From a psychological perspective

Many patients are nervous or anxious prior to endodontic treatment of acute pain. The expectation of pain during or following treatment may be very strong particularly in highly anxious patients, and the pain may be triggered simply by touching the suspected tooth [3].

The increased reactivity derive partly from neurogenic inflammation (see chapter 1), leading to increased sensitivity and activity in otherwise inactive neurons, and is partly psychological in nature [4]. From a psychological perspective, the initial challenge for the dentist is to get the patient´s confidence, because the patient's assessment of the dentist's skill will be reflected in how painless the treatment per se can be performed.

Treatment of acute pain should include strategies based on information, distraction, relaxation or possibly hypnosis [3].

Anesthetic considerations

Local anaesthesia can be administrated as infiltration or nerve block. In the maxilla, infiltrations are usually preferred because the bone is fairly porous and the liquid can infiltrate the bone.

In the mandible, the outer layer of cortical bone is thicker and a nerve block should be the first choice. Labial or lingual infiltrations alone are not effective for pulpal anesthesia in mandibular teeth [5].

Sufficient local anesthesia is essential, but can sometimes be difficult to achieve. It has been stated that for an inferior nerve block a single carpule will be sub-optimal in 30 - 80 % of cases with acute irreversible pulpitis [6]. Notably, the lack of pain relief in some patients may be due to prolonged onset. The onset of pulpal anesthesia usually occurs 10 - 15 min following inferior alveolar nerve block injection. However, in 20 - 30 % of the patients the time from the injection to pain relief may be longer, and in 10 % it may take up to 30 min before full effect is obtained [7].

In the literature there is no consensus for the beneficial effect of repeating a mandibular injection (in cases of absence of impact) to increase the volume of anesthetic liquid. Interestingly, lack of precision for placing the needle seems also to be of minor importance (within certain limits) and not evaluated to be essential for the effect [8]. However, there may be a few exception. The nervus mylohyoideus sometimes branches to the mandibular molars [9]. In order to include this within the anesthetic strategy, the needle should be placed either higher on the ramus or supplemented with an injection in the floor of the mouth.

A mandibular buccal infiltration using articaine (4 %) has been shown to provide an additive effect to mandibular block [10]. However, except for this there is no robust evidence in the literature to suggest that any of the routinely used anesthetics has a general distinguishing anesthetic effect.

Injection in acutely inflamed tissue should be avoided to prevent spreading of infection, and presence of inflammation decreases local anesthetic efficacy [11].

Preoperative pain medication with non-steroidal anti-inflammatory medication (NSAIDs) 1 hour before administrating anesthetics has been shown to increase the efficacy in patient with acute pulp inflammation [12]. If the sensibility test after prolonged observation still reveals sensitivity, it is advised to proceed with supplemental techniques, such as intraligamentary or intrapulpal injection (box 1 and 2).

Diagnostic considerations

When patients arrive with pain, the pain profile may not correspond with the actual presence of pulp inflammation [13]. Based on subjective and objective findings pulpitis is divided into two clinical diagnoses: irreversible pulpitis and reversible pulpitis. In reversible pulpitis a local inflammation should be able to resolve and the pulp return to normal following appropriate management of the cause of the condition.

In irreversible pulpitis, on the other hand, the dental pulp is severely inflamed and damaged beyond repair. In the acute phase it is associated with spontaneous burst of intense pain that tend to linger for minutes or more.

The clinical diagnosis is mainly based on anamnesis and clinical symptoms such as degree/characteristic of pain and signs associated with pulpal inflammation. The needed diagnostic considerations are outlined in Table 1.

Treatment principles

Caries is the most frequent reason why dentists perform root canal treatment [14]. There is a correlation between the depth of caries lesion and the degree of inflammation in the pulp [15]. It seems to be crucial for the prognosis of preserving pulp vitality if caries excavation can be performed without pulp communication [16].

If the pulp is exposed due to a deep caries lesion, pulpotomy or pulpectomy, should be performed and this is most reliable treatment to obtain pain relief [17].

Prescribing of systemic antibiotics for symptomatic irreversible pulpitis will not provide any pain relief [18]. The infection is located inside the hard dental tissues or in superficial parts of the necrotized pulp tissue, where antibiotics from the bloodstream cannot reach it.

