Diagnostic procedures


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Diagnostic procedures

  1. 1. DIAGNOSTIC PROCEDURES Introduction Correct treatment begins with a correct diagnosis. Arriving at a right diagnosis requires knowledge, skill and art. • The dictionary defines diagnosis as “the art of identifying a disease from its signs and symptoms. • Symptoms are units of information sought in clinical diagnosis.  Symptoms are defined as phenomena / signs of a departure from the normal and indicative of illness. Symptoms can be classified accordingly: • Subjective symptoms: are those experienced and reported to the clinician by the patient. • Objective symptoms: are those ascertained by the clinician through various tests. Many diseases have similar symptoms. Hence the clinician must be astute in determining the correct diagnosis. Differential Diagnosis:  This technique distinguishes one disease from several other similar disorders by identifying their differences. 1
  2. 2.  Diagnosis by exclusion on the other hand, eliminates all possible diseases under consideration, until one remaining disease correctly explains the patients symptoms. Thus the criteria for on accurate clinical diagnosis includes:  a good case history  a thorough clinical examination  relevant investigations / diagnostic tests Medical History:  Even though there are virtually no systemic contraindicatios to endodontic therapy (except uncontrolled diabetes or a very recent myocardial infarction), a recent and succinct, comprehensive medical history is mandatory.  It is only with such a history that the clinician can determine whether medical consultation or premedication is required before diagnostic examination or clinical treatment is undertaken.  Some patients require antibiotic prophylaxis before clinical examination because, of systemic conditions like:  Heart value replacement  A history of rheumatic fever  Advanced AIDS 2
  3. 3.  In case of patients who daily take anticoagulant medication may need to have the dose reduced or dosing suspended, especially in case of a periodontal examination.  When patients report being infected with communicable diseases such as AIDS, tuberculosis, Hepatitis B, dentists and staff must use protective barriers.  The clinician must also know what drugs the patient is taking so that adverse drug reactions can be avoided.  Patients who present with mental or emotional disorders are not uncommon. In these cases too, medical consultation before the diagnostic examination would be in the best interests of the patient, Doctor and Staff. Dental History: After completing, the medical history, the clinician should develop the dental history.  The purpose of a dental history is to create a record of the chief complaint, the signs and symptoms the patient reports, when the problem began and what the patient can discern that improves / worsens the condition.  The most effective way for the clinician to gather this important information is to ask the patient pertinent questions regarding the chief complaint and listen carefully and sensitively to the patient responses.  Because dental pain frequently is the result of a diseased pulp, it is one of the most common complaints. 3
  4. 4.  Whatever the reason, the patients chief complaint is the best starting point for a correct diagnosis. Subjective Symptom: As mentioned before PAIN is a subjective symptom.  Judicious questioning of the pain can aid the diagnostician in developing a tentative diagnosis quickly. One should ask the patient the following:  the kind / type of pain  Location of the pain  Duration of the pain  What causes the pain  What alleviates it  Whether it is referred to another site or not Type / Kind of pain: Generally pulpal pain is described by the patient in one of the 2 ways. (a) Sharp, piercing and lancinating – due to the excition of the “A-delta” nerve fibres (myelinated principal sensory fibres) in the pulp. This pain may reflect on a reversible state of pulpitis. (b) Dull, boring, growing and excruciating pain: due to excitation and shower rate of transmission of the “C” nerve fibres (unmyelinated fibres).  This pain usually reflects on IRREVERSIBLE STATE OF PULPITIS. 4
  5. 5. Duration of pain:  At times pulpal pain lasts only as long as an irritant is present.  At other times, it lasts for minutes to hours.  In case of Acute reversible pulpitis.  Pain – short duration – disappears soon after removal of the stimulus.  Sharp, lancinating and piercing  Usually localized  Is more responsive to cold than to heat.  In case of irreversible pulpitis,  Pain – persists even after removal of the stimulus or irritant.  Diffuse.  Longer duration.  Responds abnormally to heat than to cold. Localization of pain: Pain is localized when the patient can point to spot a specific tooth or site with assurance and speed when asked to do so.  Usually short, piercing, lancinating pain is easy to localize and responds promptly to cold. 5
  6. 6.  When the pain is diffuse, it relates to a dental pain that is dull, boring and gnawing.  This pain can also be referred to other sites. Referred pain: At times pain is referred to other areas and even beyond the mouth.  Most commonly it is manifested in other teeth in the same or the opposing quadrant.  However, referred pain is not necessarily limited to the other teeth. It may, for eg. be ipsilaterally referred to the preauricular area, or down the neck or up the temporal area.  In these instances the source of extraorally refereed pain almost invariably is a posterior tooth. Patients may report that their dental pain is exacerbated by lying down or bending over.  This occurs because of the increase in blood pressure to the head, which increases the pressure on the confined pulp.  Abnormal dental pain caused by heat usually requires endodontic treatment.  Pain that occurs on changing the position of the head, awakens the patient from sleep, or occurs during mastication of food in a cariously exposed tooth usually indicates a need for treatment. Acute Reversible Pulpitis Irreversible Pulpitis 6
