Summary

Endodontic disease frequently presents with sudden pain and swelling that leads patients to seek emergency dental care. Management of infective endodontic emergencies represent more than 90% of total dental emergencies with most occurring before root canal treatment and which require immediate pulpal and periapical diagnoses based on the patient’s symptoms, especially pain, and the dental and medical histories. Irreversible pulpitis (vital pulp) and acute apical abscess (nonvital pulp), with or without swelling, are the two most frequently diagnosed diseases, each requiring very different management. On the other hand, endodontic infections are polymicrobial and, in some cases, prescription of antibiotics may be indicated. Since antibiotic-resistant bacterial strains are a global concern, the use of antibiotics to deal with endodontic infections should be based on scientific evidence. In case of discrete and localised swelling, the primary aim is to achieve drainage without antibiotics. Adjunctive antibiotic treatment may be necessary to prevent the spread of infection, in acute apical abscesses with systemic involvement, and in progressive and persistent infections. Antibiotic prophylaxis should be considered in patients with compromised immunity or in patients with a localised congenital or acquired altered defense capacity, such as patients with infective endocarditis, prosthetic cardiac valves, or recent prosthetic joint replacement.

28.1 Endodontic Emergencies

The genuine dental emergency can be defined as the situation that makes the patient request an unscheduled and urgent dental appointment for diagnosis and treatment [1]. The three characteristics of a true dental emergency are: 1) interruption of the patient’s normal daily activities (eating, sleep, work); 2) the request for assistance takes place shortly after the onset of the symptoms; and 3) analgesics, if it is a painful event, have not controlled the pain. The major symptoms that lead the patients to request emergency dental care are pain and swelling of the orofacial area with pulpal and periapical diseases being the most frequent cause of these symptoms [2].

The endodontic emergency can be defined as the clinical situation characterised by dental pain, with or without swelling, caused by pulp and/or periapical pathosis, which causes the patient to request immediate diagnosis and treatment. Endodontic emergencies represent almost 90% of all dental emergencies [1]. The frequency of endodontic emergencies correlates with the age of the patients up to 40 years, due to the increasingly prolonged exposure of teeth to caries and trauma as they get older [3].

Endodontic emergencies can be classified according to the moment in which they occur [2]. Before treatment, the cause can be reversible or irreversible pulpitis, acute periapical abscess, or cracked/split teeth. Patients under treatment can request urgent care after the first appointment of root canal treatment because of symptomatic apical periodontitis (flare-up) or tooth cracks/splits. After root canal treatment, patients can also request urgent care because of symptomatic apical periodontitis (flare-up) as a consequence of a high restoration, root canal overfilling, root fracture, or in most cases, persistent apical periodontitis [4].

The vast majority of endodontic emergencies occur before root canal treatment (95%). The most frequently affected teeth are molars (75%) with mandibular teeth (57%) causing emergencies more frequently than maxillary teeth (44%). The most frequently diagnosed condition is symptomatic apical periodontitis (45%) [3].

28.1.1 Diagnosis and Treatment Planning in Endodontic Emergencies

Considering that the histological state of the pulp cannot be assessed clinically, the diagnosis should be made based on the patient’s symptoms, especially pain, and the medical history and the signs that are noted during the clinical examination. For the correct diagnosis, it is essential to consider the patient’s main complaint, pain and its characteristics, through active listening. Finding out the location of the pain and when the pain was first noticed is very important. Characteristics of pain (under what circumstances does the pain occur, does anything relieve it) are also important. Associated tenderness or swelling should be identified. Previous dental history, such as recent restorative treatment, periodontal treatment, or a history of trauma to the teeth, must be investigated. Periapical radiographs taken with a paralleling technique, sensitivity pulp tests, and periodontal probing are the three main diagnostic aids [4]. Cone-beam computed tomography (CBCT) can help in some situations. Once the subjective history has been recorded, the main complaint analysed, and the clinical examination completed, the diagnosis can be made and any active treatment planned, either to immediately relieve the patient’s pain or, if necessary, to complete root canal treatment at the same time.

