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.

Table 4.1

Definitions of diagnosis

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).

Table 4.2

Prior conditions for accurate diagnosis

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).

Fig. 4.1 Distributions for normal and disease states without (a) or with (b) overlapping presentations

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.

Table 4.3

Processes in diagnosis

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.

Table 4.4

Simplified classification of endodontic conditions

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.

Informed consent and record-keeping

The principle of informed consent is that the clinician informs the patient about the procedures (history, examination, special tests) and their risks; the patient of a sound and capable mind weighs the risks and gives permission for the procedure to be undertaken. This permission should ideally be recorded on a signed consent form. The patient may withdraw consent at any time, when the dentist must stop, otherwise they could be in breach of the common law of assault.

Accurate, clear records must be kept of all presenting, diagnostic and treatment information. What is written on a patient’s record card and in reports to specialists or referrers will be used as evidence in any legal disputes.

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).

Table 4.5

Patients’ presenting complaints and anxieties

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.

Table 4.6

Sources of the presenting complaints

Table 4.7

Cross-tabulation of Endodontic conditions with possible presenting complaints

CTS: crack tooth syndrome; H/C: hot/cold; TTP: tender to percussion

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

History taking

Wilfred Trotter on listening

the power of attention, of giving one’s whole mind to the patient without interposition of anything of one’s self.

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.

Table 4.8

Checklist for recording patient information

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).

Fig. 4.2 Consultation

Dental history

The patient’s attitudes to dental treatment must be assessed during the first appointment to determine the patient’s likely compliance. It is appropriate to assess the patient’s previous record of dental care and their compliance with it. Their experience (positive or negative) and economic status may determine their current attitude to treatment. Previous negative experiences may also have created a nervous or anxious predisposition that may compromise or alter compliance. Their perception of endodontic treatment and ability to withstand long or short sessions is crucial to judge from the outset. Patients may prefer a particular time of day for personal or medical reasons.

Social history

Habits such as smoking and alcohol use should be characterized for their effect on the patient’s well-being and healing potential.

Clinical examination

Extraoral

Extraoral examination is carried out for facial swelling, asymmetry, tenderness of muscles of mastication and the temporomandibular joints, nerve responses (Table 4.9) and the presence of enlarged lymph nodes. Facial swelling is best viewed from above the patient (Figs 4.3, 4.4).

Table 4.9

Examination of cranial nerve injury

Fig. 4.3 Any facial swelling should be noted

Fig. 4.4 Facial swelling is best seen from above the patient

Ease of oral access

An assessment should be made of the ease of access, particularly to the posterior part of the mouth. As a general guide, if a patient’s mouth will not open wide enough to allow two fingers to pass between the incisors, root-canal treatment of the molars may be compromised (Fig. 4.5). Some patients, with small mouths, particularly the elderly, find it difficult to keep their mouth sufficiently wide open for long periods, using a mouth prop, which they may relax upon during treatment, does help (Fig. 4.6).

Fig. 4.5 Access assessed with two fingers

Fig. 4.6 Mouth props

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.

Fig. 4.7 Poor oral hygiene

Fig. 4.8 Periodontal condition

Fig. 4.9 Loose bridge abutment with caries beneath

Fig. 4.10 Missing and unopposed teeth

Fig. 4.11 General dental state

Fig. 4.12 Tooth surface loss and faceting

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).

Fig. 4.13 Soft tissue examination

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).

Fig. 4.14 Two-dimensional face diagram for mapping areas of altered sensation

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).

Fig. 4.15 Example of BPE score grid and criteria for coding

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

Fig. 4.16 Mobility

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.

Fig. 4.21 (a) Unit has a dual function both as a pulp tester and an apex locator; (b) pulp tester applied to buccal surface of tooth isolated with strips of rubber dam (toothpaste used as a conducting medium); (c) patient controls the pulp tester; (d) special tip for pulp testing beneath crowns; (e) pulp testing beneath crown

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.