  7. 7. Pain:  Sharp, laminating, piercing.  Short duration – disappears soon after removal of the stimulus.  More responsive to cold.  Usually localized.  Dull, boring, growing excruciating pain longer duration.  Persists even after removal of the stimulus / irritant.  Responds abnormally to heat them to cold.  Diffuse. Objective Symptoms: Objective symptoms are determined by tests and observations performed by the clinician. These tests are as follows: Commonly used tests 1. Visual and tactile inspection 2. Percussion 3. Palpation 4. Mobility and depressibility 5. Radiographs 6. Thermal tests 7. Electric pulp test 8. Periodontal examination 9. Test cavity 10. Anesthesia test 11. Occlusal pressure test 7
  8. 8. 12. Gutta-percha point tracing 13. Transillumination 14. Staining Special Methods: 1. Xero – radiography 2. Pulse – oximetry 3. Laser – Doppler flowmetry 4. Computerized Tomography 5. Digital subtraction radiography 6. M.R.I. 7. R.V.G. 8. Computerized expert system 1. Visual and Tectile Inspection: This is one of the most simplest clinical tests.  Too often, it is done only causally during examination, and as a result, much essential information is lost inadvertently.  A thorough visual, tactile examination relies on checking the “3Cs” - Colour, Contour, Consistency. In case of soft tissues: such as gingiva – any deviation from the healthy, pink colour is readily recognized when inflammation is present. Contour: a change in contour occurs when there is swelling. 8
  9. 9. Consistency: a change in consistency from normal, healthy firm tissue to that of a soft, fluctuant or spongy tissue indicates a pathologic condition. In case of Hard tissues: even the hard tissues i.e. the teeth should be visually examined using the “3 Cs”. Colour: a normal appearing crown has a lifelike translucency and sparkle that is missing in pulpless teeth. • Teeth that are discoloured, opaque and less lifelike in appearance should be carefully evaluated. Because the pulp may already be inflammed, degenerated or necrotic. • Not all the discoloured teeth will require endodontic treatment.  Staining maybe caused by old amalgam restorations, root canal filling materials and medicaments, or systemic medication, such as tetracycline staining.  Many discolourations, however, are the result of disease commonly associated with nectrotic and gangrenous pulps, internal or external resorption, carious exposure. Contour: crown contours should be examined. Causes for changes in the crown contour could be:  Fractures  Wear facets  Restorations 9
  10. 10.  The clinician should be prepared to evaluate the possible effects of such changes on the pulp. Consistency: of the hard tissue relates to the presence of caries and internal or external resorption. Technique: the technique of visual and tactile examination is simple.  It can be done with one’s fingers, an explorer and the periodontal probe.  The patients teeth and periodontium should be examined in good light under dry conditions. For Example: a sinus tract (fistula) might escape detection if it is covered by saliva or an interproximal cavity may escape notice if it is filled with food.  Loss of translucency, slight colour changes and cracks may not be apparent in poor light (in such cases, a trasilluminator may aid in detecting enamel Cracks / Crown #s)  Visual examination should also include the soft tissues adjacent to the involved tooth, for detection of swelling.  The crown of the tooth should be carefully evaluated, to determine whether it can be restored properly after completion of endodontic treatment.  Finally, a rapid survey of the entire mouth should be made, to ascertain whether the tooth requiring treatment is a strategic tooth. 3. Percussion: 10
  11. 11.  In percussion, the crown of a tooth is tapped with the tip of a finger or with an instrument.  A painful response to percussion denotes inflammation of the periodontal membrane.  Although percussion is a simple method of testing, it may be misleading if used alone.  In performing the test, several teeth are percussed in a random order, to eliminate bias on the part of the patient.  Initially a suspect tooth should be tapped very gently, since the periodontal membrane maybe extremely tender. If there is no response a sharp tap is given.  One should change the direction of the blow from the vertical occlusal to the buccal or lingual surfaces of the crown and strike separate cusps in a different order.  It must be born in mind that tenderness to percussion does not necessarily denote pulpal disease.  A tooth with a healthy pulp may develop on acute apical periodontitis from a blow or premature occlusal contact. or an acute periodontitis maybe the sequel to food packing between two teeth. The absence of a response to percussion is quite possible when there is chronic periapical inflammation. 11
  12. 12. If a metallic instrument is used, the sound produced by percussing a tooth with periapical disease is sometimes obviously duller than that given by a tooth with an intact periapex. 4. Palpation: in this simple test, light pressure is applied with the fingertip, to examine tissue consistency and pain response. • Although simple, it is an important test • Its value lies in locating the swelling over an involved tooth and determining the following: i. whether the tissue is fluctuant and enlarged sufficiently for incision and drainage. ii. the presence, intensity and location of pain iii. the presence and location of adenopathy iv. the presence of bone crepitus. When palpation is used to determine adenopathy, it is advisable to exercise caution when palpating the lymph nodes, in the presence of an acute infection, to avoid the possible spread of infection through the lymphatic vessels. Diagnostically:  When posterior teeth are infected, the submaxillary lymph modes become involved.  When anterior teeth are involved, the submental lymph nodes become involved. 12
