Step-by-Step: What Happens During Root Canal Treatment?

“What happens during a root canal?” is one of the most frequently searched dental questions in the UK. For many patients, the uncertainty surrounding the root canal procedure is more anxiety-inducing than the treatment itself. Not knowing what to expect can make a straightforward appointment feel daunting.

The reality is that modern endodontic techniques are structured, precise, and designed with patient comfort as a priority. Root canal treatment follows a clear sequence of steps, each serving a specific clinical purpose. Understanding these steps beforehand can significantly reduce apprehension.

This 2026 guide walks through each stage of the root canal procedure in detail, explaining what happens, why it happens, and what you can expect at every point. Whether you have been advised that you may need treatment or are simply researching in advance, this article aims to provide the clarity and reassurance that comes from understanding the process.

Why Root Canal Treatment Is Needed

Inside every tooth lies a soft tissue called the pulp, which contains nerves, blood vessels, and connective tissue. The pulp plays an essential role during tooth development but can become a problem if bacteria reach it through deep decay, cracks, or trauma.

When infection reaches the tooth pulp, inflammation develops and can cause significant pain. Without intervention, the infection may spread to the surrounding bone and tissues. Root Canal Treatment addresses this by removing the infected tissue and cleaning the internal canal system, preventing further spread while preserving the natural tooth.

The root canal procedure is specifically designed to eliminate pulp infection while keeping the tooth’s outer structure intact. This approach avoids extraction and allows the tooth to continue functioning within the dental arch.

Step 1: Examination and Diagnosis

Before any treatment begins, a thorough clinical assessment is carried out to confirm whether root canal treatment is appropriate. This diagnostic stage ensures the correct treatment plan is developed for your individual situation.

• •Clinical examination — The dentist visually examines the tooth and surrounding area, checking for signs of infection, swelling, or structural damage
• •Sensitivity testing — Tests may be performed to assess how the tooth responds to temperature or pressure, helping to determine the condition of the pulp
• •X-rays or digital imaging — Radiographic images reveal the shape and number of root canals, the extent of any infection, and the condition of the surrounding bone
• •Confirming pulp involvement — The findings from examination and imaging are used to confirm whether the pulp is irreversibly damaged or infected, guiding the decision to proceed with endodontic treatment

This assessment forms the foundation of your treatment plan. Your dentist will explain the findings and discuss the recommended approach before proceeding.

Step 2: Local Anaesthetic

Root canal treatment is performed under local anaesthetic to numb the tooth and surrounding area. This is administered before any treatment begins, ensuring the area is fully anaesthetised before the dentist proceeds.

• •Numbing the area — Local anaesthetic is injected near the tooth to block nerve signals. The dentist will wait for this to take full effect before starting
• •Sensation vs pressure — While the anaesthetic eliminates sharp sensation, you may still feel some pressure or movement during the procedure. This is normal and does not indicate discomfort
• •Comfort check — Your dentist will confirm that the area is adequately numb before beginning treatment. If you experience any sensitivity during the procedure, additional anaesthetic can be administered

The goal is to ensure you are comfortable throughout the entire procedure. Communication with your dental team during treatment is always encouraged.

Step 3: Isolation and Access Opening

Once the tooth is numb, the next stage involves isolating it and creating a pathway to the internal canal system. This step prioritises precision and infection control.

• •Rubber dam isolation — A thin sheet of rubber (the dental dam) is placed around the tooth to isolate it from the rest of the mouth. This keeps the treatment area dry and prevents saliva or bacteria from entering the tooth during the procedure
• •Access opening — The dentist creates a small opening in the top of the tooth (the crown) to access the pulp chamber beneath. This is done with precision instruments to preserve as much healthy tooth structure as possible
• •Locating the canals — Through the access opening, the dentist identifies the individual root canals. The number and configuration vary between teeth — front teeth typically have one canal, while molars may have three or four

This careful preparation ensures the subsequent cleaning and shaping steps can be carried out effectively and safely.

Step 4: Cleaning and Shaping the Canals

The cleaning and shaping phase is the core of the root canal procedure. This is where the infected tissue is removed and the canals are prepared for sealing.