Pulpotomy

The aim of a pulpotomy is to remove the inflamed coronal pulp tissue from the pulp chamber without penetrating into the radicular pulp tissue. The pain relieving effect is most probably due to a removal of the source of inflammation and drainage with a concomitant reduction in local tissue pressure and concentration of inflammatory mediators. Pulpotomy leads to pain relief in 90 % of treated cases [17, 19.

The use of a diamond drill with a non-cutting tip is very suitable to remove the roof of the pulp chamber after access (Figure 2), and a slowly rotating bur is used to remove the coronal pulp tissue.

Irrigate with plenty of NaOCl to cleanse the area and stop the bleeding. If bleeding still occurs use an aqueous mixture of calciumhydroxide or a pellet of 3 % hydrogen peroxide on the canal orifices until the bleeding stops.

Using local sedative or antibacterial dressings, such as eugenol, camphorated phenol or steroids have previously been used and regarded as crucial for pain relief but this effect has not been shown in comparative studies [17].

The thickness of the temporary restoration is of importance when multiple endodontic visits are performed. The temporary filling should at least be 4 mm thick to maintain a bacteria tight sealing [20].

It is important that the patient is informed that the dental treatment is not finished and that a new appointment is needed to complete the treatment and ensure that the pain does not reappear.

Pulpectomy

Clinically it is difficult to determine the extent of the pulpal inflammation. Therefore, performance of pulpectomy and complete removal of the pulp tissue is 'standard of care' treatment of irreversible pulpitis, if there is no time restrictions [16].

It is fundamental that the pulpectomy is performed under aseptic conditions. As soon as the pulp chamber is exposed, rubber dam should be used for isolating the tooth from oral and salivary contamination. Introducing microorganisms to the root canal increase the risk of postoperative pain and reduce the prognosis for the treatment.

After the chemomechanical treatment of the root canal system the root filling can either be performed during the same appointment or after an inter-appointment dressing with calciumhydroxide.

Considerations of local or systemic spreading of infection

Apical periodontitis is an inflammatory disease in the periradicular tissue of the tooth caused by microorganisms (mainly bacteria) infecting the necrotic root canal system.

The intensity of inflammatory response will depend on the quantitative (number) and qualitative (virulence) nature of the microorganisms and the host inflammatory response. A swelling within the soft tissue may appear, that can be either localized (abscess) or diffuse (cellulitis).

In most cases apical periodontitis is related to a specific tooth and there is no signs of spreading of the infection. In rare cases, however, the infection may spread through the connective tissue and result in life-threatening complications such as Ludwig's angina or brain abscess.

Treatment principles

The elimination of local microbial factors by chemomechanical debridement of the root canal system should be performed if there is enough time [16].

Caries and fillings at risk of leakage should be removed and the root canal treatment should be performed under aseptic conditions using rubberdam to avoid additional microbes entering the root canal system.

It is possible to create drainage from the periradicular tissues through the root canals and to reduce localized tissue pressure by exploring the apical foramen with a thin file (size 10 - 15). The root canal system should be filled with calciumhydroxide and the access cavity sealed with a temporary filling.

The first-line treatment for teeth with symptomatic apical periodontitis should be establishment of adequate drainage either through the pulp chamber (Figure 3), by incision and drainage or by extraction. Drainage facilitates the evacuation of pus, allow decompression and consequently provide pain relief. The pulp chamber should not be left open for drainage. The microbial flora in the canal will change making disinfection more difficult and, furthermore, it may increase the risk of subsequent flare-up [21].

When a mature, fluctuating abscess is localized, it should be incised and drained through the mucosa by a minor surgical procedure. In most cases, a drain placed in the incision for 24 - 48 hours will allow for adequate drainage.

In situations with limited time, performing an access cavity preparation, providing an opening to the pulp chamber and placing a temporary filling, gives pain relief for a substantial proportion of patients [16]. However, this strategy should not be attempted in patients with swelling and or pus formation.

Extraction of the diseased tooth is the simplest and most effective pain relieving method as it removes the source of infection and drains the pus and should always be considered in cases with extensive loss of coronal tooth substance and questionable restorability.

Antibiotics and painkillers

Prescription of antibiotics should always be preceded by a benefit risk analysis on an individual basis. Antibiotics are usually not indicated in cases of a localized abscess and its role in pain reduction is limited [22]. The pain associated with acute apical periodontitis is best treated with analgesics. No other known medicaments have the potential to reduce the pain [23]. NSAIDs or, if contraindicated, paracetamol should be prescribed [24]. NSAIDs and paracetamol can be used effectively in combination in a two-hour dosing schedule. If this does not provide sufficient pain relief opioid analgesics may be required.