  13. 13. Tenderness over the root apex of a tooth indicates inflammation of the periodontal membrane. But this can also result from other causes other than pulpal diseases.  Excluding absess formation associated with periodontal disease, swelling of the mucosa over the root apex of a tooth denotes partial or complete necrosis of the pulp.  When the infection is confined to the pulp and has not progressed into the periodontium, palpation is not diagnostic.  Palpation, percussion, mobility and depressibility test the integrity of the attachment apparatus i.e. the periodontal ligament and bone, and are not diagnostic when the disease is confined within the pulpcavity of a tooth.  In short, palpation, mobility and depressibility are tests of the periodontium rather than of the pulp. 5. Mobility – Depressibility testing: The mobility test is used evaluate the integrity of the attachment apparatus surrounding the tooth.  The test consists of moving a tooth laterally in its sockets by using the fingers or preferably, the handles of two instruments.  The objective of this is to determine whether the tooth is firmly/ loosely attached to its alveolus. 13
  14. 14.  The amount of movement is indicative of the condition of the periodontium. The greater the movement, the poorer the periodontal status. Similarly, the test depressibility consists of moving a tooth vertically in its socket.  This test may be done with the fingers or with an instrument.  When depressibility exists, the chance of retaining the tooth ranges from poor to hopeless. Classification of mobility: (According to Grossman) i) First degree mobility: is barely discernible movement. ii) Second degree mobility: is a horizontal movement of 1 mm or less. iii) Third degree: is a horizontal movement of greater than 1mm, often accompanied by a vertical component of mobility. The pressure exerted by the purulent exudates of an acute apical abcess may cause some mobility of a tooth. In this situation the tooth may quickly stabilize after drainage is established and occlusion is adusted. Additional causes for tooth mobility: 1. Advanced periodontal disease. 2. Horizontal root fracture in the middle and coronal third. 3. Chronic bruxism / clenching. Note on Mobilometers: 14
  15. 15. These are electronic devices / gadgets which aid in determining tooth mobility. The apparatus essentially consists of two electrodes or prongs which hold the facial and lingual surface of the teeth. The degree of mobility tested is then reflected as a numerical reading either on the instrument itself or on an attached computer screen. Radiographs: The radiograph is one of the most important clinical tools in making a diagnosis.  But some clinicians rely exclusively on radiographs to arrive at a diagnosis which can lead to major errors in diagnosis and treatment. Because the radiograph is a two dimensional image of a 3-dimensional object, misinterpretation is a constant risk.  To use radiographs properly, the clinician must have the knowledge and skill necessary to interpret them correctly.  A thorough understanding is required of the underlying normal or anomalous anatomy and the changes that can occur due to aging trauma, disease and healing.  It is important that radiographs be of excellent quality.  To produce an excellent radiograph one must master the necessary skills: 1. Proper placement of the film in the patient’s mouth. 15
  16. 16. 2. Correct angulation of the cone in relation to the film and oral structures (to prevent distortion of the anatomic images). 3. Correct exposure time – so the images are recorded with identifiable contrasts. 4. Proper developing technique. Radiographs can contain information on: 1. Presence of caries that may involve or may threaten to involve the pulp. 2. The number course, shape, length and width of the root canals. 3. the presence of calcified material in the pulp chamber or root canal. 4. the resorption of dentin originating within the root canal internal resorption or from the root surface (external resorption). 5. Calcification or obliteration of the pulp cavity. 6. Thickening of the periodontal ligament. 7. Resorption of cementum. 8. Nature and Extent of periapical and alveolar bone destruction. 9. Root Fracture. When posterior teeth are being investigated, a bite wing film provides an excellent supplement for finding the extent of carious destuction, the depths of restoration, the presence of pulp caps or pulpotomies and dens evaginatus or invaginatus. 16
  17. 17. Root fractures: These could be difficult to detect on a radio graph, especially vertical root fractures which can be identified only in advanced cases of root resorption. Horizontal fractures maybe confused radiographically with linear patterns of bone trabecule. The two can be differentiated by noting that the lines of bone trabeculae extend beyond the border of the root while root fractures often cause thickening of the periodontal ligament. 17
