DIAGNOSIS OF PULPAL DISEASES

Presenter: Dr. R.O. Kekere-ekun

Keywords: Diseases, Pulp, Diagnosis.

OBJECTIVE

● Describe the pulp, its functions and response to irritants/injuries.

● List the clinical classification of the diseases of the pulp.

● List the various causative factors involved in pulp diseases.

● Describe the diseases of the pulp in terms of signs and symptoms.

● Identify the potential sequelae of the diseases of the pulp.

● Itemize the essentials of diagnosis of the diseases of the pulp.

● List the various clinical examinations and tests that can be used to make a diagnosis for the diseases of the pulp as well as describe what the results of each test indicate.

● Describe how to conduct pulp tests and identify materials that can be used to conduct pulp tests.

● Describe the different clinical pulpal conditions according to the following aspects:

–Patient dental history; –Patient signs and symptoms; –Pulp test results; –Radiographic findings.

● Note the top differential diagnosis of the diseases of the pulp.

INTRODUCTION

The dental pulp is a unique tissue and its importance in the long-term prognosis of the tooth is often ignored by clinicians. It is unique in that it resides in a rigid chamber which provides strong mechanical support and protection from the microbial rich oral environment. If this rigid shell loses its structural integrity, the pulp is under the threat of the adverse stimuli from the mouth, such as

1 caries, cracks, fractures and open restoration margins, all of which provide pathways for micro-organisms and their toxins to enter the pulp. The pulp initially responds to irritation by becoming inflamed and, if left untreated, this will progress to pulp necrosis and infection. The inflammation will also spread to the surrounding alveolar bone and cause periapical pathosis. The magnitude of pulp-related problems should not be underestimated since their most serious consequence is oral sepsis, which can be life threatening, and hence correct diagnosis and management are essential. Clinicians must have a thorough understanding of the physiological and pathological features of the dental pulp as well as the biological consequences of treatment interventions.

Whenever any disease is to be treated, there are several general principles that must be followed. The first, and perhaps the most important, is to identify the disease and its cause which can usually be achieved with a thorough history, clinical examination and appropriate diagnostic tests. Identification of the cause is essential since it must be removed as an integral part of the treatment of the disease. Then the other general principles of treatment can be followed and these include removing the effect of the disease, restoring the tissues to their normal function, monitoring the healing and stability over time, and preventing recurrence of the disease.

The importance of correct diagnosis and treatment planning must not be underestimated. There are many causes of facial pain and the differential diagnosis can be both difficult and demanding.

THE DENTAL PULP

Pulp tissue is alive and functioning:

● Surrounded by the hard structures of teeth [enamel and dentine].

● It, in fact, has produced much of that very hard structure [odontoblast secreting pre- dentine].

● It can produce more hard structure as a defense system [part of inflammatory response].

● It provides nourishment for the odontoblasts which lines its surface.

● These odontoblasts have long processes which extend approximately one-third as far as the amelodentinal junction.

● The tubules beyond the odontoblast processes are normally patent and filled with tissue fluid.

2 ● When irritants are applied to the distal ends of the dentinal tubules, the odontoblasts will form more dentine, within the pulp as secondary dentine, within tubules as peritubular dentine, or lead to occlusion of the tubules as mineralized deposits as tubulae sclerosis.

● The more the area of exposed dentine, the greater is the effect on the pulp.

● The pulp and dentine can thus be regarded as one interconnected tissue–the dentino- pulpal complex, protected from irritation by an intact layer of enamel.

Pulp tissue is alive and functioning:

● Pulp has the potential to produce a robust inflammatory response to irritation/infection.

● By its inflammatory responses, it also produces pain for the patient.

● Pulp tissue can break down and become necrotic.

● Infection/inflammation can spread throughout the pulp tissue and out the tooth to the surrounding tissues.

● Therefore, the pulp tissue requires careful protection in all that we do in dentistry to avoid the negative responses and to encourage the positive ones.

● This affects diagnostic decisions, restorative decisions, prep and cavity designs, methods of preparation, and materials used.

THE NORMAL TOOTH

● A tooth with a non-inflamed pulp;

● It is asymptomatic;

● It exhibits a mild to moderate transient response to thermal and electric pulpal stimuli;

● This +ve response subsides almost immediately after such stimuli are removed;

● The tooth and its attachment apparatus do not cause a painful response to percussion and palpation;

● Radiograph will reveal no pulpal or periradicular pathosis;

3 ● However, as a result of caries, restorative procedures, trauma, thermal, physical or chemical injury, etc. the normal pulp may become inflamed and present itself clinically as either a reversible or irreversible pulpitis.

CLASSIFICATION OF THE DISEASES OF THE PULP

Introduction

It is widely accepted that the most common cause of pulp and periapical diseases is the presence of bacteria within the involved tooth, and the most common pathways of entry for these bacteria are via caries, cracks, fractures and open restorative margins. Other possible pathways for bacterial penetration are associated with periodontal disease and dental trauma.

Pulpal inflammation and necrosis are also initiated by restorative procedures, trauma, chemical irritation and severe thermal stimulation.

These inflammatory lesions cause localized oedema and a resulting increase in intra- pulpal pressure and cell death. Increased damage associated with an inflammatory exudate cause local collapse of the venous part of the local microvasculature. This causes local tissue hypoxia and anoxia resulting in localized necrosis, the chemical mediators of which cause further localized oedema, completing the cycle.

EXPOSED SENSITIVE DENTINE

This may result from gingival recession or surgery producing exposed root surfaces, or it may result from a failing restoration or caries exposing dentine to oral fluids. The patient will usually complain of sensitivity to hot, cold, and sweet food and drink, but the sensitivity (rather than pain) is often poorly localized. It may indeed be generalized in several areas of the mouth. Pulp tests applied to enamel surfaces will produce a normal response, but if the exposed dentine surface is stimulated either thermally or electrically, or is scratched with a probe, there may be an increased response. The teeth are not tender to percussion.