• •Removal of infected pulp — Using fine, flexible instruments, the dentist carefully removes the infected or necrotic pulp tissue from each canal. This eliminates the source of infection
• •Mechanical shaping — The canals are shaped using rotary instruments that gradually widen and smooth the canal walls. This creates a consistent shape that allows for thorough cleaning and effective sealing
• •Irrigation and disinfection — Antimicrobial irrigating solutions are flushed through the canals throughout the procedure. This removes debris, dissolves remaining tissue, and reduces bacterial load within the canal system
• •Length measurement — Electronic apex locators and radiographic images are used to determine the precise length of each canal, ensuring cleaning extends to the full depth without exceeding the root tip

Modern endodontic instruments and techniques have made this stage more efficient and precise than ever. The thoroughness of cleaning and shaping is a key factor in the long-term success of the treatment.

Step 5: Sealing the Tooth

Once the canals have been thoroughly cleaned and shaped, they are sealed to prevent bacteria from re-entering the tooth. This step is critical for the long-term success of the treatment.

• •Gutta-percha filling — The prepared canals are filled with a biocompatible material called gutta-percha, a rubber-like substance that conforms to the shape of the canal. It is placed with a sealer cement to create a tight seal
• •Sealing against bacteria — The combination of gutta-percha and sealer effectively blocks the canal system, preventing bacteria from recolonising the treated space
• •Temporary or permanent filling — The access opening is closed with a filling material. In some cases, a temporary filling is placed initially and replaced with a permanent restoration at a subsequent appointment

With the canals sealed and the access closed, the tooth is protected from further infection. The final restoration stage follows to ensure the tooth can withstand normal function.

Step 6: Final Restoration (Often a Crown)

The final stage of the root canal procedure involves restoring the tooth to its full strength and function. This step is essential because root canal treated teeth can become more brittle over time without adequate protection.

• •Structural reinforcement — A tooth that has undergone root canal treatment has had internal tissue removed and an access opening created, which can weaken its overall structure. A restoration addresses this
• •Why molars often need crowns — Back teeth bear significant biting forces during chewing. Dental Crowns encase the entire visible portion of the tooth, distributing forces evenly and protecting against fracture
• •Front teeth considerations — Front teeth may sometimes be adequately restored with a composite filling rather than a crown, depending on the amount of remaining tooth structure

Your dentist will recommend the most appropriate restoration based on the location of the tooth, the extent of structural loss, and your individual needs. This final step completes the treatment and allows you to use the tooth normally.

How Long Does Root Canal Take?

One of the most common questions patients ask is how long does root canal take. The answer depends on several factors, and understanding these can help you plan your appointment.

• •Typical duration — Straightforward root canal treatment on a front tooth or premolar typically takes around 60 to 90 minutes. This includes anaesthetic administration, rubber dam placement, cleaning, shaping, and sealing
• •Molars may take longer — Molar teeth have multiple roots and canals, often three or four, which require more time to clean and shape individually. These appointments may extend beyond 90 minutes
• •Single vs multiple visits — Some cases are completed in a single appointment, while others may be spread across two visits. The decision depends on the complexity of the anatomy and the severity of infection
• •Infection severity — Teeth with significant infection may benefit from a staged approach, where antimicrobial medication is placed inside the tooth between visits to help resolve the infection before final sealing

Your dentist will provide a more specific time estimate based on your individual case following the initial assessment.

Is Root Canal Treatment Painful?

Concerns about discomfort are among the most common reasons patients feel anxious about root canal treatment. Modern techniques and effective anaesthesia have changed the experience considerably.

• •Anaesthetic effectiveness — Local anaesthetic numbs the treatment area before any work begins. The tooth and surrounding tissues should not feel sharp sensation during the procedure
• •Pressure vs pain — You may feel pressure, vibration, or movement during treatment, but these sensations are distinct from pain. If you do experience discomfort, additional anaesthetic can be provided
• •Post-treatment tenderness — Some mild tenderness or aching around the treated tooth is common for a few days following the procedure. This is typically manageable with standard over-the-counter pain relief and usually resolves on its own

Many patients report that the root canal procedure itself was more comfortable than they expected, and often less uncomfortable than the toothache that led them to seek treatment.

Recovery After the Procedure

Understanding what to expect after root canal treatment helps you plan your recovery and recognise what is normal during the healing process.