Systemic antibiotics have a definite role as a supplement to clinical procedures in cases where drainage is not possible and there is evidence of spreading infection (trismus, cellulitis, lymph node involvement, pain during swallowing) or systemic involvement, where the general health is affected e.g. the patient being feverish (malaise) or if a swelling rapidly increases.

The choice of antibiotic is influenced preliminary by the stage of infection development and the ability of the patient to take the antibiotic - medical conditions or allergy.

First-line antibiotics is phenoxymethylpenicillin (PcV) and if insufficient metronidazol should be added. In case of allergy clindamycin is the first choice of treatment [25]

With appropriate acute treatment symptom relief can be expected within two-three days and after five days a high proportion of teeth will be asymptomatic [26].

Diagnostic considerations

Endodontic-periodontal lesions may be a diagnostic challenge to the clinician [30], but it is of vital importance to make a correct diagnosis so that the appropriate treatment can be provided. It is important to diagnose potential contributing factors such as root fractures, root resorptions, perforations, and dental malformations that may play important roles in the development, progression and prognosis of endodontic-periodontal lesions. The recognition of pulp vitality is essential for differential diagnosis and treatment decision related to inflammatory lesions in the marginal and apical periodontium. Acute exacerbation from a periapical abscess may drain/fistulate through the periodontal ligament into the gingival sulcus (Figure 4). This condition can mimic the presence of a periodontal pocket or abscess

Treatment principles

Periodontal lesions of endodontic origin heal following endodontic treatments. However, the prognosis of the treatment is less favourable if the patient suffers from a general marginal periodontal problem.

The initial management of a periodontal abscess involves pain relief and control of the infection. This can be encouraged by gentle irrigation with saline and scaling of the pocket whilst massaging the soft tissues. With a history of recurrent periodontal abscesses and significantly compromised periodontal support extraction of the tooth should be considered.

Primary periodontal disease with secondary endodontic involvement and true combined endodontic-periodontal diseases require both endodontic and periodontal therapies.

A summary of the different conditions is seen in Table 2.

Diagnostic considerations

The indications for third molar surgery have been discussed throughout the years and have been a topic of controversy. There is not enough evidence to support prophylactic removal of third molars [31], and the consensus today is that third molars should be removed only if they repeatedly cause problems or if there is a risk of future damage to neighbouring teeth.

This may occur when the third molar lack space in the mandible during eruption, and is a common developmental problem. The third molar may be partially or completely impacted against adjacent tooth, the mandible ramus and surrounding soft tissue. If bacteria gain access into the follicular space through an opening in the overlying gingiva, an inflammation in the surrounding tissue, pericoronitis, will develop.

Symptoms involved in pericoronitis are pain, swelling of soft tissue and alveolar osteitis.

Treatment principles in cases of symptoms

Local treatment, such as rinsing with sodium chloride in the soft tissue pocket, instructions of improved brushing technique and mouth rinsing with an antibacterial medium, is the first step, and may slow down the infection. Grinding on the opposing tooth may be considered, if the patient experience pain when biting or if the opposing tooth will traumatize the swollen operculum further. If the condition gets worse, the patient may develop trismus, lymph node involvement, pain during swallowing and feel generally unwell with fever.

If an abscess develops, within a fibrin capsule, it has to be drained by an incision.

Recurrent pericoronitis is an indication for third molar surgery, but it is important to treat the infection before the surgical removal, to reduce the risk for spreading of the bacterial infection.

Antibiotics and painkillers

Antibiotics should be considered where drainage is not possible, there is evidence of spreading infection or systemic involvement. First choice of antibiotics is phenoxymethylpenicillin (PcV) and if that is not enough metronidazol can be added. In case of allergy clindamycin is the first choice but can also be used when a broader spectrum antibiotic is necessary.

NSAID/paracetamol should be prescribed separately or in combination. If the patient does not show improvement NSAID/paracetamol in combination with opioid could be used.

In case of suspected diffuse spreading into deeper spatiums (flegmone, Ludwigs angina), the patient needs to be treated in the hospital. Signs of this condition are swollen mouth floor, trismus, dysfagi and dyspné with high frequent breathing (stridor) and fever. The patient must immediately be referred to the hospital for treatment where i.v. antibiotics and drainage of the abscess will be performed. In some cases the condition can be life threatening.