CRACKED CUSPS

Cusps may crack either superficially or deep into the tooth, whether the tooth is restored or not. The crack may involve the pulp or pass only through enamel and dentine. The symptoms are often poorly localized and may occur only periodically. Sometimes there is a sharp pain on biting hard on tough food, and occasionally with thermal stimuli. Thermal and electrical pulp tests are often inconclusive and the tooth may not be tender to percussion although pressure laterally on individual cusps may produce pain. Transillumination may help to show the crack, or applying disclosing solution or other

4 stain to the tooth may reveal it. Unfortunately, many teeth show multiple cracks and do not cause symptoms (perhaps because these cracks only involve enamel), and thus it is difficult to be sure that any crack that is seen is actually the cause of the pain. A useful diagnostic test is to ask the patient to bite on a cotton-wool roll. Pain is often felt when the pressure is released rather than when it is applied. Sometimes, when the restoration is removed from a suspect tooth, the crack is seen at the base of the cavity and these deep cracks are more likely to cause symptoms.

PULP HYPEREMIA

This change is characterized by a short and well localized pain in response to physical or chemical stimuli which diminishes after a causing effect stops. The treatment in this case is an indirect pulp capping.

REVERSIBLE PULPITIS

● A review of the dental history reveals that the patient is experiencing an intermittent, exaggerated response to a stimulus such as cold or hot. However, the discomfort does not linger after the stimulus is removed, i.e., the discomfort or pain disappears when the stimulus is removed.

Diagnostic findings from clinical and radiographic exams:

● Restoration and/or caries associated with the involved tooth;

● Periodontal ligament (PDL) space is WNL;

● EPT: Positive response;

● Thermal tests: Non-lingering, exaggerated response to cold and/or hot;

● Percussion: No unusual sensitivity.

● If the etiology of the inflammation is identified and corrected, the pulp will return to a normal state and the symptoms will disappear. However, if the inflammation continues, localized areas of tissue necrosis will occur which can progress to an irreversible pulpitis.

IRREVERSIBLE PULPITIS

● It is accepted that irreversible pulpal disease occurs when trauma inflicted on the pulpal tissues exceeds their reparative capacity. Such a pathological insult can occur through the invasion of bacteria or biochemical toxins in deep carious lesions, cracks, fractures, open restorative margins, or by direct trauma to the pulp during restorative therapy.

5 ● Irreversible pulpitis may be acute, subacute, or chronic, and it may be partial and total. Clinically, acute one is symptomatic, whereas the chronic is asymptomatic. At this stage, the dynamic changes in the pulp are always occurring.

SYMPTOMATIC IRREVERSIBLE PULPITIS [ACUTE PULPITIS]

● The patient presents with a history of spontaneous intermittent or continuous paroxysms of pain and/or an exaggerated response to hot or cold, which lingers when the stimulus is removed.

● Because the pulp does not contain proprioceptive nerve fibers, patients will have a difficult time localizing the origin of their pain. Thus, referred pain should be considered during the diagnostic workup.

● The pain caused by cold stimulation can be relieved by heat, and similarly, the pain caused by heat can be relieved by cold.

● In some cases of irreversible pulpitis, cold actually alleviates the pain, and the patient might present with a glass of ice water. This finding should then be used as a diagnostic test to determine the etiology of the pain.

Other diagnostic findings from clinical and radiographic exams:

● Extensive restoration and/or caries may be associated with the involved tooth;

● NOTE: There may be some evidence of the cause of the pulpitis, such as caries or a heavily restored tooth, but this is not a reliable way of diagnosing the affected tooth. Sometimes the tooth in the quadrant with the most obvious gross caries has been non-vital for some time and is symptomless, but another tooth with less obvious caries, perhaps under an existing restoration, is the source of the pulpitis.

● PDL space may/may not be widened;

● EPT: Positive response; thermal tests–exaggerated response which lingers after the stimulus is removed;

● Percussion: may/may not elicit a painful response.

ASYMPTOMATIC IRREVERSIBLE PULPITIS [CHRONIC PULPITIS]

● If the inflammatory exudate causing the increase intrapulpal pressure and resultant moderate to severe pain escapes from the surrounding dentin via a carious exposure or loss of restoration, the irreversible pulpitis may become asymptomatic. Thus, it can develop by the conversion of a symptomatic one into a quiescent state.

6 ● It also can caused by long and low-grade pulp irritant (carious lesions), traumatic injury.

TYPES OF ASYMPTOMATIC PULPITIS:

HYPERPLASTIC PULPITIS [PULP POLYP]

● Clinically, it is a reddish cauliflower-like overgrowth of pulp tissue through and around a carious exposure. It is characteristically found in young people since the generous vascularity of the pulp.

INTERNAL RESORPTION

● It is a resorption of the dentine from the pulp outward, which is often caused by trauma or pulp capping. It is usually can be diagnosed by radiography.

PULP NECROSIS

● Death of pulp, may result form an untreated irreversible pulpitis or may occur immediately after a traumatic injury that disrupts the blood supply to the pulp.

● Necrosis may be partial or total, and the partial may exhibit some of the signs and symptoms of an irreversible pulpitis.

● Teeth with total pulpal necrosis are usually asymptomatic unless the periradicular area is involved.

● Occasionally with anterior teeth the crown gets discoloured and becomes darken.

RETROGRADE PULPITIS

● The process starts with the formation of periodontal lesions which are initiated by deposits of plaque and calculus.

● Inflammatory mediators cause destruction of gingival connective tissue, periodontal ligament and alveolar bone. Alteration of the root surface occurs by loss of the outer cementoblast layer and results in shallow resorptive lesions of cementum.

