5: Diagnosis of endodontic problems

Diagnosis of endodontic problems

The nature of endodontic diagnosis

Diagnosis is the art of systematic use of verified or unverified information to derive the identity or cause of a problem; it involves objective and intuitive processes. The clinician will often call upon objective processes but also (sometimes unknowingly) relies heavily on intuitive processes. Intuition is an inner faculty not well defined by scientific disciplines but is well recognized in other areas of knowledge. The best example of its power is given by the ability of the patient to intuit a cause without any scientific grounding in the problem. Such a process alone is not sufficient for a clinician but supplements objective, learnt processes. Diagnosis has been defined in a variety of ways (Table 4.1). It is one of the more intellectually stimulating parts of clinical practice, which brings out the detective zeal in the clinician.

The process of diagnosis is a complex one, involving several diverse aspects. The identification of a disease is based on knowledge of its pathology, natural history and its presenting features (Table 4.2).

The presentation of any disease is subject to normal variation, which may be depicted by its Gaussian distribution, classically described as a bell curve (Fig. 4.1).

The variations are a function of genetically expressed biological differences between patients and the anatomical conjunction within which the disease manifests. Dentists are normally taught the “central tendency”, that is, the commonest presentation; it being too difficult and complicated to teach each of the variations that may present in reality. A practical clinical interpretation to augment this theoretical knowledge is, therefore necessary and is acquired through supervised clinical practice, where a teacher shows the links between clinical manifestations and the embedded theoretical picture of histopathology and physiology. Subsequent independent practice upon graduation requires vigilant tracking of the outcome of all diagnostic decisions; that is, did their judgement solve the patient’s problem. The problem of coincidental resolutions can only be overcome through dedicated, conscientious, active, repeat experience, which allows a definitive pattern of outcomes to be consolidated. The dentist, thus through a process of mind application and intuition learns to recognize when their decision was correct and when the favourable outcome may simply have been a coincidence. It stands to reason that a peripatetic dentist who does not work for long in any one place is unlikely to develop such integration and consolidation of diagnostic insight (see Table 4.2). Through the gathering of such experience, the use of basic pathological principles, together with the aid of intuitive processes, the dentist is able to develop the ability to recognize the “outliers” that present at the extremes of the Gaussian distribution. To reach such a status requires considerable active experience.

In the interests of efficiency, experienced dentists may learn to apply a heuristic approach, whereby they reduce the identification of a problem to certain key or pathognomonic features (Table 4.3). This can work if applied with due diligence and caution but is a trap for misdiagnosis if applied without a proper foundation.

Clinical diagnosis is predicated upon the systematic gathering of information, first through a dialogue with the patient to determine their perspective on the problem, and second through a process of observation. The ability/skill to gather accurate information through interview and interrogation is an art mastered through experience. Although received wisdom suggests that patients should be allowed to convey their problems in their own way and words, experienced diagnosticians will firmly iterate that histories are taken not given.

Information gathering continues with the examination, which is a combination of direct observation to detect signs of variations from the normal, manipulation of various afflicted parts with the aim of determining texture, shape, mobility, response and, finally, stimulation to elicit the reported symptoms. Each of these must be performed with clear insight of the outcome sought and potential confounders inherent in the process.

The gathered information is integrated into an overall picture, which requires the ability/skill to extrapolate and interpret presenting features based on knowledge of the disease process and its possible unusual presentations. This process is actually nothing more than pattern recognition, which has become a science and discipline in its own right.

The implication of this is that the process of assimilation of information and pattern comparison may begin early in the diagnostic pathway, the clinician need not wait for all the information to be gathered before forming an opinion of the likely outcome. This may be viewed as biased thinking in some quarters but is in actual fact merely recognition of how our brain functions. Active but cautious adoption of the principle enables the history to be garnered efficiently and effectively by virtue of the fact that the clinician will be able to intuit those aspects that require confirmation and those aspects that require rejection. That is, it allows the clinician to take rather than be given the history. Similarly, the process of examination is directed towards confirmation of that which is expected (positive or negative), according to the preliminary diagnosis. Lack of confirmation should signal that the problem may either be an outlier, or that a different conclusion may hold true. Some clinicians may argue that such an approach may lead to the missing of vital signs. This is not actually so, particularly if the clinician is conscientious in their search. The mind must, by definition, be open to all possibilities at the same time. The ability to “see” is critical; this is not merely related to good eyesight and conditions for vision but, more importantly, to the existence of the relevant “recognition information” in the “mind’s eye”. That is, the mind must first be prepared thoroughly to “see” by visualization of assimilated theoretical knowledge, which is tempered and integrated through active (with mind switched on) clinical experience.