The two situations that are most frequently diagnosed are irreversible pulpitis (vital pulp) and acute apical abscess (nonvital pulp), each requiring different management. However, reversible pulpitis can also cause pain that leads patients to request emergency care.

28.1.2 Emergency Treatment of Symptomatic Reversible Pulpitis

Reversible pulpitis is characterised by a sharp pain experienced immediately after a stimulus, such as cold, heat, or sweet, is applied and goes away within a couple of seconds following the removal of the stimulus. It is a clinical diagnosis based on subjective and objective findings indicating that the inflammation should resolve and the pulp return to normal following appropriate treatment [5]. The affected tooth may give an exaggerated response to pulpal sensitivity tests. The periapical radiograph reveals a normal appearance, and there is no apparent widening of the periodontal ligament, except when occlusal trauma is present. In that case, the tooth can also be sensitive to percussion.

The pathogenesis of reversible pulpitis lies in a mild or moderate pulp and/or periapical inflammation caused by irritants such as carious lesions, operative procedures, dental injuries, restorative materials, orthodontic movements, or tooth whitening [6].

Pain caused by reversible pulpitis indicates an inflamed pulp that can be treated without the removal of the pulp tissue. When the aetiologic factor is removed, and in the absence of infection, the inflammatory process becomes a reparative process. In most cases, the following treatment may be all that is necessary:

• Place a sedative dressing in the cavity (such as calcium hydroxide or calcium silicate based cement followed by coronal restoration) after removal of deep caries,
• Apply a fluoride varnish or a dentine bonding resin to sensitive dentine and prescribe a desensitizing toothpaste [6].

The inflammatory process may resolve in a similar fashion to that of other connective tissues; a layer of reparative dentine may be formed as protection from further injury [4].

28.1.3 Emergency Treatment of Symptomatic Irreversible Pulpitis

Symptomatic irreversible pulpitis refers to the pulpal state that implies the presence of a severe inflammatory process that will not heal and that, if left untreated, will result in pulpal necrosis followed by apical periodontitis [5]. Subjective and objective findings indicate that the vital inflamed pulp is incapable of healing [7]. Symptomatic irreversible pulpitis is a frequent cause of endodontic emergencies. Pulpectomy or extraction (if nonrestorable) is required to alleviate the symptoms and prevent apical periodontitis.

The patient may not be able to identify exactly the causative tooth because the pain is not well localised and, sometimes, cannot be identified as being from a mandibular or maxillary tooth. At first, pain is caused by stimuli (cold, heat, osmotic) and does not stop when those stimuli cease. Then the pain becomes spontaneous. Characteristics may include sharp pain upon thermal stimulus, lingering pain (often 30 seconds or longer after stimulus removal), spontaneity (unprovoked pain), and referred pain [5]. There is no percussion sensitivity before periapical involvement, but the tooth becomes tender to percussion once inflammation has spread to the periodontal ligament.

Emergency treatment of symptomatic irreversible pulpitis requires access to the pulp chamber followed by removal of inflamed pulp tissue. Next, cleaning and shaping of the root canal system should be performed. Sodium hypochlorite has proven to be one of the most effective disinfectant agents and should be used to minimise the residual bacterial load within root canals. The objective is to remove completely the irritating pulp tissue and provide the patient with pain relief. A calcium hydroxide inter-appointment medicament placed in the coronal and middle third of the root canals will reduce remaining bacteria and inflammation (and thereby reduce pain) and prevent contamination between appointments [8]. Finally, a temporary filling should be placed to avoid coronal leakage during the period between appointments, and an appropriate nonsteroidal anti-inflammatory drug may be prescribed. Antibiotics are not indicated in the treatment of asymptomatic irreversible pulpitis [9]. Corticosteroid dressings should be used carefully as there is evidence that suppression of an inflammatory response by steroids allows bacteria to enter the bloodstream with ease [10].