● Endotoxins produced by plaque bacteria also have an irritant effect on overlying soft tissue, preventing repair.

7 ● The pathogenic bacteria and inflammatory products of periodontal disease may gain access to the dental pulp through accessory canals, apical foramina, or dentinal tubules. Local pulpal inflammation and necrosis results in “retrograde pulpitis.”

● Although periodontal disease has been shown to have a cumulative damaging effect on the pulp tissue, it is said that total disintegration of the pulp is only a certainty if bacterial plaque involves the main apical foramina, compromising the vascular supply.

● Evidence to the contrary shows inflammatory lesions, as well as localised necrosis of pulp tissue observed adjacent to lateral canals in teeth exposed by periodontal disease. As the effects of caries and noxious stimuli are also cumulative, the pulp looses some of its recuperative power with each added insult.

● Periodontal occlusal trauma may, in theory, cause pulp ischemia, especially in teeth with a greatly reduced periodontal support further adding to cumulative detrimental effects mentioned previously.

● Lateral, accessory canals and dentinal tubules are therefore potential sources of pulpitis and pulpal necrosis.

● The presence of an intact cementum layer is important for the protection of the pulp from pathogenic agents produced by the plaque bacteria.

● Therefore the exposure of dentinal tubules by the removal of cementum due to rigorous scaling and root-planing for the treatment of periodontal disease will allow bacterial invasion of the tubules. This would increase the likelihood of cumulative damage to the pulp.

● A retrograde pulpitis follows local pulpal inflammation and necrosis and can result in a progression to total necrosis of the pulpal tissues.

POTENTIAL SEQUELAE OF THE DISEASES OF THE PULP

● Pulpal inflammation may spread through the root canal and the apical foramen into the periapical tissue. In fact, periapical inflammation usually occurs before total necrosis of the pulp has taken place. The response in the periradicular or periapical area may be symptomatic (acute) or asymptomatic (chronic).

8 ● Spread can also occur via the lateral or accessory root canals opening on the lateral surface of the root at any level or on the pulpal floor and into the furcation area in multi- rooted teeth. As the root canal system is a low compliance system an increased intrapulpal pressure following inflammation and localized oedema may cause toxic agents to be expressed through patent channels, such as the apical foramen, lateral and accessory canals and dentinal tubules, which can result in a retrograde periodontitis.

PERIAPICAL DISEASES

ACUTE PERIAPICAL PERIODONTITIS (APP)

Causes:

● Extension of pulpal disease into the periapical tissue.

● Occlusal trauma from a high restoration or from chronic bruxism

● Overextension of endodontic instruments, sealing or obturating materials beyond the apical foramen.

Diagnostic findings:

● The patient presents with a tooth, which is extremely tender to touch, occlusion or pressure.

● If resulting from an extension of the pulpal lesion, the tooth may also exhibit the signs and symptoms of irreversible pulpitis.

● The one diagnostic sign, which is pathognomonic of a tooth with APP, is an extreme response to percussion.

● In addition, there is tenderness to palpation over the apex of the tooth in the buccal sulcus.

● Radiographically, the apical periodontal ligament may appear slightly widened or normal.

ACUTE PERIAPICAL ABSCESS (APA)

● It implies a painful, purulent exudates around the apex.

● Results from proliferation and invasion of large numbers of bacteria from the infected pulp tissue into the periapical tissue;

9 ● Results when the patient’s immune system is not able to combat the invasion.

● Clinically, rapid onset of slight to severe tender swelling either intra-orally or on the face and mild to severe pain.

● Sometimes the patient presents before the swelling has appeared or after it has spontaneously burst or subsided.

● In addition, the patient may exhibit systemic manifestations such as fever, chills, lymphadenopathy, headache and nausea.

● In most cases, the tooth will elicit a positive response to percussion, and the periradicular area will be tender to palpation.

● The spread of infection from the apices of teeth follows well-defined patterns. For example, an acute apical abscess on an upper lateral incisor commonly points onto the palate, whereas on the upper canine tooth it points facially and causes swelling of the cheek and may close the eye.

● Since the reaction to the infection occurs very quickly, the involved tooth may/may not show radiographic evidence of a widened PDL space.

CHRONIC PERIAPICAL PERIODONTITIS (CPP) [CHRONIC PERIAPICAL GRANULOMA]

● Chronic apical periodontitis implies long-standing asymptomatic inflammation around the apex.

● Although chronic apical periodontitis tends to be asymptomatic, there may be occasional slight tenderness to biting and percussion.

● If the immune system is able to combat the influx of bacteria, a low-grade long-standing lesion forms in the periapical area. As long as the irritants keep emanating from the root canal system, the soft tissue lesion keeps expanding at the expense of the surrounding bone.

● Only biopsy and microscopy examination can reveal whether these apical lesions are dental granulomas, abscesses, or cysts.

● Clinically, the CPP is asymptomatic and is detected only radiographically by the presence of a small or large, well-circumscribed or diffuse periapical radiolucency. Thus, this lesion is often detected during a routine examination, and the patient is surprised that it is present.

10 ● Diagnosis is confirmed by the presence of this periapical radiolucency that may be either diffuse or well-circumscribed, the absence of pulp vitality, and a sinus tract.

CHRONIC SUPPURATIVE PERIODONTITIS (CSP)

● If the periapical lesion establishes drainage by breaking through the cortical plate into the oral cavity, a diagnosis of chronic suppurative periodontitis is made.

● Clinically, the patient presents with a sinus tract, which can be traced with a gutta- percha point to determine its source radiographically.

● The patient is usually asymptomatic because the sinus tract allows for drainage of any purulent exudate forming in the periradicular area.

● The radiographic exam usually reveals a periradicular radiolucency associated with the involved tooth.

● The palpation, percussion, and ‘vitality’ tests render no response.