The nature of endodontic problems

The clinician will be examining the patient for a relatively small variety of disorders in an endodontic assessment, yet the process seems complex and confounds many dentists. The prime reason for this is that there is considerable overlap in the presenting descriptions of various conditions and it remains for the discerning clinician to tease out subtle discriminating differences. In many cases, the patient seeks treatment because of overt signs and symptoms, some of which have an obvious diagnosis, but many conditions are silent (sign and symptom-free) and discovered only by chance on routine examination. Common disorders, which may be revealed during an endodontic assessment are given in Table 4.4.

Patient assessment

At the first appointment, the dentist must assess and characterize the patient, their dental problem and treatment need before actually embarking on any treatment, since numerous factors affect management and treatment choice. This process of assessment requires an “intimate and open” interaction between dentist and patient, which by definition, must therefore be mutually consented.

The nature of presenting complaints

The nature of primary presenting complaints from endodontic patients is diverse and can embrace pain, discomfort, aesthetics, infection, and function. These are also sometimes confused with, or superimposed by, various anxieties (Table 4.5).

The clinician’s task is to identify and propose relevant and appropriate solutions for the patient’s problems. The complicating aspect in this task is that the search for a single direct cause–effect relationship between a presenting feature and cause (Table 4.6) is confounded by the many sources of the presenting complaint (Table 4.7). The clinician must therefore appreciate the potential decision-tree and be ready to filter the received information through their diagnostic sieve to derive the single or as may be the case, multiple superimposed causes.

The intelligence gathering involves three sources of information, the history, examination and special tests.

History taking

Although a patient attends the dentist to identify and resolve their problem, they will often have a preconception about the origin of the problem, which may result in them limiting the scope of information they may be prepared to share with the clinician. There may be a need to break the preconception first so as to enable the patient to be more open and free with the sharing of their experience and insight. The importance of the detail for obtaining a resolution for the patient should not be underestimated.

Another curious problem in free information sharing is the patient with an “intellectual ego”, who becomes very defensive when asked a basic question, such as “can you describe the pain?” They may respond with, “Well, it is just a toothache”; suggesting that they somehow feel it beneath themselves to share such basic insight with the expert whose responsibility they believe it is to identify and resolve their problem. The real problem often is that they find it difficult to articulate their experience and feel diminished by not being able to do so. They may be pacified to learn that toothache comes in many forms and it can indeed be very difficult to describe for most people but that attempting to do so would help to identify their problem. Such grudging compliance may sometimes also hide other issues, to which the dentist should be alert.

To capture the patient’s attention and confidence requires many things, including a confident approach by the dentist, which in turn, demands sound knowledge and experience. The patient should be allowed to relate the details of their problem in their own words (as iterated by Wilfred Trotter) but the process should be managed to make it ordered, systematic and free of digression. If necessary, the clinician should be prepared gently but firmly to redirect the patient’s thoughts and memory if the information presented is incomplete.

The purpose is to get the patient to relate their experience as accurately as possible. The difficulty in achieving this in endodontic patients is potentially multilayered. The patient’s experience of their problem may have affected their state of mind due to anxiety, loss of sleep, loss of appetite and a general feeling of malaise. In addition, the patient may not have the vocabulary to describe their experience or the memory to recall it. While the dentist is trained to receive information in a particular order and has a set vocabulary for what may be experienced by the patient, they may not have personal experience of the problem. Conversely, the patient is not trained to describe their experience, especially using the “set” vocabulary and order, in which the dentist is trained to receive it. Information exchange would be significantly enhanced by dentists acquiring personal experience of the full range of problems that they have to deal with (but this may prove impractical or unethical!). The challenge is therefore one of inadequacy of information exchange.

