Root Canal Treatment (RCT) - Overview

What Is It?

Anatomy - The Tooth Structure

• Enamel - the hard outer covering of the visible crown
• Dentin - denser than bone, forms the majority of tooth substance, very sensitive to pain
• Pulp - the innermost core of myxomatous (jelly-like) tissue containing blood vessels and nerve supply

Why Is It Needed?

1. Reversible pulpitis: Infection is limited to outer pulp. Tooth is sensitive to hot/cold and percussion, but pain resolves when the irritant is removed. May not yet require RCT.
2. Irreversible pulpitis: Infection spreads throughout the pulp. Pain is severe, sharp or throbbing, may worsen when lying down. RCT is now necessary.
3. Pulp necrosis: The pulp dies. Pain may be constant or intermittent; cold sensitivity is lost. RCT is required.

• Periapical granuloma or cyst (seen as radiolucency at the root apex on X-ray)
• Osteomyelitis of the alveolar bone
• Parulis ("gum boil") if the abscess drains through the gingiva
• Ludwig's angina - serious spreading cellulitis of the submandibular space and floor of the mouth

Indications

• Irreversible pulpitis (bacterial invasion of the pulp that cannot heal on its own)
• Pulp necrosis with or without periapical abscess
• Crown-root fractures involving the pulp
• Deep dental caries reaching the pulp chamber
• Significant dental trauma (Ellis Class III fractures, which cause pulp necrosis in 10-30% of cases)
• Symptomatic periapical periodontitis

The Procedure - Step by Step

1. Diagnosis and X-ray: The dentist or endodontist examines the tooth and takes a periapical X-ray to assess the extent of infection and the root canal anatomy.
2. Local anaesthesia: The area is numbed. (Contrary to popular belief, modern RCT is typically no more painful than a routine filling.)
3. Dental dam placement: A rubber sheet isolates the tooth to maintain a clean, dry field and prevent recontamination from saliva.
4. Access opening: A small hole is drilled through the crown to access the pulp chamber.
5. Pulp removal and canal shaping: Using small files (hand or rotary instruments), the dentist removes all pulp tissue and shapes the canals to allow proper filling. Irrigation with disinfectants (e.g., sodium hypochlorite) cleans the canals.
6. Drying the canals: The canals are dried with paper points.
7. Obturation (filling): The canals are filled with gutta-percha - a rubber-like, biocompatible material - secured with an adhesive cement. This seals the space to prevent re-infection.
8. Temporary or permanent seal: A temporary filling is placed; the definitive restoration follows at a subsequent visit.
9. Crown placement: Because the tooth loses blood supply and can become brittle, a crown (cap) is placed over it to restore full function and prevent fracture.

After the Procedure

• Some post-procedure soreness for a few days is normal and managed with over-the-counter pain relief.
• The restored tooth can function like any natural tooth for many years or even a lifetime with good oral hygiene.
• If the infection was severe, the tooth may be left open to drain for 1 or more days before final sealing.
• In some cases (e.g., if there is insufficient tooth structure), a post is placed inside the canal before the crown is fitted.

Alternatives

Key Points