PHOENIX ABSCESS

● A phoenix abscess is an acute exacerbation of a chronic apical periodontitis resulting from an increase in the virulence of the bacteria in the lesion and/or a decrease in the patient’s resistance.

● The patient exhibits the same signs and symptoms of an acute periapical abscess, the main difference being that the phoenix abscess is preceded by a chronic condition and there is apical radiolucency around the apex of the involved tooth.

ACUTE PERIODONTAL ABSCESS

● An acute periodontal (or lateral) abscess forms at the base of a deep periodontal pocket.

● The presentation is similar to that for acute apical periodontitis or acute apical abscess but the tooth may still be vital. This is because the inflammation is not the consequence of spread of infection from a necrotic pulp.

● Thermal and electric pulp test indicate the pulp is vital.

Levels of Pulp Therapy in Primary Teeth

11

The level of therapy depends upon the level of injury or disease. Therefore, careful diagnosis is vital.

ESSENTIALS OF DIAGNOSIS OF PULPAL DISEASES

IN BRIEF:

● Diagnosis can be defined as:

12 –The art of recognizing a disease or disease pattern;

–The art of distinguishing one disease from the other.

–The process of determining the nature of a disease or disorder by considering the patient’s signs and symptoms, medical background, and results of appropriate tests and X-ray examination.

● Under diagnosis, we employ:

–Procedures for diagnosis;

–Diagnostic aids/Diagnostic tools.

● An accurate diagnosis of the patient’s condition is essential before an appropriate treatment plan can be formulated for that individual.

● In other words, “Diagnosis must PRECEDE Treatment.” [DIAGNOSIS, THEN THERAPY]

● REMEMBER: “The fact that your patient gets well does not prove that your diagnosis was correct.”

● REMEMBER: “There is no royal road to diagnosis.”

● Diagnostic procedures encompass a review of:

●Case history: –Medical history; –Dental history; –Patient’s complaints; ●Clinical examination; ●Diagnostic tests

CASE HISTORY

● The purpose of a case history is to discover whether the patient has any general or local condition that might alter the normal course of treatment. As with all courses of treatment, a comprehensive demographic, medical and previous dental history should be recorded. In addition, a description of the patient’s symptoms in his or her own words and a history of relevant dental treatment should be noted.

Medical History

13 ● There are no medical conditions which specifically contra-indicate the treatment of pulp diseases, but there are several which require special care.

● The most relevant conditions are allergies, bleeding tendencies, cardiac disease, immune defects or patients taking drugs acting on the endocrine or CNS system.

● If there is any doubt about the state of health of a patient, his/her general medical practitioner should be consulted before any dental treatment is commenced. This also applies if the patient is on medication, such as corticosteroids or an anticoagulant.

● Medical history should reveal any medical condition or medication which might influence diagnosis, e.g. sinusitis, neoplasia, or treatment which may be influenced by dental procedures; this should include allergy.

A simple check list for a medical history (Scully and Cawson)

Anaemia Bleeding disorders Cardiorespiratory disorders Drug treatment and allergies Endocrine disease Fits and faints Gastrointestinal disorders Hospital admissions and attendances Infections Jaundice or liver disease Kidney disease Likelihood of pregnancy or pregnancy itself

Dental History

Dental history should discovers factors that may be important for diagnosis and treatment planning.

Patient’s Complaints

● History of present complaint is recorded briefly and preferably in the patient’s own words. Pain history is recorded to give information on the pain, but phrased to avoid leading questions. The questions may include: the nature, duration, site, periodicity, precipitating or relieving factors and associated symptoms.

● Listening carefully to the patient’s description of his/her symptoms can provide invaluable information. It is quicker and more efficient to ask patients specific, but not

14 leading, questions about their pain. Examples of the type of questions which may be asked are given below.

1. How long have you had the pain? 2. Do you know which tooth it is? 3. What initiates the pain? 4. How would you describe the pain? Sharp or dull Throbbing Mild or severe Localised or radiating 5. How long does the pain last? 6. Does it hurt most during the day or night? 7. Does anything relieve the pain?

● It is usually possible to decide, as a result of questioning the patient, whether the pain is of pulpal, periapical or periodontal origin, or if it is non-dental in origin.

● In cases of pulpitis, the decision the operator must make is whether the pulpal inflammation is reversible, in which case it may be treated conservatively, or irreversible, in which case either the pulp or the tooth must be removed, depending upon the patient’s wishes.

● If symptoms arise spontaneously, without stimulus, or continue for more than a few seconds after a stimulus is withdrawn, the pulp may be deemed to be irreversibly damaged. Applications of sedative dressings may relieve the pain, but the pulp will continue to die until root canal treatment becomes necessary. This may then prove more difficult if either the root canals have become infected or if sclerosis of the root canal system has occurred. The correct diagnosis, once made, must be adhered to with the appropriate treatment.

● In early pulpitis the patient often cannot localise the pain to a particular tooth or jaw because the pulp does not contain any proprioceptive nerve endings. As the disease advances and the periapical region becomes involved, the tooth will become tender and the proprioceptive nerve endings in the periodontal ligament are stimulated.

CLINICAL EXAMINATION

A clinical examination of the patient is carried out after the case history has been completed. The patient should be examined both extra- and intra-orally and may also need to be checked for pyrexia and blood pressure.

The temptation to start treatment on a tooth without examining the remaining dentition must be resisted. Problems must not be dealt with in isolation and any treatment plan should take the entire mouth and the patient’s general medical condition and attitude into consideration.

15 Extra-oral Examination

The patient’s head and neck region are examined for asymmetry, presence and extent of swelling, tender areas, lymphadenopathy, presence of extra-oral sinus tracts and presence of temporomandibular joint dysfunction.