Listen carefully to the patient’s explanation of their condition and use the patient’s own words to record it. Obtain a detailed description of any pain: its nature or character (sharp, dull, aching, throbbing, radiating); continuous or intermittent; initiating, exacerbating or relieving factors; duration; frequency; association with time of day, events, cycles (e.g. menstrual), habits, eating, drinking, physical or mental activity, etc, should all be noted; the effectiveness of analgesics should be recorded.

Medical history

A medical history is taken to find out whether the patient has any health problem or is taking medication that could affect the treatment. The most convenient way of recording such information is to use a checklist that is kept in the patient’s file, such as that shown in Table 4.8.

There is no medical condition that specifically and definitively contraindicates endodontic treatment, however, if there is any doubt, it is best to consult the patient’s medical supervisor. Conditions such as diabetes mellitus, bleeding disorders, anticoagulant therapy, blood-borne viruses, immunosuppression or epilepsy may affect treatment. The incidence of infective endocarditis in patients with cardiac abnormalities is increased with diabetes mellitus, immunosuppression, alcohol dependence, haemodialysis and intravenous drug abuse. In the UK, guidelines published by the National Institute of Clinical Excellence do not recommend the prescription of antibiotic prophylaxis for infective endocarditis.

The initial consultation is most effectively carried out beside a desk with both patient and clinician seated; patients find this less stressful than immediately being asked to sit in a dental chair (Fig. 4.2).

Clinical examination

Intraoral

The purpose of the oral examination is multifold. The first remit is direct visual detection of any variation from normal. The direct visual examination is facilitated by drying the tissues, use of good illumination, transillumination and magnification. This is secondarily followed by tactile manipulation of the affected part to decipher any further variations from normal. Finally, direct stimulation (by air, fluids, touch, pressure, percussion or electrical current) of affected parts may be used to reproduce or elicit the complaint or symptoms. Local anaesthesia may also be used to aid further location of pain by selectively abolishing sensation.

The intraoral soft tissues, oral hygiene (Fig. 4.7), general periodontal condition (Fig. 4.8), presence of caries (Fig. 4.9), missing or unopposed teeth (Fig. 4.10), quality and quantity of dental treatment (Fig. 4.11), tooth surface loss and faceting (Fig. 4.12) should all be assessed.

Soft tissue examination

The soft tissues, consisting of the cheek mucosa, tongue, floor of mouth, palate, sulcular fold, and those overlying the alveolus should all be assessed, after wiping with gauze, by direct visual observation for signs of inflammation, sinus tract openings, induration, swellings, fibroepithelial growth, ulcers or discoloration (Fig. 4.13).

The purpose of tactile stimulation is to determine whether the tissues are allodynic, hyperalgesic, tender or normal. A light touch may be applied, such as with a cotton bud to see if pain is elicited, indicating neuropathic changes. An increasing degree of force is applied by finger palpation to determine the presence of tenderness, which the patient is asked to confirm. The areas of altered sensation should be mapped on a diagram in the records (Fig. 4.14).

Hard and soft swellings should also be recorded on diagrams for extent, site, size, texture, consistency (bony, firm, fibrous, soft), mobility, fixity and fluctuance. Soft swellings should be palpated with two fingers to detect fluctuance. One finger is placed at either end of the swelling and pressure applied; if the swelling is fluctuant, movement of the fluid beneath the oral mucosa will be felt.

Periodontal examination

A general periodontal examination should be performed to characterize the periodontal status as part of the overall treatment plan, resulting in a basic periodontal examination (BPE) score (Fig. 4.15). The purpose is to determine and segregate any problems arising from marginal periodontal problems. More specifically, it is essential to exclude local, deep, isolated probing defects, signalling tooth anomalies, fractures, or sinuses (see Chapter 12).

A part of this assessment includes a determination of any periodontal overloading, manifesting in tooth mobility, fremitus or tooth drifting. Mobility of a tooth is assessed by placing a finger on one side and pressing with an instrument or another finger from the other (Fig. 4.16). The amount of movement is judged in relation to an adjacent tooth. Mobility may be graded as slight (grade 1), which is considered normal, moderate (grade 2), or extensive (grade 3) in a lateral or mesiodistal direction, combined with vertical displacement in the alveolus (Table 4.10).