  18. 18. Difference between internal and external resorption: Differentiation between internal and external resorption maybe made radiographically: 1. The lesion of internal resorption usually has sharp smooth margins that can be clearly defined. However, it need not be symmetrical. 2. The pulp “disappears” into the lesion not extending through (i.e. the shadow of the pulp) the lesion in its regular shape. Radiographic misinterpretation: In some instances two or more exposures are necessary to check out detail from more than one horizontal angle. This is especially in the case of the mental foramen – this foramen maybe directly superimposed over the apex of the mandibular premolars for example.  The nasopalatine foramen also maybe superimposed on the apex of the maxillary central incisors.  These foramina are actually some distance from the apices of these teeth.  To find out whether it is a foramen or truly a periapical lesion one must change the horizontal angle of the cone of the x-ray machine to the mesial / distal during separate exposures.  If the radiolucent arc is actually a lesion associated with the periapex than its shadow will remain “attached” to the root end despite of a mesial or distal shift in separate films. 18
  19. 19. Lesions within the tooth observable by radiographs: a. Pulp death in a developing tooth is readily apparent because the root ceases to develop. b. Pulp stones, inflammation. c. Internal resorption seen following traumatic injury. Lesions outside the tooth observable on radiographs: Some of the most common occurrences seen radiographically on the out side of the root of the tooth are – a. Widening of periodontal space occurring due to  Acute apical periodontitis.  Acute apical abscess  Occlusal trauma. b. Changes associated with chronic periapical abscess. c. External root resorption. In case of external root resorption: lesion has ragged margins and shadow of the pulp “passes through” the lesion unaltered. RADIOGRAPH ANGULAR – PERIRADICULAR LESIONS Most often the following features are seen:  Widened periodontal ligament space  Inflammatory apical root resorption 19
  20. 20.  Most often associated with pulp necrosis and infection. Other conditions where one can notice a windened PDL space are:  Acute apical periodontitis  A beginning acute apical abscess  Acute pulpitis (occasionally) Radiographic changes as sequelae to pulp necrosis The commonly observed changes are: a) Chronic apical periodontitis – a well circumscribed osseous lesion  Radiolucent area varying in size from a few mms to a cm or larger in size  Border / bony perimeter maybe radiopaque.  Do not always occurs at the periapex / occasionally seen on the lateral surface of the root in association with an accessory canal. b) Chronic apical abscess:  Larger, more diffuse and irregular radiolucent lesion. c) Apical cyst: may develop from a chronic abscess. In this case lesion appears – more circumscribed, more like a “granuloma” in appearance. 20
  21. 21.  It also moves roots of teeth laterally. NATKIN has postulated that the larger the lesion the more apt it is to be a cyst. A number of pathologic changes in and near the alveolar process maybe mistaken for periradicular lesions of pulpal origin. They are: I. Lesions of non endodontic origin: 1. Globulomaxillary cyst – inverted pear shaped. 2. Midline palatal cyst – occurs in the midline. 3. Cyst of the nasopalatine canal or foramen – occurs mainly in the palatine process. II. Periodontal lesions: maybe mistaken for periradicular ones. ⇒ The periodontal probe and pulp tester are invaluable in determining the origin of the lesion. ⇒ Another method is to place a silver or gutta percha point in the periodontal pocket and take a radiograph. III.Cementoblastoma: common errors in diagnosis center around the lesions of cementoblastoma particularly during stage I when radiolucency is so apparent. (Once it begins to calcify into a selerotic lesion, little doubt should exist about the nature of the lesion). 7. Themal testing: 21
  22. 22. One of the most common symptoms associated with a symptomatic inflammed pulp is pain induced by hot or cold stimulation.  Hot and cold tests are valuable diagnostic aids. • According to Grossman, although both are tests of sensitivity they are dissimilar and are conducted for different diagnostic reasons. • A response to cold indicates a vital pulp, regardless of whether that pulp is normal and abnormal. • A heat test is not a test of pulp vitality. An abnormal response to heat usually indicates the presence of a pulpal or periapical disorder requiring endodontic treatment.  Another diagnostic difference pointed out by Grossman is that when a reaction to cold occurs the patient can quickly point out to the painful tooth.  Whereas in a heat test, the response could be localized or diffused or even referred to a different site. The results of the thermal test should be correlated with the results of other tests to ensure validity. Technique of performing thermal tests:  Before testing, the patient should be told what tests are going to be performed and why.  Additionally, the patient should be given some idea of what to expect. 22
  23. 23.  The tests should be first performed on teeth which are to be used as controls i.e. corresponding (if found) on the opposite side of the same arch. Contralateral teeth can also be used as controls.  By doing so, the patient gets an idea of how the tests will feel.  The dentist should also inform the patient how to respond when a sensation is experienced. For Eg: The patient should be instructed to raise a hand as soon as any sensation is felt. The heat or cold test (even EPT) tests are performed by placing the stimuli on: Anterior teeth: labial (enamel) surface of the incisal third of the crown. Posterior teeth: Occluso Buccal surface. However, placing the stimulus on exposed dentin should be avoided – because an accelerated or exagerrated response is likely. Also the stimulus should not be applied against restorations unless unavailable. Non-metallic restorations: Poor conductors tests gives a delayed response or no response Metallic-restorations: Good conductors  This can result in response at low levels of stimulation.  They may also cause misleading results by conducting the stimulus to an adjoining metallic restoration in another tooth. 23
