Endodontic treatment, commonly called a root canal, is a dental procedure used to repair and save a tooth that is badly damaged or infected. What exactly does endodontic treatment involve, and how is it performed? Endodontic treatment seeks to eliminate infection and inflammation from the inner layers of the tooth, known as the pulp and root canal system.

The anatomy of teeth, including pulp, dentin, enamel, and cementum

Understanding Tooth Anatomy and Function

To understand endodontic treatment, it’s helpful to first review tooth anatomy and function. Each tooth contains an inner soft living portion called the pulp, located within a hard protective shell of dentin. The pulp contains blood vessels, connective tissue, and nerves that enter the tooth through a small opening at the tip of the root.

The hard outer layers of the tooth include enamel covering the crown and cementum coating the root. The periodontal ligament surrounds and holds the tooth in place. The root extends below the gums into the alveolar bone of the upper or lower jaw. The pulp is responsible for forming dentin as the tooth develops and responds to stimuli like hot or cold to help us sense pain or temperature change.

Causes of Tooth Damage and Infection

Unfortunately, the pulp is vulnerable to damage and infection through cracks, decay, or trauma. Bacteria from dental decay or periodontal disease can sometimes infiltrate the pulp chamber or root canal system. Left untreated, this leads to pulpitis or pulp necrosis as the soft tissue becomes inflamed and eventually dies off. Symptoms may include sensitivity to hot/cold, spontaneous pain, swelling, or pain from biting and chewing.

Endodontic Treatment Goals and Process

Endodontic treatment, or root canal treatment, aims to remove any remaining infected or damaged pulp tissue from the interior tooth structures and seal off the root canal system. This eliminates the source of infection and allows the tooth to be retained and restored to proper functioning. The basic steps involve:

  • Anesthesia: The tooth and surrounding gum tissue are numb, and local anesthesia injections are used.
  • Access cavity: The dentist creates an opening through the chewing surface of the tooth using a small drill or bur to gain access to the pulp chamber.
  • Instrumentation: Endodontic files gently shape the root canal space and remove pulp debris. Files come in varying tapers and tips to clean all canal walls and major branches.
  • Irrigation: Antiseptic solutions like sodium hypochlorite help disinfect and flush out bacteria between file use. Care is taken not to extrude irrigants beyond the root tip.
  • Intra-canal medication: An antimicrobial medicine like calcium hydroxide may be placed inside canals as an interappointment dressing to further disinfect any remaining tissues.
  • Obturation: Once thoroughly cleaned and shaped, the canal space is tightly filled with gutta-percha, a biocompatible rubber-like material, and bonded in place using a sealer cement.
  • Restoration: The tooth access cavity is rebuilt and sealed with a filling or crown to fully encapsulate the new root canal filling and prevent reinfection.
The step-by-step process of treatment

Root Canal Procedure Details

Let’s look more closely now at some key steps in endodontic treatment:

Local Anesthesia

Local anesthetics are administered using very thin needle injections to treat the tooth pain-free properly. The most common is lidocaine with epinephrine, which provides safe and effective numbness for 45-120 minutes. Patience is needed to allow full anesthesia before beginning instrumentation.

Pulp Removal

After accessing the pulp chamber, endodontic files or small hand instruments are slowly used to carefully remove any remaining pulpal tissue from the main canal and extra canals if present. Sterile gloves, masks, and copious irrigation help maintain the aseptic technique.

Shape and Clean

Filing the canal lets the dentist shape it uniformly to a tapered cone design required for optimum filling. Larger files are used at the chamber entrance, gradually tapering to smaller tips at the anatomical apex. Twisting motions coupled with irrigation remove all organic remnants and exposed dentin shavings.


Numerous irrigants rinse away debris, but sodium hypochlorite (bleach) excels at dissolving tissues and eliminating bacteria due to its oxidative properties. Careful agitation onto canal walls along the full working length is paramount for successful decontamination.

Intracanal Medicaments

When temporarily placed, calcium hydroxide raises the pH to toxic levels for any remaining microbes. Its healing properties also help neutralize inflammation within the surrounding periodontium during multiple-visit therapy.


After thoroughly cleaning and disinfecting the root canal system, it must be sealed to prevent recontamination. Gutta-percha, a thermoplastic filling material, is condensed into the canal space along with biocompatible sealer cement. Warm vertical or cold lateral compaction techniques compact the material three-dimensionally.

Restoration and Follow-up

Covering the new filling with a final restoration protects it from mechanical disruption or microbial leakage. Follow-up x-rays check for periapical healing over subsequent months as the tooth remodels in response to the successful treatment. Retreatment may be needed if symptoms persist or recur.

Special Considerations and Challenges

Anatomic Complexities

Though most teeth have a single root canal, others, like mandibular premolars, often contain extra canals requiring complete negotiation. Advanced imaging aids in the location and three-dimensional cleaning of all root canal anatomy.

Periapical Pathology

Severe infections may cause apical periodontitis, which is visible on X-rays as radiolucencies at the tooth tip. If the source of infection is removed, these periapical lesions usually heal over 6-12 months post-treatment. Persistent lesions may signal the need for retreatment.

Separated Instruments

Occasionally, an endodontic file can separate or inadvertently be pushed beyond the root tip during cleaning. Specialized tools and techniques aim to bypass, remove, or surgically retrieve such separated instruments to prevent periapical pathology.

Cracked Teeth

Fractured but non-mobile teeth may be amenable to root canal therapy if the cracks are not through and through. Correct diagnosis helps determine if extra post-space strengtheners or a crown are also necessary after treatment.

Failed Root Canals

Occasionally, prior suboptimal treatment leads to retreatment being indicated. Advanced ultrasound, rotary nickel-titanium systems, and surgical microscopes now enhance success rates for even the most challenging retreatments.

Prognosis and Success Rates

Given the careful aseptic protocols followed, modern endodontic treatment enjoys high success rates of over 86%, which increase to up to 98% when performed on a single-visit basis by an endodontist. Multiple factors influence outcomes, but satisfaction comes from knowing every effort was made to save natural, healthy teeth with root canal treatment when possible.


In summary, endodontic treatment aims to heal and maintain teeth that would otherwise require extraction through non-surgical root canal procedures. Anatomy, infection control through meticulous cleaning and shaping techniques, intracanal medications, and high-quality obturation seals are key. Advanced technology now optimizes success even in difficult cases. While not without some risks inherent to dental surgery, root canal treatment strongly favors saving natural dentition and function where achievable.