Table 4.10

Miller classification (tooth mobility)

Class I Tooth can be moved less than 1 mm in the buccolingual or mesiodistal direction
Class II Tooth can be moved 1 mm or more in the buccolingual or mesiodistal direction
No mobility in the occlusoapical direction (vertical mobility)
Class III Tooth can be moved 1 mm or more in the buccolingual or mesiodistal direction
Mobility in the occlusoapical direction is also present

Tooth examination

Direct visual examination of teeth, following drying and under good direct illumination, should consist of a general assessment of the dentition, starting with the teeth present, their restorative status judged in terms of caries, restorations (their quality and extent), tooth surface loss (attrition, erosion, abrasion, abfraction), cracks, fractures and infractions. The number and distribution of the asymptomatic teeth should be characterized in a general summary.

The specific endodontically involved teeth will require a more detailed assessment as may adjacent teeth, which might act as controls and potential future abutments. Apart from the assessments mentioned above, the teeth will need to be manipulated in a variety of ways.

Transmission of a powerful light through teeth will show interproximal caries and (of particular interest in endodontics) cracks, infractions and fractures. Extraneous light is reduced; the fibreoptic light placed next to the neck of the tooth and moved along its surface. The light will not pass across the fracture line due to reflection, so the part of the tooth nearest to the light is bright and that beyond the fracture remains dark: Figure 4.17 shows this effect. Figure 4.18 shows a mandibular first molar with a coronal restoration removed – a fracture line is visible in the distal wall.

Pressure or force may be applied to teeth to elicit different types of information about the periodontium and the tooth. Pressure may be applied to teeth in different directions so that they act as instruments of palpation of the periodontal ligament. Just as palpation of the soft tissues is graduated, so pressure application to teeth is graduated by slowly increasing it. Such manipulation may help locate the presence of localized inflammation in the periodontal ligament.

At the extremes of the pressure stroke, the tooth may begin to deform allowing any cracks to open. This, in a vital tooth, is detected as a sharp dentinal pain, which may be felt on pressure application or release. In a non-vital tooth, a periodontal sensation, rather than a dentinal sensation is evident. Since cracks may be localized to individual cusps, this examination is enhanced by the use of a hard or viscous substance (such as a Burlew disc, rolled rubber dam, wooden stick, an inlay seater or tooth slooth®), which facilitate isolation of increased pressure to individual cusps (Fig. 4.19).

Using an impact force rather than graduated pressure, allows a different sort of assessment as the tooth moves differently in the viscoelastic periodontal ligament. Gentle tapping with a finger (both vertically and laterally) and then with an instrument will locate a tender tooth but it is a harsher test and usually gives a slightly different result to a pressure test (Fig. 4.20). If ankylosis of a tooth is suspected, tapping with an instrument handle in the long axis of the tooth will confirm the diagnosis: an ankylosed tooth has a distinctive high-pitched ring.

Pulp testing

Recently, the alternative term “sensibility testing” has come into common dental parlance. The authors feel the use of this term is incorrect. The test stimulates Aδ nerve fibres, which are the same nerves that respond to dentinal stimulation, albeit via the dentinal tubules and the hydrodynamic mechanism. The term “sensitivity” testing would, therefore seem more appropriate, although the term sensibility has the advantage of distinguishing between stimulation of Aδ nerve fibres directly versus indirectly via the hydrodynamic mechanism. Although the terms, sensitivity and sensibility are cited interchangeably in the English dictionary, the former term is better used to depict physical response and the latter term emotional response.

As the pulp is not open for direct inspection of its status, an indirect method is required. As yet, there is no means for imaging the pulp tissues to achieve this insight. Current methods, therefore merely serve to stimulate the pulp in the hope of eliciting a neural (Aδ fibre) response, which serves as a surrogate measure for determining that the nerve function viability stands for pulp viability. This does not though mean that the pulp is inflammation-free. The outcome sought is therefore either “positive response” or “negative response”. Some research methods assess the presence or absence of a viable blood supply (laser Doppler, pulse oximetry) but these instruments have not yet been developed for routine clinical use. Contemporary pulp testing can quantify neither disease nor health, and should not be used to judge the degree of pulpal disease. Pulp tests are best used to determine the existence of pulp necrosis and all are prone to false positives and negatives. Each type of pulp test works through a slightly different mode of stimulation and, therefore, it is prudent to use all of them to triangulate a consensus.