  24. 24.  This effect can be reduced by placing a celluloid strip between the teeth.  The teeth in the quadrant must first be isolated and then dried with 2x2 inch guaze and a saliva ejector placed.  Cohen states that teeth should not be dried with a blast of air because  Room temperature air might cause shock.  Saliva might be sprayed on the clinician or the assistant. Heat Test: The heat test can be performed using different technique that deliver different degrees of temperature. ⇒ According to Cohen the preferred temperature is 65.5°C (150°F). But according to AHR Rowe et al in his article on Assessment of pulpal vitality (Int End Journal 1990 V-23) temperatures upto 150°C are necessary for conducting thermal tests on teeth which are first smeared with Vaseline to avoid g.p. sticking to tooth. Heat testing can be made with  Hot air blast  Hot water  Hot burnisher / any instrument which can deliver controlled temperature to the tooth  Hot Gutta-percha Where a gold crown is present, heat maybe applied by polishing the crown with an Abrasive disc. 24
  25. 25. When testing with gutta-percha, it is heated over an alcohol flame until it becomes shiny and sags, but before it begins to smoke. Care should be taken not to place an overheated gutta percha stick or prolonged application of the stick as it may cause a burn lesion in an otherwise normal pulp. A different technique is required for the application of hot water. Method:  Isolate with rubber dam  Tooth is immersed in “Coffee hot” water delivered from a syringe. (According to Cohen this is the best method for thermal testing teeth with porcelain or full metal coverage). Disadvantages: The response noted is limited to only the tooth which is tested. Cold Test: For the cold testing, the teeth must remain isolated and dry. The most common techniques for cold testing utilize, 1. A stream of cold air from a 3 way syringe directed against the crown of a previously dried tooth. 2. Ethyl chloride spray – it is sprayed liberally on a (evaporates rapidly by absorbing heat and cooling the tooth surface) cotton pellet and held against the middle 3rd of the facial surface. The ethyle chloride technique is effective even on teeth covered with cast metal crowns. 25
  26. 26. 3. Sticks of ice 4. Carbon dioxide snow in the form of dry ice pencil.  This produces lower intrapulpal temperatures than other methods (Aisberger and Peters 1981).  Is far more effective (Ehrmann, 1973).  Reliable even in immature teeth. Responses to thermal tests: The patients responses to heat and cold testing are identical because the neural fibres in the pulp transmit only the sensation of pain (Hydrodynamic theory – Brannstorm). There are four possible reactions the patient may have: 1. No response – pulp maybe non vital Or vital, but giving a false negative response because of  Excessive calcification  Immature apex  Recent trauma  Patient premedication 2. A mild to moderate transient thermal pain response.  This is usually considered normal. 3. A strong, painful response that subsides quickly after removal of the stimulus – this is characteristic of Reversible pulpitis. 26
  27. 27. 4. A strong, painful, response that lingers after the thermal stimulus is removed – this indicates a symptomatic irreversible pulpitis. Modification of technique for thermal tests:  A modified technique for the heat and cold thermal tests is provided by the analytical technique pulp tester which has a hot probe tip and a cold probe tip. The heating of the hot probe tip and cooling of the cold probe tip are controlled separately in the membrane switch on the control panel. 8. Electric Pulp Tests: The electric pulp tester is designed to stimulate a response by electrical excitation of the neural elements within the pulp. Historically, the EP tester has been used in dentistry since as early as 1867 and has evolved over the years into the present electronic digital pulp tester. It is a valuable tool for diagnosis because not only does it help the clinician in determining pulp vitality but with thermal and periodontal tests it can also aid in differentiating among radiographic signs of pulpal, periodontal or non odontogenic cause. • The EP test merely suggests whether the pulp is vital or non vital. • It does not provide any information about the health or integrity of the pulp. 27
  28. 28. • It does not provide any information about the vascular supply to the tooth, which is the real determinant of vitality. Technique: 1. Describe the test to the patient in a way that will reduce anxiety and will eliminate a biased response. To eliminate a biased decision EPT should first be performed on a normal healthy tooth (control), adjacent or contra lateral. This aids in determining the patients threshold level. 2. Isolate the area of teeth to be tested with cotton rolls and a saliva ejector and air dry all the teeth. 3. Check the electric pulp tester for function, and determine that current is passing through the electrode. 4. Apply an electrolyte (tooth paste) on the tooth electrode and place it against the dried enamel of the crowns’ occlusobuccal or inciso labial surface.  All restorations must be avoided because they may cause a false reading. 5. Retract the patients cheek away from the tooth electrode with the free hand. This hand contact with the patients cheek completes the electrical circuit. 6. Turn the Rheostat slowly to introduce minimal current into the tooth and increase the current slowly. 28
