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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 : 
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 .

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. 

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