• •Mild soreness — Some tenderness around the treated tooth and surrounding area is common for several days. This typically diminishes gradually and can be managed with over-the-counter pain relief
• •Bite sensitivity — The treated tooth may feel slightly sensitive when biting for a period following treatment. This usually improves as the area heals
• •Avoid chewing on the treated tooth — Until the permanent restoration is placed, it is advisable to avoid chewing hard foods on the treated side to protect the tooth from fracture
• •Follow-up appointments — Your dentist will schedule follow-up visits to check healing and place the final restoration. Attending these appointments is important for the long-term success of the treatment

In cases where a tooth cannot be saved and extraction is necessary, replacement options such as Dental Implants may be discussed. However, root canal treatment aims to avoid extraction by preserving the natural tooth wherever clinically appropriate.

When to Contact Your Dentist After Treatment

While some post-treatment symptoms are expected, certain signs warrant contacting your dental practice for evaluation. Knowing what to look out for helps you respond appropriately.

• •Persistent pain — If discomfort continues beyond a few days without improvement, or if it intensifies rather than gradually resolving, contact your dentist for assessment
• •Swelling — Any visible swelling in the face, gums, or jaw area following treatment should be reported to your dental practice promptly
• •Bite discomfort — If you notice that your bite feels uneven or the treated tooth sits higher than expected when closing your mouth, the restoration may need minor adjustment
• •Concerns about the crown or filling — If a temporary filling loosens or dislodges, or if there are any issues with a crown, arranging a review appointment promptly helps protect the treated tooth

These points are provided as general guidance. Your dentist will give you specific post-treatment instructions and contact information at the time of your appointment.

Booking Root Canal Treatment in London

If you have been advised that root canal treatment may be needed, or if you are experiencing symptoms that concern you, a structured consultation is the appropriate first step.

• •Structured consultation — A thorough examination with appropriate imaging provides the clinical information needed to develop an accurate diagnosis and treatment plan
• •Transparent discussion — Your dentist will explain the findings, outline the treatment steps, discuss the expected timeline and provide clear information about fees before any treatment proceeds
• •Personalised treatment planning — Every tooth and every patient is different. Your treatment plan will be tailored to your specific clinical needs, preferences, and circumstances

Understanding the root canal treatment steps beforehand allows you to approach your appointment with confidence, knowing what to expect at each stage of the process.

Treatment suitability and diagnosis can only be determined following a clinical assessment.

People Also Ask

What happens in a root canal procedure?

During a root canal procedure, the dentist numbs the affected tooth with local anaesthetic, isolates it with a rubber dam, and creates a small access opening. The infected pulp tissue is then removed from the root canals, which are cleaned, shaped, and disinfected using specialised instruments and antimicrobial solutions. The prepared canals are filled with gutta-percha and sealed. The tooth is then restored, typically with a filling or crown, to protect its structure and function.

How long does root canal take?

Root canal treatment typically takes around 60 to 90 minutes for straightforward cases involving front teeth or premolars. Molars with multiple canals and more complex root anatomy may require longer appointments or be completed across two separate visits. The duration depends on factors including the tooth involved, the extent of infection, and the complexity of the canal anatomy. Your dentist will provide a time estimate based on your individual case.

Is root canal done in one visit?

Some root canal cases can be completed in a single appointment, particularly when the infection is localised and the root anatomy is straightforward. Other cases may require staged treatment over two visits, allowing time for antimicrobial medication to work within the tooth between appointments. The decision depends on the severity of infection, complexity of the root canals, and the clinical judgement of the treating dentist.

Do they remove the whole tooth during root canal?

No, the natural tooth is preserved during root canal treatment. Only the infected or damaged pulp tissue inside the tooth is removed — the outer structure, including the enamel and root, remains intact. A small access opening is made in the crown of the tooth to reach the pulp chamber, but this is subsequently restored with a filling or crown. The goal of the endodontic procedure is specifically to save the tooth and avoid extraction.

Will I need a crown after root canal?

A crown is often recommended after root canal treatment, particularly for back teeth such as molars and premolars that bear significant biting forces during chewing. The crown encases the visible portion of the tooth, providing structural reinforcement and protecting against fracture. Front teeth may sometimes be adequately restored with a composite filling depending on the amount of remaining tooth structure. Your dentist will advise on the most appropriate restoration for your specific case.