4.6: Obturation of the root canal system

What did the radiograph reveal?

  • Gutta-percha point tracked to the periradicular region around the 35 and 36.
  • A large periapical lesion associated with the 35 and 36.
  • An overhanging amalgam restoration on the distal aspect of the 35.

Why should sinus tracts be traced with a gutta-percha point?

Sinus tracts can be traced with a gutta-percha point and a radiograph taken to help confirm the source of the disease. The location of the sinus tract may be misleading as it may exit the tissues some distance from the origin of the infection. Therefore, an attempt to ‘trace’ the sinus reduces the likelihood of misdiagnosis.

Diagnosis and treatment planning

What was the diagnosis for teeth 35 and 36?

A diagnosis of chronic periapical periodontitis with suppuration associated with the infected necrotic root canal systems of the 35 and 36 was reached.

What was the likely aetiology of the infection?

Large, poorly adapted restorations on the 35 and 36 resulted in microleakage and the progression of secondary caries. The microorganisms within the carious lesion elicit inflammation in the pulp. This inflammatory process begins when the caries is some distance from the pulp and intensifies as the caries approaches the pulpal tissue. Over a period of time, the bacteria invade the root canal, overpowering the dentine–pulp complex’s natural defences, resulting in necrosis. The microorganisms and their byproducts will eventually cause periapical inflammation.

What is the difference between chronic periapical periodontitis and a chronic periapical periododntitis with suppuration?

The formation of a periapical granuloma or a periapical abcess can occur as a periapical tissue response to root canal infection. In cases of chronic periapical periodontitis, the invading bacteria are generally contained within the root canal system by the host defences. As such, the inflammatory process is initiated and sustained by bacterial toxins and by-products released from the root canal into the surrounding tissues.

In a chronic periapical periododntitis with suppuration, bacteria may be found both in the root canal and within the extraradicular tissues. Apical disease is dynamic and there is build-up of pus within the tissues; this is periodically discharged into the oral cavity via a fistulous or sinus tract.

Both chronic periapical periodontitis and chronic periapical periododntitis with suppuration can resolve after non-surgical root canal treatment, as the source of infection is from within the root canal system. After the root canal has been disinfected and sealed, the host defence will generally be able to eliminate any extraradicular bacteria present within the apical abcess. Therefore, surgical intervention is generally not required.

What were the treatment options?

  • No treatment.
  • Root canal treatment of the 35 and 36.
  • Extraction of the 35 and 36.

The patient wished to retain his teeth, and root canal treatment of both teeth was chosen.


What are the principle stages of root canal treatment?

  • Establish access for chemo-mechanical disinfection and debridement of the root canal system.
  • Shaping of the canal(s) to facilitate three-dimensional obturation of the disinfected root canal(s).
  • Obturation of the root canal(s) to produce an optimal apical, lateral and coronal seal.
  • Placement of a well-adapted coronal restoration to provide a robust coronal seal.

Endodontic treatment was carried out over multiple visits. At the first visit, the amalgam restoration was removed from the 36 and each tooth assessed. An orthodontic band was trimmed and cemented around the 36.

Why was the entire amalgam restoration removed?

It is important to assess the restorability of a tooth prior to embarking on root canal treatment. In this case, secondary caries was evident around the existing restoration and it was uncertain how much sound tooth structure remained. Therefore, the restoration had to be removed in order to assess the quality, quantity and position of coronal tooth tissue. It is also paramount to remove all caries to prevent contamination of the root canal during treatment.

What was the purpose of the orthodontic band?

After removal of the large amalgam restoration in the 36, it was important to preserve remaining tooth structure and reduce the risk of tooth fracture during or immediately after root canal treatment. Therefore, an orthodontic band was placed to protect the tooth. This extra-coronal support also facilitated placement of a secure and well-sealing rubber dam.

An access cavity was prepared and the canals were irrigated with sodium hypochlorite using a pre-measured needle. The working lengths were estimated from the diagnostic radiographs and the electronic apex locator. This was confirmed by taking a working length radiograph (Figure 4.6.2a). The tooth was mechanically instrumented using a combination of stainless steel and nickel–titanium instruments while profusely irrigating with sodium hypochlorite.

Figure 4.6.2 (a) Working length radiograph the 36 and, (b) post-obturation radiograph of the 36.

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Mar 13, 2015 | Posted by in Endodontics | Comments Off on 4.6: Obturation of the root canal system

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