  29. 29.  Patients should be instructed to raise a hand as soon as they begin to feel slight tingling or sensation of heat.  Record the result according to the numeric scale on the pulp tester. Each tooth should be tested 2 or 3 times and the reading averaged. Reason: The patient’s response may vary slightly (which is common) or significantly (which suggests a false positive or negative the response). Factors - affecting level of Response: 1. Enamel thickness: Thicker the enamel, the more delayed the response. (Thin anterior teeth – respond faster, Broad posterior teeth – slower response – because of greater thickness of enamel and dentin). 2. Probe placement on the tooth. (Posterior teeth: occlusal third, anterior teeth: Incisal third – to avoid false stimulation of gingival tissue). 3. Dentin calcification 4. Interfering restorative materials. 5. The cross sectional area of the probe tip 6. patient level of anxiety. Advantages of E.P.T: 1. Intensity of stimulus is comfortable to the patients. 29
  30. 30. 2. The digital display of many E.P. Testors provides instant, easy and reliable information. 3. In some E.P. testers, a red indicator light flashes on and off when maximum stimulus is reached. 4. Gives a quantitative reading which can be compared with the normal reading of control tooth. Disadvantages of EPT: 1. It cannot be used on patients having cardiac pacemaker because of potential interference with the pacemaker. Studies by woolley and associated have shown that currents of the magnitude of 5 to 20 milliamps are sufficient to modify normal pacemaker function. 2. Usually cannot be used when gloves are worn. In order to stimulate the pulp nerve fibers, the electric current must complete a circuit. Hand contact with the patients cheek completes the circuit. With gloved hands that connection is interrupted. 3. Some E.P. Testers are very expensive. 4. EPT is not useful on recently erupted teeth with immature apex. Studies have shown that newly erupted teeth have more unmyelinated axons than do mature teeth the speculation being that some of these larger fibres may ultimately become myelinated. Since it is principally the pulpal A fibers that respond to electric pulp testing, variability in the number of ‘A’ 30
  31. 31. fibres entering the tooth offers a possible explanation to why electric pulp tests tend to be unrealiable in young teeth. 5. Recently traumatized teeth cannot be tested. 6. The probe tip of some EPT is removable and it falls out easily. 7. No indication is given regarding the state of vascular supply which would give a more reliable measure of the vitality of the pulp. 8. Readings from posterior teeth with partial vital pulps maybe misleading. (because in multirooted teeth one canal may have vital pulp tissue and other canals necrotic tissue). False Reading: As stated, the results from the EPT could be misleading and these could be grouped as: A) False positive response: means the pulp is necrotic but the patient nevertheless signals that he feels sensation. B) False negative response: means the pulp is vital but the patient appears unresponsive to electric pulp tests. Main reasons for a false positive response: 1. Conductor / Electrode contact with a larger metal restoration (bridge, class II restoration) or the gingiva allowing the current to reach the attachment apparatus. 2. Patient anxiety. 3. Liquifaction necrosis may conduct current to the attachment apparatus and the patient may slowly raise his/hand near the highest range. 31
  32. 32. 4. Failure to isolate and dry the teeth properly. Main reasons for a false – negative response: 1. Patient heavily premedicated with analgesics, narcotics, alcohol or tranquilizers. 2. Inadequate contact with the enamel. 3. Recently traumatized tooth. 4. Excessive calcification in the canal. 5. Dead batteries or forgetting to turn on the pulp tester. 6. Recently erupted tooth with an immature apex. 7. Partial necrosis (Although the pulp is still partially vital, electric pulp testing may indicate that it is totally necrotic). Types of pulp testers: Two types of electric pulp tester are available I. 1) Current is varied II. 1. Monopolar 2) Voltage is varied 2. Bipolar The former in which current is varied is considered preferable, since a given voltage may lead to different amounts of current due to variation in the electrical resistance of the tissues, especially enamel. The common commercially available testers are: 32
  33. 33. 1. Analytic technology pulp tester: Here the wave form has an output in the form of bursts of ten high frequency pulses followed by a space.  This is done to minimize patient discomfort.  The EPT is turned on automatically when the probe touches the tooth and is turned off when the tooth contact is broken (after a delay of 15 secs).  There is a digital display and the only control on the EPT is the rate of increase of the stimulus.  To complete circuit patient may touch metal handle. 2. Digilog pulp tester 3. Green wood pulp tester 4. Pelton crane pulp tester 5. Parkell pulp tester (battery operated) Periodontal Examination: No dental examination is complete without careful evaluation of the teeth’s periodontal support.  The periodontal probe should be an integral part of all endodontic tray set ups.  Using a periodontal probe, the clinician examines the gingival sulcus and records the depths of all pockets. 33
  34. 34.  Multirooted teeth are carefully probed to determine whether there is any furcation involvement.  A lateral canal exposed to the oral cavity by periodontal disease may become the portal of entry for toxins that cause pulpal degeneration.  To distinguish lesion of periodontal origin from those of pulpal origin, thermal and electric pulp tests, along with periodontal examination are essential. 9. Test Cavity: This method is performed when other diagnostic methods have failed.  It involves the slow removal of enamel and dentin to determine pulp vitality.  Without anesthesia and using a small round bur, the dentist removes the dentin with a revolving high speed bur aimed directly at the pulp.  If the pulp is vital, the patient will experience a quick sharp, pain at or shortly beyond the dentin enamel junction.  A sedative cement can then be placed in the prepared cavity and the search for the cause of pain may be continued.  On the contrary, if no pain / sensitivity is recorded, the cavity preparation maybe continued until the pulp chamber is reached and if the pulp is noticed to be necrotic, routine endodontic treatment could be performed. 34