Intra-oral Examination

An assessment of the patient’s general dental state is made, noting in particular the following aspects:

• Standard of oral hygiene. • Quantity and quality of restorative work. • Prevalence of caries. • Missing and unopposed teeth. • General periodontal condition. • Presence of soft or hard swellings. • Presence of any sinus tracts. • Discoloured teeth. • Tooth wear and facets. • Presence of cracks, fractures and open restoration margins.

DIAGNOSTIC TESTS

● The cause of the patient’s complaint should be identified.

● Keep in mind: Most of the diagnostic tests used to assess the state of the pulp and periapical tissues are relatively crude and unreliable.

● No single test, however positive the result, is sufficient to make a firm diagnosis of reversible or irreversible pulpitis.

● There is a general rule that before drilling into a pulp chamber there should be two independent positive diagnostic tests. An example would be a tooth not responding to the electric pulp tester and tender to percussion.

● Some or all, of the following diagnostic tests may be applied: Palpation, mobility test, percussion, periodontal examination, occlusal analysis, testing for possible cracked teeth, pulp sensitivity tests, transillumination, selective local anaesthesia, radiography (normally by using the paralleling technique and a beam guiding device for good reproducibility), colour matching and sinus tract exploration.

16 ● Some patients may have to be recalled at periodic intervals to compare some of the examination data from one time interval to another to make an accurate diagnosis of the onset, progression or arrest of a certain process.

Palpation

The tissues overlying the apices of any suspect teeth are palpated to locate tender areas. The site and size of any soft or hard swellings are noted and examined for fluctuation and crepitus.

Percussion

Gentle tapping with a finger both laterally and vertically on a tooth is sufficient to elicit any tenderness. It is not necessary to strike the tooth with a mirror handle, as this invites a false-positive reaction from the patient.

Mobility

The mobility of a tooth is tested by placing a finger on either side of the crown and pushing with one finger while assessing any movement with the other. Mobility may be graded as: 1 — slight (normal) 2 — moderate 3 — extensive movement in a lateral or mesiodistal direction combined with a vertical displacement in the alveolus.

Presence of a Sinus

A sinus over the apical region is strong evidence that there may be a necrotic pulp in a nearby tooth. Usually, but not always, the sinus discharges close to the apex of the affected tooth. If there is any doubt, and in particular when several teeth possibly have necrotic pulps, a useful investigation is to insert a gutta-percha point into the sinus and take a radiograph. This also helps to distinguish between periapical changes arising from a necrotic pulp and pathology elsewhere, such as a lateral root canal or lateral perforation of the root by instrumentation.

Radiography

● The radiographic exam should include evaluation of both suspected teeth (coronal examinations focusing on potentially open margins, pulp stones, etc, and radicular examinations focusing on loss of the lamina dura, periradicular radiolucencies or opacities, resorptive processes) as well as examination of other visible structures.

17 ● Radiography is the most reliable of all the diagnostic tests and provides the most valuable information. However, it must be emphasized that a poor quality radiograph not only fails to yield diagnostic information, but also, and more seriously, causes unnecessary radiation of the patient. The use of film holders, recommended by the National Radiographic Guidelines has two distinct advantages. Firstly a true image of the tooth, its length and anatomical features, is obtained (Fig. 3), and, secondly, subsequent films taken with the same holder can be more accurately compared, particularly at subsequent review when assessing the degree of healing of a periradicular lesion.

● A radiograph may be the first indication of the presence of pathology. A disadvantage of the use of radiography in diagnosis, however, can be that the early stages of pulpitis are not normally evident on the radiograph.

● If a sinus is present and patent, a small-sized (about #40) gutta-percha point should be inserted and threaded, by rolling gently between the fingers, as far along the sinus tract as possible. If a radiograph is taken with the gutta-percha point in place, it will lead to an area of bone loss showing the cause of the problem.

● It may be necessary to take radiographs from more than one angle, sometimes supplemented with bitewing and occlusal plane radiographs.

● The presence of a small or large, well-circumscribed or diffuse periapical radiolucency may indicate a periapical granuloma or cyst which are signs of a non-vital pulp.

● Bitewing radiographs are of more value in detecting caries and may need to be taken more often when assessing pulp and periapical diseases.

● Radiographs should be examined by using ideal viewing conditions with an X-ray viewing light box. A Binocuscope (Trollplast, Wollongbar, NSW) to block out peripheral light and to magnify the image (x2) may be employed for better viewing.

● However, errors can be made when normal structures, such as the mental foramen, the incisal canal, or the maxillary antrum are superimposed on the root. In these cases it should be possible to trace an intact lamima dura around the normal apex. Another rare cause of periapical radiolucency, which may be associated with a tooth with a vital pulp, is the osteolytic phase of Periapical Cemental Dysplasia.

Pulp Testing

● Pulp testing is often referred to as ‘vitality’ testing. These tests measure the neural response providing little information regarding the vascularity of the pulp.

18 ● Recent studies have shown that blood circulation and not innervation is the most accurate determinant in assessing pulp vitality as it provides an objective differentiation between necrotic and vital pulp tissue.

● In fact, a moribund pulp may still give a positive reaction to one of the following tests as the nervous tissue may still function in extreme states of disease.

● It is also, of course, possible in a multirooted tooth for one root canal to be diseased, but another still capable of giving a vital response.

● Pulp testers should only be used to assess vital or non-vital pulps; they do not quantify disease, nor do they measure health and should not be used to judge the degree of pulpal disease.

● Pulp testing gives no indication of the state of the vascular supply which would more accurately indicate the degree of pulp vitality.

● There are now recent advances in pulp vitality testing that detect blood flow in the pulp.

● A non vital tooth commonly becomes darker and less translucent than the corresponding vital tooth if it is not promptly treated by removing the necrotic pulp and root filing with an inert non-staining material. If the change is slight, particularly when the tooth is heavily filled, the difference in colour may be difficult to detect. Transillumination will help to detect slight changes in colour and particularly translucency.

