Diagnosis and treatment planning

What was the diagnosis for molar 46?

A diagnosis of chronic periapical periodontitis with suppuration (i.e. a sinus tract), associated with a previous root canal treatment, was reached for the 46.

Why was the patient virtually symptom free?

Once a sinus tract forms, the associated tooth generally becomes asymptomatic. The sinus tract represents a pathway for drainage of the infection. Therefore, as the suppuration is not confined to an enclosed compartment within the bone, no pressure accumulates and there is, consequently, little swelling and pain. Sinus tracts follow the path of least resistance into the oral cavity (or, exceptionally, extraorally) and when associated with mandibular teeth, invariably drain buccally rather than lingually (as was the case with this patient). Antibiotics are generally not a necessary treatment modality for teeth with draining sinuses. However, it may be necessary to prescribe them if the patient develops a fever, malaise or other symptoms indicative of a systemic infection, or if the patient is medically compromised.

What are the treatment options that should be discussed with the patient?

• Non-surgical root canal re-treatment (secondary root canal treatment).
• Surgical root canal treatment (using endodontic microsurgical techniques).
• Leave alone.
• Extraction.

What treatment was decided on in this case?

Non-surgical endodontic re-treatment is generally the first line of treatment in cases where primary treatment has failed and the patient is eager to maintain their tooth. This is because the main cause of endodontic treatment failure is the persistence of microorganisms within the root canal system following primary therapy. To eradicate the remaining microbes, non-surgical endodontic re-treatment, carried out by an experienced and skilled clinician using a strict aseptic technique, offers the best chance of success.

In keeping with this rationale, non-surgical endodontic re-treatment was carried out in this case in the first instance. The tooth was subsequently reviewed and found not responding to this conventional therapy. As a result, endodontic apical microsurgery was indicated and carried out.

Was a periapical lesion of the size in this case ever likely to heal with conventional root canal re-treatment?

There is no evidence to suggest that large periapical lesions (represented on radiographs by large radiolucencies) require apical surgery more frequently than smaller ones to achieve healing. It is generally accepted that a proportion of radicular cysts will not respond to conventional, non-surgical root canal treatment. However, it is not possible to differentiate between a cyst and granuloma by their radiographic characteristics, including size. As such, all teeth which exhibit periapical radiolucencies and are deemed to have undergone unsuccessful initial root canal treatment, should first be re-treated non-surgically, for the reasons outlined already.

What is endodontic microsurgery?

Endodontic microsurgery involves the use of the dental operating microscope and micro-instruments, such as micro-mirrors and very small ultrasonic tips, to carry out endodontic surgery under high magnification.

What are the advantages of endodontic microsurgery?

In contrast to conventional endodontic surgical techniques which employed standard sized surgical instruments without magnification, the microsurgical approach allows endodontic surgery to be performed with smaller osteotomies. It enables the clinician to resect the root end with shallower bevels, and prepare the root end and any isthmuses in line with the canal. In addition, it allows visual inspection of the resected root surface so that the retrograde filling can be accurately placed (Table 5.6.1).

Table 5.6.1 Advantages of microsurgical over conventional surgical techniques

What are the indications for endodontic microsurgery?

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