  35. 35. 10. Anesthesia test:  In the uncommon circumstance of diffuse strong pain of vague origin, when all other tests have failed, the Anesthesia test is performed.  Objective: To anesthetize a single tooth at a time until the pain disappears and is localized to a specefic tooth. Technique: Using either infiltration or the intraligament injection, inject the most posterior tooth in the area suspected of being the cause of pain.  If pain persists, when the tooth has been fully anesthetized, anesthetize, the next tooth mesial to it and continue to do so until the pain disappears.  If the source of pain cannot be determined whether in maxillary or mandibular teeth, an inferior alveolar (mandibular block) infection should be given.  Cessation of pain naturally indicates involvement of a mandibular tooth, and localization of the specefic tooth is done by the intraligament injection, when the anesthetic has spent itself.  This test is obviously a last resort and has an advantage over the “Test cavity”, during which iatrogenic damage is possible. 11.Occlusal pressure or Biting test: A frequent patient complaint is pain on biting or chewing. Causes for such symptoms: - Apical periodontitis, - Apical abscess 35
  36. 36. - Incomplete tooth fractures  A clinical test that simulates the chief complaint is the occlusal pressure test or biting test. Method: Several methods exist like biting on:  Orangewood stick  Burlew rubber disc  Wet cotton roll  The oragnewood stick and Burlew rubber disc allow pinpoint testing of individual cusp area.  The wet cotton roll has the advantage of adapting to the occlusal surface allowing for pressure over the entire occlusal table.  An interesting clinical observation in patients with tooth infarctions (“Cracked Tooth Syndrome”) is pain often experienced when biting force is released rather than during the downward chewing motion. 12. Gutta-Percha Point Tracing: Technique: Place a gutta percha point through the sinus / fistulous tract and take a radiograph.  This can localize endodontic lesion to the specific tooth.  In addition, this test aids in the differential diagnosis between a periodontal and an endodontic lesion. 13. Transillumination & Magnification: 36
  37. 37.  Fiberoptic lighting and chairside magnification have become indispensable in the search for cracks, fractures and unfound canals and obstructions in root canal therapy.  The fact that magnification (e.g. microscopes) and trasillumination might allow the dentist the only means of diagnosing an offending cracked tooth is becoming an increasing reality. 14. Staining: The purpose of a staining test is isolation of a cracked tooth. Technique: there are 3 methods to stain a tooth. 1. Remove the filling from the suspected tooth and place 2% Iodine in the cavity preparation. The iodine stains the fracture line fracture lines can be identified with food colouring placed on the dried occlusal surface.  The dye solution stains the fracture line.  The occlusal surface is cleaned with a cotton pellet lightly moistened with 70% isopropyl alcohol.  The alcohol washes away the food coloring on the surface, but the colouring within the fracture line remains and becomes apparent 2. Mix a dye in zinc oxide eugenol cement and place it in the cavity preparation after filling has been removed. The dye will seep out and line the fracture. 3. Have patient chew a disclosing tablet after taking out the filling of the fractured tooth. The fracture line will be stained. SPECIAL METHODS 37
  38. 38. 1. Xeroradiography: Xeroradiography is an imaging technique that has been proposed as an alternative to conventional x-ray film radiography. The term xero-radiography is derived from the greek word “xeros” which means “dry”. Technique: The x-ray image is recorded on a photo-conductive selenium coated plate rather than x-ray film. Before use, the selenium plate is given a uniform electrostatic charge, placed in a light proof plastic cassette, positioned in the mouth, exposed to x- ray.  The processed image is transferred onto clear adhesive tape and fixed on to an opaque plastic base.  The resulting image maybe viewed either as a photograph with reflected light or as a radiograph with transmitted light from a view box. Advantages: 1. The radiation exposure is 1/3rd that of the conventional x-ray film. 2. Better edge enhancement and image quality. 3. Xeroradiographs have inherently wide latitude. i.e. it is possible to image objects having a broad range of densities in a single exposure.  Wide latitude also means the acceptable images can be obtained over a relatively broad range exposure conditions. 38
  39. 39. Advantage is – it can dramatically reduce the number of exposures that have to be repeated because of technical inadequacies.  The height of alveolar crest is often well demonstrated, aiding in diagnosis of periodontal disease.  Caries maybe seen readily. 4. It produces permanent dry image for viewing in about 20 seconds. 5. The plates maybe reconditioned, recharged and used repeatedly. 39
