of the tissue specimen involved to assess the extent of inflammation or the presence of necrosis as a means of gauging pulp health. Unfortunately in the clinical scenario, these are both impractical and not feasible; hence clinicians must use investigations such as pulp tests to provide additional diagnostic information.

 Pulp Testing Techniques and Effectiveness

A.Thermal Tests






A common misconception is that thermal tests cannot be performed on teeth with crowns or temporary restorations. These teeth can be cold-tested but it may be necessary to leave the cold in place for up to 10 seconds before the patient responds.4 A CO2 ice stick may be used but doing so requires an extensive armamentarium (that is, a gas cylinder and plastic plunger). 

Various cold tests include : 
a.Ice
b.Refrigerant spray
c. Carbon dioxide snow (CO2)


Electric Pulp Test

 Electric pulp testing (EPT) works on the premise that electrical stimuli cause an ionic change across the neural membrane, thereby inducing an action potential with a rapid hopping action at the nodes of Ranvier in myelinated nerves .




In dentistry, an electric pulp test ascertains the vitality of a tooth.
An electric pulp test consists of the following: An electric pulp tester is placed on the tooth to be tested along with a drop of conducting paste. The electric current is gradually increased until the patient signals a sensation, which consists of clicking or buzzing in the tooth. The test is repeated on neighboring teeth and often on the corresponding contralateral tooth. The lowest perceptible current is recorded for each tooth.
No response from a tooth generally indicates pulpal necrosis or dental abscess, which suggests root canal therapy or dental extraction. A very quick response compared to the adjacent teeth generally indicates pulpitis and presages pulp death. Similar response to neighboring teeth suggests a healthy tooth.
 Safety Concerns of EPT
In EPT operation manuals, warnings have been made that the current produced by the testing device may cause danger to patients who have cardiac pacemakers, with the risk of precipitating cardiac arrhythmia via pacemaker interference. This concern is based on a sole animal study , where EPT interfered with a pacemaker fitted in a dog. At the time of that study (the early 1970s), cardiac pacemakers were primitive but as pacemakers have become equipped with better shielding, more recent studies have shown no interference from EPT or similar electrical dental devices .

Summary
It is remarkable that dentistry still relies upon placing cold and tapping on a tooth to diagnose the need for nonsurgical root canal treatment. Although several technological tools can be used to aid in diagnosis, including laser Doppler flowmetry and conebeam tomography, it remains the dentist’s job to use tried-and-true diagnostic methodology and put the pieces of the puzzle together to form a clear diagnostic picture.3,9 Only then can endodontic treatment be undertaken with the knowledge that no harm has been done. 







Friday, September 21, 2012

Japan tooth patch could be end of decay; microscopically thin film that can coat individual teeth

The "tooth patch" is a hard-wearing and ultra-flexible material made from hydroxyapatite, the main mineral in tooth enamel, that could also mean an end to sensitive teeth.

 

A tooth patch, an ultra thin biocompatible film made from hydroxyapatitte, is pictured on September 6, 2012.

Scientists in Japan have created a microscopically thin film that can coat individual teeth to prevent decay or to make them appear whiter, the chief researcher said.
The "tooth patch" is a hard-wearing and ultra-flexible material made from hydroxyapatite, the main mineral in tooth enamel, that could also mean an end to sensitive teeth.
"This is the world's first flexible apatite sheet, which we hope to use to protect teeth or repair damaged enamel," said Shigeki Hontsu, professor at Kinki University's Faculty of Biology-Oriented Science and Technology in western Japan.
"Dentists used to think an all-apatite sheet was just a dream, but we are aiming to create artificial enamel," the outermost layer of a tooth, he said earlier this month.
Researchers can create film just 0.004 millimetres (0.00016 inches) thick by firing lasers at compressed blocks of hydroxyapatite in a vacuum to make individual particles pop out.
These particles fall onto a block of salt which is heated to crystallise them, before the salt stand is dissolved in water.
The film is scooped up onto filter paper and dried, after which it is robust enough to be picked up by a pair of tweezers.
"The moment you put it on a tooth surface, it becomes invisible. You can barely see it if you examine it under a light," Hontsu told AFP by telephone.
The sheet has a number of minute holes that allow liquid and air to escape from underneath to prevent their forming bubbles when it is applied onto a tooth.
One problem is that it takes almost one day for the film to adhere firmly to the tooth's surface, said Hontsu.
The film is currently transparent but it is possible to make it white for use in cosmetic dentistry.
Researchers are experimenting on disused human teeth at the moment but the team will soon move to tests with animals, Hontsu said, adding he was also trying it on his own teeth.
Five years or more would be needed before the film could be used in practical dental treatment such as covering exposed dentin -- the sensitive layer underneath enamel -- but it could be used cosmetically within three years, Hontsu said.
The technology, which has been jointly developed with Kazushi Yoshikawa, associate professor at Osaka Dental University, is patented in Japan and South Korea and applications are under way in the United States, Europe and China.