Electronic Pulp Testing

● The electric pulp tester is an instrument which uses gradations of electric current to excite a response from the nervous tissue within the pulp. Both alternating and direct current pulp testers are available, although there is little difference between them. Most pulp testers manufactured today are monopolar.

● Electric pulp testers may give a false-positive reading due to stimulation of nerve fibres in the periodontium [Heat is conducted through the dentine to the periodontal membrane]. Again, posterior teeth may give misleading readings since a combination of vital and non- vital root canal pulps may be present.

● The use of gloves in the treatment of all dental patients has produced problems with electric pulp testing. A lip electrode attachment is available which may be used, but a far simpler method is to ask the patient to hold on to the metal handle of the pulp tester. The patient is asked to let go of the handle if they feel a sensation in the tooth being tested.

● The teeth to be tested are dried and isolated with cotton wool rolls. A conducting medium should be used; the one most readily available is toothpaste. Pulp testers should

19 NOT be used on patients with pacemakers because of the possibility of electrical interference.

● Teeth with full crowns present problems with pulp testing. A pulp tester is available with a special point fitting which may be placed between the crown and the gingival margin. There is little to commend the technique of cutting a window in the crown in order to do pulp test.

● When carrying out electrical or thermal tests, a normal tooth is first tested to demonstrate the sensation to the patient and also to act as a basis for comparison.

● Electric pulp testers have the advantage that initially they can be applied to the tooth with no electrical stimulus, and the current can be switched on and increased. This allows the patient to distinguish between the sensation of the tooth being touched and a stimulus applied. It also allows the test to be curtailed as soon as any sensation is felt rather than (if pulp is already hypersentive) suffering the application of hot or cold stimuli.

Thermal Pulp Testing

This involves applying either heat or cold to a tooth, but neither test is particularly reliable and may produce either false-positive or false-negative results.

Heat

There are several different methods of applying heat to a tooth. The tip of a gutta-percha stick may be heated in a flame and applied to a tooth.

Take great note that hot gutta-percha may stick fast to enamel, and it is essential to coat the tooth with vaseline to prevent the gutta-percha sticking and causing unnecessary pain to the patient, or damaging the pulp from overheat.

Another method is to ask the patient to hold warm water in the mouth, which will act on all the teeth in the arch, or to isolate individual teeth with rubber dam and apply warm water directly to the suspected tooth. This is explored further under local anaesthesia.

Cold

Three different methods may be used to apply a cold stimulus to a tooth. The most effective is the use of a –50°C spray, which may be applied using a cotton pledget.

A cold stimulus can also be applied by soaking a small pledget of cotton wool in ethyl chloride which cools by rapid evaporation, and then applying this to the tooth. Alternatively, an ethyl chloride spray may be used.

20 Finally, ice sticks may be made by filling the plastic covers from a hypodermic needle with water and placing in the freezing compartment of a refrigerator. When required for use one cover is warmed and removed to provide the ice stick. However, false readings may be obtained if the ice melts and flows onto the adjacent tissues.

For the above methods misleading results may occur:

False-Positive

● Multi-rooted tooth with vital plus non-vital pulp; ● Canal full of pus; ● Apprehensive patient.

False-Negative

● Nerve supply damaged, blood supply intact, e.g., after a blow, particularly in young patients; ● Secondary dentine formation; ● Large insulating restoration.

Recent Advances in Pulp Vitality Testing

The assessment of pulp vitality is a crucial diagnostic procedure in the practice of dentistry. Current routine methods rely on stimulation of Ad nerve fibers and give no direct indication of blood flow within the pulp. These include thermal stimulation, electrical or direct dentine stimulation. These testing methods have the potential to produce an unpleasant and occasionally painful sensation and inaccurate results (false positive or negative can be obtained in many instances). In addition, each is a subjective test that depends on the patient’s perceived response to a stimulus as well as the dentist's interpretation of that response. Recent studies have shown that blood circulation and not innervation is the most accurate determinant in assessing pulp vitality as it provides an objective differentiation between necrotic and vital pulp tissue. These recent advances in pulp vitality testing rely either on the detection of changes in the light absorption as it passed through the tooth, as in Photoplethysmography, Pulse Oximetry and Dual Wavelength Spectrophotometry or the shift in light frequency as it is reflected back from a tooth, as in Laser Doppler Flowmetry. This paper attempts to review the newer pulp vitality testing methods.

Pulse Oximetry

The pulse oximeter is a non-invasive oxygen saturation monitoring device widely used in medical practice for recording blood oxygen saturation levels during the administration of intravenous anesthesia. It contributes to the increased safety of general anesthesia. Pulse oximeter is a standard equipment in operating rooms and is routinely being used in other

21 acute care settings, including intensive care units, emergency rooms and endoscopy suites where sedation and analgesia are provided. Its wide acceptance in the medical field results from its ease of application and its capability of providing vital information about the patient’s status.

This device is currently under investigation in dental practice to detect pulpal blood circulation by virtue of its non-invasive and atraumatic nature. Specific objectives were to develop a design for a dental sensor (a modified finger probe) that can be successfully applied and adapted to the tooth and well suited to detect pulsatile absorbance.

The principle of this technology is based on a modification of Beer’s law, which relates the absorption of light, by a solute to its concentration and optical properties at a given light wavelength. It also depends on the absorbance characteristics of haemoglobin in the red and infra-red range. In the red region, oxyhaemoglobin absorbs less light than deoxyhaemoglobin and vice versa in the infrared region. Hence one wavelength was sensitive to changes in oxygenation and the second was insensitive to compensate for changes in tissue thickness, haemoglobin content and light intensity.

The system consists of a probe containing a diode that emits light in two wavelengths:

I. Red light of approximately 660 nm

II. Infra-red light of approximately 850 nm

A silicon photo detector diode is placed on the opposing surfaces of the tooth, which is connected to a microprocessor.