The management of pain in patients with irreversible pulpitis is not always easy because of the often acutely inflamed pulp, particularly treating mandibular teeth with irreversible pulpitis (hot tooth). Patients with irreversible pulpitis have allodynia and hyperalgesia, with reduced mechanical pain thresholds [11]. Mepivacaine with epinephrine has been demonstrated to provide the best pulpal anaesthesia for inferior alveolar nerve blocks (IANB) for teeth with irreversible pulpitis, compared to prilocaine, articaine, bupivacaine and lidocaine [12]. The intake of ibuprofen ≥400 mg 1 hour before the emergency treatment has been reported to significantly improve IANB success [13, 14]. Supplementary analgesia can be obtained with additional infiltration anaesthesia, such as long-buccal, lingual, and palatal; intraligamentary injection; intra-osseous injection; intrapulpal analgesia; or inhalational sedation with local analgesia. If, using these techniques, anaesthesia of the tooth to be treated is not achieved, it is advisable to use intraligamental, intraosseous, or intrapulpal injections. The use of Gow-Gates and Vazirani-Akinosi techniques have been proposed for pulpal anaesthesia for mandibular posterior teeth in patients presenting with symptomatic irreversible pulpitis, but both injections would require supplemental anaesthesia [15, 16].

28.1.4 Emergency Treatment of Acute Periapical Abscess

Pulpal infection and necrosis causes apical periodontitis of endodontic origin. Acute periapical abscess is characterised by rapid onset, spontaneous pain, tenderness of the tooth to pressure, pus formation, and swelling of associated tissues [7]. In the early stages, there may be no radiographic signs of bone destruction and the patient often experiences malaise, fever, and lymphadenopathy. The characteristic symptoms of the acute periapical abscess are (Figure 28.1):

• evident soft-tissue swelling,
• extremely tender tooth which could be extruded from the socket, and
• increased mobility.

The differential diagnosis should be made to exclude a lateral periodontal abscess by testing the pulp status. If it is vital, then the cause may be periodontal in origin [4].

Obtaining adequate drainage to relieve pressure should be the immediate objective. In general, opening up the pulp chamber achieves this goal. Because the tooth is extremely sensitive and anaesthesia usually takes time (as in the case of irreversible pulpitis, complementary techniques can be used), the turbine handpiece should be used with a small diamond bur to minimise operative trauma. To create drainage, the apical foramen can be explored with a small file (size 08 or 10). If possible, the pus can be aspirated through the root canal.

As indicated by the Latin aphorism ‘Ubi pus, ibi evacua’, if intraoral soft-tissue swelling is present, it should be incised to establish drainage. The presence of cellulitis can prevent or reduce drainage. In these cases, prescription of antibiotics should be considered and in severe cases medical advice sought. An acute periapical abscess with systemic involvement and affecting immune-compromised patients are indications for systemic antibiotic treatment [9]. Although surgery is contraindicated in inflamed tissues, abscess drainage is the exception. The presence of a fluctuating purulent collection in soft tissues related to the affected tooth is an indication for urgent surgical drainage. Surface analgesia, with ethyl chloride or topical lignocaine, can be applied. Without drainage, the infection cannot be controlled and antibiotics will not have the desired effect. No. 11 or 15 scalpel blades can be used to incise swellings. A large diameter needle and a disposable syringe must be used to aspirate the abscess. If necessary, the aspirate can be sent for bacteriological examination. If it is considered necessary to insert a drain, a quarter inch or half-inch selvedge gauze can be used. The patient should stay in the chair until the drainage stops which, sometimes, can mean waiting 30 minutes or more. If drainage by extraoral incision is necessary, it is essential to refer the patient to an oral surgeon for this particular procedure [4].

