What further details do you need to know about the patient’s complaint?

The first step in the management of any patient is an accurate history. This informs what aspects of the clinical examination are most relevant, which in turn will inform which special investigations are most appropriate.

If it is an endodontic problem, it will help you to work out whether it is a pulpal and/or periapical problem. It is also necessary to determine what type of dental treatment (if any) has been recently carried out in the lower and upper right quadrants.

Typical questions that should be asked include:

• Where is the pain? Can the symptoms be localised to a specific tooth or region, or are they diffuse (poorly localised)?
• When and how did the symptoms start, and has the character of these symptoms altered over this period?
• How would you describe the symptoms – dull, sharp or throbbing?
• When the symptoms are at their worst, how severe are the symptoms on a scale of 1–10?
• Once triggered, how long do the symptoms last for: seconds, minutes or hours?
• How are the symptoms affected by cold, hot or chewing?
• Does anything trigger or worsen the symptoms?
• Does anything relieve the symptoms (for example, analgesics)?
• Can the symptoms be spontaneous and/or have they woken you up during the night?
• Have you had any recent dental treatment on this side of your mouth, and do you remember what type of treatment was carried out?

From the answers to these questions, you find out that the patient has had an occasional low‐grade intermittent dull ache for approximately six months, localised to the mandibular right first molar. She has had two acute episodes of pain (flare‐ups) in this time that eventually subsided after she took a course of antibiotics prescribed by her previous dentist. The patient noticed that the pain was more common when she was run‐down or tired. She occasionally took non‐steroidal anti‐inflammatory analgesics when the pain became too uncomfortable, which helped with her symptoms. The patient advised you that when she initially developed her symptoms from this tooth, she occasionally woke up in the middle of the night with a dull, throbbing pain localised to this tooth.

What clinical investigations would be most appropriate?

• Assessment of the structural and strategic value
• Palpation
• Presence of a sinus tract
• Mobility
• Percussion
• Periodontal probing

The clinical examination revealed that the LR6 was slightly tender to percussion and buccal palpation only. The tooth was not mobile, and examination of the adjacent mucosa did not reveal a sinus tract. There were no periodontal probing depths greater than 2 mm. The margins of the existing restoration appeared to be sound. Examination of the upper right quadrant did not reveal any abnormalities.

What special investigations would you carry out?

• Sensitivity (vitality) test: Cold, heat and/or electric pulp testing should be carried out to assess the pulpal status. It is essential to test neighbouring and contra‐lateral teeth for comparison (controls). The response can be described as immediate/delayed, normal/exaggerated/reduced/no response, and reference made to whether it reproduced the patient’s symptoms.
• Radiographs: A periapical and/or bitewing radiograph and cone beam computed tomography (CBCT) scan can reveal clues to the status of the pulp and periradicular tissues (Figures 4.4.1 and 4.4.2a–d). Features that may indicate an unhealthy pulp include dystrophic calcification, gross caries and restorations in close proximity to the pulp. Infection of the root canal system may be inferred from widening of the periodontal ligament, periapical radiolucency and previous (inadequate) root canal treatment.

The LR6 did not respond to electric or cold sensitivity testing; the LR5, LR7, UR5, UR6 and UR7 responded within normal limits.

What did the radiograph and cone beam computed tomography scan reveal about the lower right first molar?

• Minimal horizontal bone loss.
• Secondary caries.
• Calcification of the pulp and canals.
• Periapical radiolucency associated with the mesial and distal roots.
• Isthmus between mesial canals (Figure 4.4.2a, arrow).
• Wide, elliptical cross‐section of distal canal (Figure 4.4.2c, arrow).

What is the diagnosis?

A diagnosis of symptomatic periapical periodontitis associated with an infected necrotic root canal system was reached for the LR6.

The potential treatment options that should be discussed with the patient are:

• Root canal treatment
• Extraction
• Leave alone

Treatment decisions are informed by the particular array of prognostic factors and treatment complexities. In this case, root canal treatment and subsequent restoration of the tooth, if adequately executed, is very likely to result in periapical healing and tooth survival. The treatment is of moderate complexity owing to the root canal anatomy (calcification, curvatures, and ramifications) and deep distal restorative margin. In light of this, root canal treatment is the preferred option as the tooth appears to have a good overall prognosis, and is of functional and strategic value. Extraction would also eliminate the patient’s symptoms; however, she would also lose a functionally strategic tooth, and the resulting unopposed maxillary first molar tooth would become non‐functional and may over‐erupt. You may also want to briefly discuss with the patient the costs and risks of replacement options for this tooth.

Although the patient could leave the tooth alone (i.e. have no treatment), this is not advisable as her existing symptoms will continue as will her occasional flare‐ups, for which repeated courses of antibiotics are not appropriate. In addition, she may eventually suffer from an acute apical abscess that, in severe cases, may result in pyrexia, malaise and even obstruction of her airway. Similarly, a prolonged delay in initiating treatment may result in a reduced endodontic prognosis, as well as risk further structural deterioration of the tooth.

Endodontic treatment was carried out in a single visit under dental dam. The existing restoration and carious tissue were removed, and the restorability was reassessed. As the tooth was deemed restorable, a pre‐endodontic restoration was placed prior to access cavity preparation. On accessing the pulp, no cracks or fracture lines were detected. The working length was determined using an apex locator and confirmed with a radiograph. Mechanical preparation was carried out, with frequent irrigation with sodium hypochlorite throughout the procedure. The canals were subsequently obturated with gutta percha and root canal sealer using a warm vertical compaction technique. The access cavity was restored with a composite restoration.

What was the most likely cause of this endodontic problem?

The mouth contains an abundance of microbial species, most of which are opportunistic pathogens. If there is an interruption in the integrity of the protective enamel surface, such as caries or a crack, this can allow microbes to colonise the dentine, and ultimately affect the pulp. Unfortunately, the pulp has a limited capacity to protect itself against an advancing microbial front, particularly where it is sustained by nutrients and additional microbes from the oral environment.