Banking Baby, Wisdom Teeth For Stem Cells Banking..




New York
June 8, 2005—Baby and wisdom teeth, along with jawbone and periodontal ligament, are non-controversial sources of stem cells that could be "banked" for future health needs, according to a National Institutes of Health researcher who spoke today at the American Dental Association's national media conference. Harvested from the pulp layer inside the teeth, jawbone and periodontal ligament, these stem cells may one day correct periodontal defects and cleft palate, and may help restore nerve cells lost in diseases such as Parkinson's, according to Pamela Gehron Robey, Ph.D., Chief, Craniofacial and Skeletal Diseases Branch, National Institute of Dental and Craniofacial Research of the National Institutes of Health, Department of Health and Human Services. Stem cells have the potential to save injured teeth and grow jawbone.
Regenerating an entire tooth is on the horizon, and years from now, Dr. Robey said stem cells from teeth and jawbo- ne might be used to correct cleft palate, one of the most common birth defects, sparing children multiple surgeries. "As long as a cell has a nucleus, anything is possible," Dr. Robey states. In time, individuals may be able to bank their own stem cells from baby and wisdom teeth, similar to the way umbilical cord blood is stored. At present, commercial facilities to store stem cells from teeth are not available. According to Dr. Robey, the viability of stem cells derived from baby teeth is determined by when the tooth comes out. The longer a loose tooth is left in the mouth to fall out on its own, the less viable it is as a source of stem cells. As research in the field progresses, Dr. Robey hopes that stem cells from baby and wisdom teeth may one day restore nerve cells damaged by diseases such as Parkinson's Disease, one of the most common neurological disorders affecting the elderly.
"The stem cells from jawbone and teeth share a common origin with nerve tissue," Dr. Robey points out. "With the proper cues, researchers may be able to encourage them to form nerve-like tissue which may restore cells that make dopamine, but much more work is needed." Dopamine is a brain chemical that nerve cells need to properly function. To extract the stem cells from teeth, researchers can remove the periodontal ligament, drill into the tooth to remove the crown and then extract the pulp which is placed in an enzyme solution to release the stem cells. From jawbone, cells can be isolated by collecting marrow following a tooth extraction, for example, or by biopsy.
Therapeutic Application
Dental Stem Cells can Differentiate into...

This has Potential Benefit in..
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arrow
Cardiac cells (heart cells)
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Repair damage caused by Myocardial Infarction (Heart Attack)
Neurones (nerve cells)
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Repair due to stroke or other degenerative diseases
Myocytes (muscle cells)
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Repair loss due to crush-injuries or other degenerative diseases
Osteocytes (bone cells)
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Repair fractures and other joint/bone diseases
Adipocytes (fat cells)
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Restore fat loss
Chondrocytes (cartilage cells)
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Repair of cartilage after injuries or other degenerative diseases such as Osteoarthritis
Dermal tissue (skin cells)
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Assistance in Plastic Surgery applications

  • Mesenchymal stem cells help repair hearts damaged by heart attack -- in part by becoming heart cells themselves.
  • Autologous Mesenchymal Stem Cell Therapy Delays the Progression of Neurological Deficits in Patients With Multiple System Atrophy -May 2008
  • Mesenchymal Stem Cell Transplantation Accelerates Hearing Recovery through the Repair of Injured Cochlear Fibrocytes
  • Mesenchymal stem cells have shown to have a Therapeutic potential of in prostate cancer bone metastasis –
  • Clinical applications of human Mesenchymal Stem Cells are evolving rapidly with the aim to improve hematopoietic engraftment, expanding HSC, preventing graft-versus-host disease (GVHD), correcting inborn metabolic errors and delivering a variety of therapeutic genes into the cells.

Applications of mesenchymal stem cells in tissue engineering and regenerative medicine
Mesenchymal stem cells have been used to regenerate marrow microenvironment after myeloablative therapy.
The use of natural and synthetic biomaterials as carriers for mesenchymal stem cells delivery has shown increasing promise for orthopedic therapeutic applications, especially bone formation. Mesenchymal stem cells are ideal for treating arthritis and connective tissue ailments. When introduced into the infarcted heart, mesenchymal stem cells prevent deleterious remodeling and improve recovery. Number of reports have also indicated that these cells possess the capacity to trans-differentiate into epithelial cells and lineages derived from the neuro-ectoderm, and in addition, mesenchymal stem cells can migrate to the sites of injury, inflammation and to tumors. These properties of mesenchymal stem cells make them promising candidates for use in regenerative medicine and may also serve as efficient delivery vehicles in site-specific therapy.
Future Research on Mesenchymal Stem Cells
According to American Diabetes Association, mesenchymal stem cells can be the key to healing diabetic foot ulcers: Diabetic foot ulcers are the primary cause of hospital admissions for diabetics. Foot ulcers that heal improperly are at risk for infection, which can lead to amputation