Electric pulp tester

The electric pulp tester (EPT) delivers a graduated increase in electric current (alternating or direct) to excite a response from the Aδ nerve fibres within the viable pulp. Most modern pulp testers are monopolar, meaning there is only one probe.

An example of a pulp tester, the Analytic Technology Endo Analyser, is shown (Fig. 4.21a). This instrument has a dual function acting as both a pulp tester and an electronic apex locator (EAL). When used as a pulp tester, a pulsating stimulus is produced starting at a low value, which increases automatically. The pulse amplitude of the stimulus begins at 15 volts and rises to a maximum of 350 volts.

Pulp testing technique

The test and control teeth should be dried and isolated with cotton wool or rubber dam (see Fig. 4.21b), the latter applied as small strips placed between the teeth. Contacts may also be isolated by inserting acetate strips between teeth. A conducting medium must be used – the one most readily available is toothpaste. The pulp tester is applied to the middle third of the tooth, avoiding contact with the soft tissues, and any restorations. A lip electrode is placed over the patient’s lip. If the pulp is vital the patient describes feeling a sensation which is variously described as tingling, vibration, pain, shock. Before testing the tooth in question, it is important to educate and acclimatize the patient to the sensation first on a control tooth. The patient is instructed that they should only respond to a sensation that matches the one elicited from the control tooth (assuming the pulp in this tooth is normal). Asking the patient to respond to any sensation will yield a false positive because if the potential difference is high enough, a sensation could be elicited from the periodontal ligament or adjacent teeth. A more user-friendly method is to ask the patient to hold the lip electrode. The plastic cable is held in one hand and the metal electrode between the forefinger and thumb of the other hand as shown in Figure 4.21c. This method allows the patient to have control by releasing their finger grip on the metal electrode when they feel the defined (not any) sensation; thus reducing the element of an anxiety-driven response. Electric pulp testers should be used with caution on patients who have a cardiac pacemaker; although modern pacemakers are shielded from electrical interference.

Pulp testing of crowned teeth is possible provided a small area of dentine or enamel is available for electrical contact without touching the gingival tissue. A special tip for the Analytic Technology pulp tester (see Fig. 4.21d) is being used on the patient shown in Figure 4.21e. Electric pulp testing cannot discriminate partial pulp necrosis as may happen in the different roots of a molar tooth.

Heat

Dry heat

This can be delivered with a commercially available, electrically-heated element, or else crudely, commonly available dental surgery materials may be deployed. The end of a stick of gutta-percha or composition (3 mm) is gently heated in a flame, tested on the gloved hand for warmth and lack of adherence and applied to the suspect tooth. The tooth surface should be lightly coated with petroleum jelly to prevent the composition/gutta-percha from sticking (Fig. 4.22); local anaesthetic should be kept to hand in case of a sharp reaction. Another crude method which has been suggested but is not recommended here, is to generate heat by running a rubber wheel on the tooth using a standard hand-piece (Fig. 4.23).

Hot water

Patients reporting pain due to hot food or drink do not always respond to the above tests. The stimulation requires that the heated medium penetrates particular parts of the mouth and reaches the involved tooth in the same way. This situation can only be replicated using the appropriate medium, normally hot water. Hot water should be sipped and held in the mouth, first over the mandibular quadrant on the affected side and then over the maxillary quadrant if this does not elicit a response. If this fails, an alternative method is to use rubber dam to isolate each tooth in turn and then flood the site with hot water (Fig. 4.24), the temperature of which must simulate the hot beverage eliciting the patient’s pain. If a response is obtained, the suspect tooth is anaesthetized and the heat test repeated.

Cold

Several methods can be used to deliver this test; the difference between them lies in how the reduced temperature is achieved and, therefore, what the temperature is (Table 4.11). The simplest and most common test is a blast of air from the triple syringe. Another common method is t/>

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Jan 2, 2015 | Posted by in Endodontics | Comments Off on 5: Diagnosis of endodontic problems
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