  40. 40. 2. Pulse Oximetry:  Tests relying on the passage of light through a tooth have been considered as a possible means of detecting pulp vitality with greater objectivity.  The pulse oximeter is a non-invasive O2 saturation monitor that provides continuous pulse rate readings.  The liquid crystal display (LCD) gives oxygen saturation, pulse rate and plethysmpographic wave form readings. Concept: Pulse oximetry uses red and infrared wave length in order to transilluminate a tissue bed and detects absorbance peaks due to pulsative circulation.  This information is used to calculate the pulse rate and oxygen saturation.  The tooth to be tested is sandwiched between a photoelectric detector and red and infrared light emitting diodes. This method is clearly superior to other vitality tests since it does not rely upon sensory nerve response. (Other routine methods rely on stimulation of a-delta nerve fibres for assessment of pulp vitality). 40
  41. 41. 3. Laser Doppler Flowmetry: Due to the biased, false –ve and positive responses elicited through the EPT the need for a better and more reliable method for determining pulp vitality arose.  A method which determined and registered the blood flow rather than the neural response was preferred. LDF was thus introduced first in 1972 to determine blood flow in Retina of Rabbits – RIVA, Ross and Benedek as a non-invasine method to measure blood flow.  The crux of the LDF is based on the detection of movement of blood cells in the pulpal blood vessels, with thus gives a true picture regarding pulp vitality. Technique: essentially consists of a laser light i.e., helium neon laser at 632.8nm.  It is focused on the tissue under study with a fiber optic probe.  As the light hits the various components of the tissues, it is partially absorbed and partially back scattered. The back scattered light has 2 components: i) Light back-scattered from the static tissues which has the same frequency as the light going on. ii) The other component is the Doppler shifted light with a different frequency. 41
  42. 42. The back scattered light is processed and an ouput signal is produced i.e. both the unshifted an shifted light is transmitted to a detector by optical fibres where it is charged into an electric current and processed. The detected output signal can be fed onto an analog printer, or be rand from a digital board. Advantages of LDF: 1. Non-invasive. 2. Simple to apply. 3. Provides a continuous record. 4. Useful to demonstrate establishment of vitality of untreated teeth. Disadvantages: 1. Impossible to calibrate the readings in absolute units. 2. Output may not be linearly related to blood flow. 4. Computerized Tomography: Computed tomography was introduced in the mid 1970’s.  Computed tomographic systems are also referred to as computed axial tomography scanners (CAT).  CT scanners produce digital data measuring the extent of x-ray transmission through an object.  This numerical information maybe transformed into a density scale and used to generate or reconstruct a visual image. Tachibana, has reported about the use of x-ray CT in endodontics. 42
  43. 43.  It is possible to determine the bucco-lingual and mesio-distal widths of teeth and the presence or absence of root canal filling materials and metal posts.  Also observable are the carious lesions, extension of the maxillary sinus and its proximity to the root apices. Advantages: 1. Observation of structures which are difficult to visualize with conventional x-rays. 2. Provides images for 3-dimensional image of roots, root canals and teeth. Disadvantages: 1. Expensive 2. Skin dose is large 3. Time consuming. 5. Digital subtraction radiography: The progress of caries from an incipient lesion, the DEJ is often difficult to detect.  Likewise, the assessment of healing or expansion of the periapical lesion after root canal therapy is a challenge therefore the subtle changes in the density of the lesions maynot be detectable with the naked eye.  Subtraction radiography offers a remedy for these problems. 43
  44. 44.  It is an image enhancement method. Here, the area under focus is clearly displayed against a neutral gray black background or it is superimposed on the radiograph itself (i.e. the required areas are enlarged against the entire background).  This DSR maybe used to assess the successfulness of RCT and also periapical lesions. 6. Radiovisuography: RVG digitizes ionizing radiation and provides an instantaneous image on a video monitor, thereby reducing radiation exposure by 80%. The RVG has 3 components: 1. Radio component: consists of an hypersensitive intra oral sensor and a conventional x-ray unit. 2. “Visio” portion: consists of a video monitor and a display processing unit. 3. “Graphy” portion: is a high resolution video printer that provides an instant hard copy of the screen image using the same video signal. Advantages: 1. Elimination of X-ray film 2. Significant reduction in exposure time. 3. Instantaneous image display The RVG system appears promising for the future of endodontics. 44
  45. 45. But, the resolution of RVG is slightly lower than that produced with conventional film, which can however be improved through enhancement procedures. 7. Computerized expert system: Reported by John Firrola, the CES Viz, Comendex was used for the diagnosis of selected pulpal pathosis i.e.  Normal pulp  Reversible pulpitis.  Irreversible pulpitis (due to hyperocclusion).  Necrotic pulp  Infection due to endodontic failure. Appropriate diagnostic case facts are obtained and this data is entered into the computer. The computer checks and gives out the diagnosis. - With rapid advances being made in the field of computers one can expect more efficient programmes for endodontic diagnosis. Conclusion: To conclude, I would like to say that one cannot depend solely on these tests to arrive at a diagnosis. - As mentioned before, the clinicians knowledge, skill and art combined with these diagnostic tests will help one to make the right diagnosis. 45
  46. 46. 46