Wednesday, September 12, 2012

Congenital Epulis ( Gingival granular cell tumour ) of the Newborn

CONGENITAL EPULIS OF THE NEWBORN

Epulis is a rare tumor of the newborn, also known as granular cell tumor of the newborn or Neumann's tumor. This tumor arises from the mucosa of the gingiva, most commonly from the anterior part of the maxillary alveolar ridge, and is typically seen as a mass protruding out of the newborn child's mouth, which may interfere with respiration or feeding. Epulis is seen only in the newborn and is a different entity from other granular cell tumors. The tumor has a marked female preponderance of 8:1. The recommended treatment is prompt surgical resection. Recurrences of the tumor and damage to future dentition have not been reported, suggesting that radical excision is not warranted.
A newborn female with such a mass is described. The tumor was resected using a carbon dioxide laser; the postoperative course was uneventful. On histologic examination, it was composed of diffuse sheets and clusters of polygonal cells containing small round to oval nuclei and abundant coarsely granular cytoplasm. The tumor cells stained positive for vimentin, and negative for S100-protein, actin, desmin, laminin, keratin, estrogen, and progesterone receptors. Electron microscopic examination showed granular cells containing heterogeneous electron-dense granules, lysosomes, and cytoplasmic lipid droplets. The clinical and microscopic features of such tumors are reviewed. 
                                    Epulis, or congenital granular cell tumor (GCT), is a rare tumor of the newborn. It is seen as a mass arising in the mouth from the alveolar ridge; this mass may interfere with respiration or feeding. A case of congenital epulis is reported; the tumor was resected using a carbon dioxide laser. The clinical aspects as well as the morphologic, histologic, and electron microscopic features of this lesion and its treatment are reviewed. 
Although the clinical presence of the congenital epulis may frigten parents,it ceases to grow following birth and is entirely benign,with some cases undergoing spontaneous involution.The usual treatement is simple surgical excision,with care taken not to interfere with the developing dentition.There is no propensity for recurrence , even in those in which the lesion is incompletely removed.


Ref: Dentistry for child and adolescent .

Wednesday, September 5, 2012

Desmoplastic ameloblastoma of Maxilla

Ameloblastoma, a relatively common epithelial odontogenic tumor includes several histopathologic subtypes like follicular, plexiform, acanthomatous and desmoplastic variants. Hybrid desmoplastic ameloblastoma (DA) composed of typical desmoplastic ameloblastoma along with areas of follicular/plexiform ameloblastoma is an extremely rare variant of ameloblastoma.

       Desmoplastic ameloblastoma (DA) was first
described in detail by Eversole et al in 1984 and
is defined as “a variant of ameloblastoma with
specific clinical, imaging and histological                   
features” in the recent WHO classification of
odontogenic tumors. Thus, it often occurs in the
anterior region of jaws, presents with unique
radiographic appearance resembling fibrosseous
lesions and show distinct histopathology
characterized by extensive stromal
collagenisation or desmoplasia surrounding
compressed islands of odontogenic epithelium
making it a distinct entity.



Ameloblastoma is a rare odontogenic tumor accounting for around 1% of all the cysts and tumors in the jaws.It encompasses several histological variants like follicular, plexiform,basaloid,acanthomatous and desmoplastic variants.The striking difference in the anatomic location i.e. occurrence in the anterior-premolar region ofmaxilla/mandible, unusual radiologic presentation of mixed radiolucency-radiopacities with illdefined borders and distinctive histopathology of extensive stromal desmoplasia with scattered odontogenic epithelium makes it a distinct clinicopathologic entity. Additional findings
reported for DA are almost equal sex predilection and relative higher frequency of occurrence in
Asians.







A: Intraoral clinical photograph of the tumor in the
left maxilla. B, PNS view demonstrating a mixed
radiolucent and radiopaque appearance with opacification of
the sinus. Computed tomography scan demonstrating a mixed
radiolucent –radiopaque lesion (C). Cut surface of the gross
specimen demonstrating a solid, granular, creamish white
lesion (D). E: Radiograph of the gross specimen depicting a
mottled appearance with focal radiolucencies.

For further reference :
Source : http://www.easternjmed.org/PDF/2011_1/9.pdf

Indian doctor becomes WHO’s Deputy Director General

The World Health Organization has an Indian doctor for its new Deputy Director General for Programmes. Dr. Soumya Swaminathan, the directo...