After draining the abscess, the tooth should be isolated with a rubber dam to continue the treatment. Organic residues in the pulp chamber should be removed by irrigating with sterile saline. Then, the root canals must be mechanically debrided using files, irrigating profusely with sterile saline to reduce the incidence and intensity of postoperative pain. Cryotherapy, controlled irrigation with cold saline, reduced the incidence of postoperative pain and the need for medication in patients presenting with a diagnosis of necrotic pulp and symptomatic apical periodontitis [17]. The root canals should be dried with paper points, and calcium hydroxide placed as an intracanal medicament [4]. A dry sterile cotton wool should be placed on the floor of the pulp chamber and a temporary filling placed in the access cavity. The two-visit protocol by using an interappointment medicament has been reported to result in an improved microbiological status within the root canal system when compared with the one-visit protocol [18]. Moreover, the benefit of a single-visit treatment, in terms of time and convenience, for both patient and dentist has the drawback of a greater frequency of late postoperative pain and painkiller use [19]. Ibuprofen 600 mg or ibuprofen 600 mg with acetaminophen 1000 mg is effective in attenuating postoperative endodontic pain in patients without contraindication [20].

There are two especially life-threating cases of cervical-facial cellulitis, as a consequence of symptomatic apical periodontitis, that need urgent medical attention and that, if left untreated, can even cause death. The first is Ludwig’s angina, a bilateral infection of the submandibular, sublingual, and submylohyoid spaces, affecting deep neck planes. The teeth involved are usually the second or third mandibular molar tooth. Acute suppurated apical periodontitis evolves rapidly, spreading through the aforementioned spaces, and may cause mediastinitis compromising the airways [21]. The patient has signs of deep neck infections: fever, swelling of the floor of the mouth, swelling below the inferior border of the mandible, asymmetric bulging of the pharyngeal walls and trismus or pain out of proportion to the amount of swelling [22]. In addition to drainage through the access cavity, early antibiotic treatment should be broad spectrum to cover gram-positive and gram-negative bacteria as well as anaerobes, and intravenous steroids may be needed to reduce soft tissue swelling and oedema, decreasing the probability for the need of a surgical airway. This treatment should be performed in a hospital under the supervision of maxillofacial surgeons.

The other case of severe odontogenic infection needing emergency attention is post-septal orbital cellulitis. This serious complication affects the muscles and fat located inside the orbit and may lead to vision loss and even death when the infection extends intracranially, causing cavernous sinus thrombosis and/or a brain abscess [23]. The causative teeth may be canine, premolars, and first maxillary molars. The infection starts as an acute abscess but rapidly spreads to the maxillary sinus and enters the orbit through the orbital floor. Typical symptoms are eyelid swelling, with or without erythema; ophthalmoplegia; pain with eye movement; and/or proptosis [24]. The process must be quickly diagnosed and, after drainage, the patient referred to the hospital. As in the case of Ludwig’s angina, systemic antibiotics are indicated. The management of this serious complication should be performed by maxillofacial surgeons.

28.1.5 Cracked Tooth

An endodontic emergency due to a cracked tooth occurs when the crack penetrates deeply into the dentine and reaches the pulp, causing pulpitis. Along with severe pain with chewing, the patient has sensitivity to hot and cold fluids and acute localised pulp pain. Generally, intraoral examination with the naked eye is not able to detect the crack. Sometimes, the pressure of the explorer separates the fragments of the tooth and allows it to be seen (Figure 28.2). Periapical radiographic images will reveal the crack only if it runs in a buccolingual plane. A fibre-optic light may help to reveal the position of the fracture. However, cone beam computerized tomography (CBCT) is the main diagnostic aid to detect the crack. The use of an operating microscope (6–8× magnification or greater) and shadow-free co-axial illumination that is coincident with the dentist’s viewing axes allows for identification of the crack [25]. Its localization and extent are the two essential factors to decide whether the tooth can be saved [4].

28.1.6 Traumatic Injuries of the Teeth

Traumatic injuries of the teeth represent a significant percentage of endodontic emergencies. The incidence of traumatic dental injuries is 1–3%, and the prevalence is steady at 20–30% [26]. Proper diagnosis, treatment planning, and follow-up are important for improving a favourable outcome, having a large influence on prognosis. For the emergency treatment of dental trauma, the clinical guidelines developed by the International Association of Dental Traumatology (IADT) must be followed [27].