The probe is placed on the labial surface of the tooth crown and the sensor on the palatal surface. Ideal placement of the probe is in the middle third of the crown. If placed in the gingival third, disturbances from gingival circulation or any gingival trauma or bleeding will interfere with the readings. Incisally, less of pulp tissue is present for adequate detection of the pulse.

A number of clinical studies have proved that the pulse oximetry is an effective and objective method of evaluating dental pulp vitality. Though the surrounding insulation of the enamel and dentine are hindrances to the detection of a pulse in the pulp, it has proved to be a successful method in 70% of the clinical trials and further work is still in progress. It is also useful in cases of impact injury where the blood supply remains intact but the nerve supply is damaged.

Also current results indicate that pulpal circulation can be detected by the pulse oximeter independent of gingival circulation. Signal filtration is now employed to make it easier to reproduce pulp pulse readings.

Smaller and cheaper commercial oximeters are now available for routine clinical use in an average dental office.

22 Despite its advantages, limitations include background absorption associated with venous blood and tissue constituents, which should be differentiated. In addition to the absorption, refraction and reflection also occur as in Penumbra effect, which is seen in patients with strong tissue pulsations, where some of the light reaches the photo detector diode without passing through the tissue bed. The oxygen saturation values from the teeth routinely register lower than the readings from the patient’s finger. This may be due to the limitations of using a probe designed for other body parts, not specifically for the anatomy of a tooth.

Dual Wavelength Spectrophotometry

Dual wavelength spectrophotometry (DWLS) is a method independent of a pulsatile circulation. The presence of arterioles rather than arteries in the pulp and its rigid encapsulation by surrounding dentine and enamel make it difficult to detect a pulse in the pulp space. This method measures oxygenation changes in the capillary bed rather than in the supply vessels and hence does not depend on a pulsatile blood flow. Pulse oximetry is a method based on DWLS.

DWLS detects the presence or absence of oxygenated blood at 760 nm and 850nm. The blood volume or concentration channel (760 nm plus 850 nm) is arranged to respond linearly to the increase in light absorption. The oxygenation channel (760 nm minus 850 nm) senses the oxygenated blood because of the greater absorption at 850 nm as compared to 760 nm.

In vivo and in vitro studies were conducted to differentiate between pulp chambers that were empty, filled with oxygenated blood or fixed pulp tissue. DWLS was able to differentiate with reproducible readings between a pulp chamber of a vital and non- vital tooth in vivo.

In young children, in cases of avulsed and replanted teeth with open apices, the blood supply is regained within the first 20 days after replantation but nerve supply lags behind. Repeated spectrophotometric readings taken at the start of the replantation and continuing upto 40 days later revealed an increase in blood oxygenation levels indicating a healing process and that the pulp of the avulsed tooth was recovering. Hence endodontic treatment need not be undertaken.

Even though the instrument was not specifically designed for dental use, it was easy to use and can be developed as a pulp tester.

A major advantage is that it uses visible light that is filtered and guided to the tooth by fibreoptics. Thus unlike Laser light, added eye protection is unnecessary for the patient and the operator.

23 Still in vivo tests of this hypothesis are in progress. Influence of the gingival circulation cannot be ruled out and data on how large a mass of pulp tissue is needed for accurate readings must be determined.

The test is noninvasive and yields objective results. The instrument is small, portable, relatively inexpensive and should be suitable for use in a private dental office.

Laser Doppler Flowmetry

Laser Doppler Flowmetry (LDF) is a non-invasive, electro-optical technique, which allows the semi-quantitative recording of pulpal blood flow. The Laser Doppler technique measures blood flow in the very small blood vessels of the microvasculature.

It has been reported that Laser Doppler Flowmetry is more reliable than other pulp vitality tests and could be used as an exclusive and reliable tool to assess tooth vitality.

The technique depends on the Doppler principle whereby light from a laser diode incident on the tissue is scattered by moving RBC's and as a consequence, the frequency broadened. The frequency broadened light, together with laser light scattered from static tissue is photo detected and the resulting photocurrent processed to provide a blood flow measurement. The Doppler shifted laser light, back- scattered out of the tooth is detected by a photocell on the tooth surface. The output is proportionate to the number and velocity of the blood cells.

Over the past decade LDF technology has been used experimentally to monitor blood flow in the pulps of both, the animals and the humans. LDF has been shown to be valuable in monitoring revascularization of immature incisors following severe dental trauma.

During follow-up examination the traumatized tooth was unresponsive to traditional vitality testing during the first 6 months. However LDF indicated that revascularization had occurred much sooner.

The primary issues in pulp-vitality testing are as follows:

• A non-vital post-traumatized incisor has a better long-term prognosis if root canal therapy is completed before the necrotic pulp gets infected.

• The best outcome for the post-traumatized immature incisor is for it to revascularize and continue normal root development, including increased root wall thickness, which is not possible to assess with conventional electrical and thermal testing.

• Watching and hoping for revascularization using sensitivity testing may lead to infection in the post-trauma observation period.

24 Studies were carried out to compare LDF with conventional pulp tests, EPT (electric pulp testing) and thermal tests, in children with certain dental injuries. At the initial assessment at presentation, all tests had poor sensitivity and specificity; however at 3, 6, and 12 months, LDF was significantly better than the other tests. There was no difference between tests at the later time periods, 18 months and 2 years. It was concluded that LDF identified more vital and non-vital teeth correctly at earlier time periods following injury than conventional tests.

The limitations of this method include a too expensive device for use in a dental office. The sensor should be maintained motionless and in constant contact with the tooth for accurate readings. Also the laser beam must interact with the moving cells within the pulpal vasculature. However, it is useful in young children whose responses are unreliable and its non-invasive nature helps to promote patient co-operation and acceptance.

Local Anaesthetic

In cases where the patient cannot locate the pain and routine thermal tests have been negative, a reaction may be obtained by asking the patient to sip hot water from a cup.

The patient is instructed to hold the water first against the mandibular teeth on one side and then by tilting the head, to include the maxillary teeth. If a reaction occurs, an intraligamental (intraosseous) injection may be given to anaesthetise the suspect tooth and hot water is then again applied to the area; if there is no reaction, the pulpitic tooth has been identified.

Wooden Stick

● If a patient complains of pain on chewing and there is no evidence of periapical inflammation, a crack or an incomplete fracture of the tooth may be suspected.

● A useful diagnostic test is to ask the patient to bite on a cotton-wool roll or a wood stick.

● Biting on a cotton-wool roll or a wood stick in these cases can elicit pain, usually on release of biting pressure. Pain is often felt when the pressure is released rather than when it is applied.

● Sometimes, when the restoration is removed from a suspect tooth, the crack is seen at the base of the cavity and these deep cracks are more likely to cause symptoms.

Fibre-Optic Light for Transillumination

● A powerful light can be used for transilluminating teeth to show interproximal caries, fracture, opacity or discoloration.

25 ● Transillumination with a fibre optic light is a very simple, cheap and effective method of revealing cracks and fractures.

● However, despite the ease of use and the great diagnostic value of this technique, the concept of shining a narrow beam of strong light through teeth is not commonly utilized by dentists.

● To carry out the test, the dental light should be turned off and the fibre-optic light placed against the tooth at the gingival margin with the beam directed through the tooth. If the crown of the tooth is fractured, the light will pass through the tooth until it strikes the stain lying in the fracture line; the tooth beyond the fracture will appear darker.

● Transillumination of the teeth with a fibre optic light is shone from numerous different directions.

● The principle of transillumination of teeth works because the light beam is deflected once it reaches a crack or fracture which then appears as a dark line. Only the side of the tooth from which the light is being shone will be illuminated by the light and the contralateral side of the crack or fracture will remain dark. This procedure relies on contrast and therefore all extraneous light must be eliminated from the area which can be easily achieved by turning off the dental operating light and any other bright lights within the room.

Cutting a Test Cavity

When other tests have given an indeterminate result, a test cavity may be cut in a tooth which is believed to be pulpless. In the author’s opinion, this test can be unreliable as the patient may give a positive response although the pulp is necrotic. This is because nerve tissues can continue to conduct impulses for some time in the absence of a blood supply.

TREATMENT PLANNING

Having taken the case history and carried out the relevant diagnostic tests, the patient’s treatment is then planned. The type of treatment or therapy chosen must take into account the patient’s medical condition and general dental state.

DIFFERENTIAL DIAGNOSIS OF PAIN OF PULPITIS

● Pain symptoms often challenge the clinician’s diagnostic abilities. Generally, pain is conceptualized by two components: perception of pain, influenced by anesthesia, and reaction to pain, such as fear and depression, which is influenced by drugs and emotion. These emotional states vary from person to person and can exaggerate the perception of

26 pain. Frequently it is patient confusion in perception of their pain that lead to difficulties in diagnosis.

● In order to accurately diagnose the etiology of pain, the clinician must first understand that pain can be of odontogenic or systemic origin (non-odontogenic).

● Pain sometimes originates from other areas and radiates to the jaw, thus being perceived as tooth pain, most commonly from the temporomandibular joint, ear, and even occasionally cardiac problems.

● Evaluation of the dental history, including a history of pain in the same tooth before the present pain experience, the nature of response to various stimulus and the longevity of the pain are all important consideration in establishing a correct diagnosis.

● Accurate assessment of a patient history can frequently establish a defined differential diagnostic strategy prior to the clinical examination. A through clinical exam with the differential diagnostic strategy in mind can expedite the process.

● The development of a differential diagnosis must include consideration of both odontogenic and non-odontogenic forms of pain.

● The rationale for developing a differential diagnosis is obvious, but its application is challenging. The vast majority of dental pain emergencies consist of disorders with relatively little diagnostic challenge (eg. pulpal necrosis with acute apical abscess). This dominant pattern of odontogenic pain disorders may lead to clinical shortcuts in which a differential diagnosis is never established. Under these conditions, the patient presenting with a rare but very real form of nonodontogenic pain may not receive appropriate therapy due to a misdiagnosis.

● Thus, the challenge is to maintain vigilance in evaluating patients and developing differential diagnoses.

A list of differential diagnosis will include:

Odontogenic:

● Dentinal Hypersensitivity;

● Traumatic occlusion secondary to a new restoration;

● Periradicular or periapical pain arising from potential sequelae of pulp diseases, e.g., acute periapical periodontitis and acut periapical abscess;

● Referred pain from a tooth in the opposing arch;

27 ● Dry socket (Localised Alveolar Osteitis);

● Barodontalgia from high altitudes.

Non-Odontogenic:

Musculoskeletal:

Myofascial pain/Temporomandibular joint pain (TMJ) Bruxism

Neuropathic:

Trigeminal neuralgia Atypical odontalgia Glossopharyngeal neuralgia

Neurovascular:

Migraine Cluster headaches

Inflammatory:

Allergic sinusitis Bacterial sinusitis Otitis media and/or mastoiditis

Maxillary sinusitis is the most common extraoral source of tooth pain. All or most teeth in the upper arch may become sensitive secondary to sinusitis.

Systemic disorders:

Cardiac pain: Angina pectoris: Reffered pain Herpes zoster Sickle cell anemia

Neoplastic disease:

Cancers of the jaw,etc.

Psychogenic origin:

Munchausen’s Syndrome

28 Salivary gland disorders

Sjögren’s syndrome Systemic lupus erythematosus Sialolithiasis

29