What Happens During a Root Canal Treatment in London? A Step-by-Step Guide

Being told you need a root canal can feel daunting — particularly when you are not entirely sure what the procedure involves. Many patients find that the uncertainty is more unsettling than the treatment itself. In practice, root canal treatment in London follows a structured, well-established clinical process that is designed to remove infection, preserve your natural tooth, and restore comfort.

Modern endodontic treatment has advanced considerably, and the experience is typically far more straightforward than most people expect. This guide walks you through each stage of the root canal appointment process — from the initial assessment to aftercare — so you know exactly what to expect before, during, and after your visit.

Treatment steps and recommendations are confirmed following a personalised clinical assessment.

Step 1 — Assessment and Digital Imaging

Every root canal treatment begins with a thorough assessment. Your dentist will take a detailed history of your symptoms — when the pain started, what makes it better or worse, and whether you have noticed any swelling or sensitivity.

• Clinical examination — your dentist will examine the tooth and surrounding tissues, checking for swelling, tenderness, and any visible signs of decay or damage
• X-rays or digital imaging — periapical radiographs provide a detailed view of the tooth roots, surrounding bone, and any signs of infection at the root tips. These images are essential for planning the procedure
• Vitality testing — cold testing or electric pulp testing may be used to assess whether the nerve inside the tooth is still alive or has already died
• Treatment planning — based on the findings, your dentist will explain the diagnosis, outline the recommended treatment approach, and discuss how many appointments may be needed

This initial assessment is a critical step. It allows your dentist to determine the extent of infection, identify the number and shape of the root canals, and plan the treatment with precision. No two teeth are identical, so the assessment ensures your treatment plan is tailored to your specific situation.

Step 2 — Local Anaesthetic and Comfort Preparation

Before any treatment begins, the area around the affected tooth is numbed using local anaesthetic. This is the same type of anaesthesia used for routine fillings, and most patients find this the most straightforward part of the appointment.

• Numbing the tooth — your dentist will administer local anaesthetic to ensure the tooth and surrounding tissues are fully numb before any work begins. Additional anaesthetic can be given during the procedure if needed
• Comfort monitoring — throughout the treatment, your dentist will check in with you to ensure you remain comfortable. If you experience any discomfort, the procedure can be paused to allow for further anaesthesia
• Rubber dam placement — a thin latex or non-latex sheet (called a rubber dam) is placed around the tooth. This isolates the treatment area, keeps it dry, and prevents any debris or irrigation solutions from entering your mouth

Step 3 — Accessing the Infected Pulp

Once the tooth is numb and isolated, your dentist will create a small access opening in the top of the tooth. This is what happens during a root canal at its most fundamental level — gaining controlled access to the internal canal system where the infection resides.

• Small opening — using a precision drill, your dentist creates a carefully placed opening through the crown of the tooth to reach the pulp chamber beneath
• Removing infected tissue — the infected or inflamed pulp tissue is carefully removed from the chamber and the upper portions of the canals. This is the step that eliminates the source of pain and infection
• Cleaning infected tooth pulp — all diseased soft tissue, bacteria, and debris are removed from the pulp chamber. This creates a clean workspace for the next stages of treatment

This step is typically performed under magnification to ensure precision. The goal is to remove all infected material while preserving as much healthy tooth structure as possible, which contributes to the long-term strength and viability of the tooth.

Step 4 — Cleaning and Shaping the Canals

This is often the most time-intensive part of the root canal procedure steps, and it is also one of the most important. The root canals — the narrow channels that run from the pulp chamber down through each root — must be thoroughly cleaned, shaped, and disinfected.

• Specialised instruments — thin, flexible files are used to carefully clean and shape each canal. These instruments are designed to navigate the natural curves of the root without damaging the surrounding tooth structure
• Irrigation — antimicrobial solutions are used to flush the canals throughout the cleaning process. This helps dissolve remaining tissue, remove bacteria, and disinfect areas that instruments alone cannot reach
• Measuring canal length — electronic apex locators and X-rays are used to determine the precise length of each canal, ensuring the cleaning extends to the tip of the root without going beyond it
• Removing bacteria — the combination of mechanical cleaning and chemical irrigation aims to eliminate as much bacteria as possible from the canal system, reducing the risk of reinfection

Modern root canal treatment benefits from advances in instrument design, irrigation techniques, and magnification. Nickel-titanium rotary files, for example, allow for more efficient and predictable canal preparation compared with older manual methods. These endodontic treatment steps are continuously refined as evidence-based techniques evolve — though no technology can guarantee a specific outcome in every case.

Step 5 — Filling and Sealing the Tooth

Once the canals have been cleaned and shaped to the dentist’s satisfaction, they are dried and filled with a biocompatible material — most commonly gutta-percha, a rubber-like substance that conforms to the shape of the prepared canals.

• Biocompatible filling material — gutta-percha is placed into each canal along with a sealing cement. The material is designed to fill the space completely and create a tight seal that prevents bacteria from re-entering
• Sealing the root canals — the seal at the tip of each root is particularly important. A well-sealed canal prevents bacteria from the surrounding bone from migrating back into the tooth
• Preventing reinfection — the combination of thorough cleaning and effective sealing is what gives root canal treatment its long-term success. The sealed canals remove the environment in which bacteria previously thrived
• Temporary vs permanent filling — depending on the situation, your dentist may place a temporary filling over the access opening and schedule a follow-up appointment for the permanent restoration, or may complete the filling at the same visit

The quality of the seal is one of the most significant factors in long-term treatment success. Your dentist will take care to ensure the filling material extends to the correct length and that no gaps remain that could harbour bacteria.

Step 6 — Do You Need a Crown Afterwards?

In many cases, a tooth that has undergone root canal treatment will benefit from a dental crown to restore its full strength and function. This is particularly true for back teeth (premolars and molars) that bear significant chewing forces.

• Structural reinforcement — root canal treatment involves removing the pulp and creating an access opening, both of which reduce the remaining tooth structure. A crown encases the tooth, distributing biting forces evenly and reducing the risk of fracture
• Posterior teeth — back teeth are subject to much greater chewing pressure than front teeth. A crown is typically recommended for premolars and molars to protect against cracking or splitting
• Front teeth — in some cases, front teeth with sufficient remaining structure may be restored with a filling rather than a crown. Your dentist will advise based on the specific clinical situation
• Timing — the crown is usually placed within a few weeks of completing the root canal. Delaying the final restoration unnecessarily can increase the risk of the tooth fracturing or the temporary filling failing

The importance of full restoration cannot be overstated. A root canal saves the tooth from infection, but without proper protection, the remaining structure can be vulnerable. Your dentist will discuss whether a crown, onlay, or composite restoration is most appropriate for your tooth.

Can Root Canal Treatment in London Be Done in One Visit?

Many straightforward root canal treatments can be completed in a single appointment, particularly on front teeth or premolars with uncomplicated canal anatomy. However, there is no guaranteed same-day completion — the number of visits depends on several clinical factors.

• Single-visit cases — teeth with straightforward anatomy, no active infection, and good access can often be treated from start to finish in one appointment of 60–90 minutes
• Multiple-appointment cases — teeth with complex anatomy (multiple canals, curved roots), active infection, or significant inflammation may require two or more visits. Between appointments, a medicated dressing may be placed inside the canals to help control infection
• Infection severity — if there is significant active infection with swelling, your dentist may choose to clean the canals and place medication at the first visit, then complete the filling and sealing at a second appointment once the infection has settled
• Retreatment scenarios — if a previous root canal treatment has failed, retreatment is often more complex and may require additional appointments

Your dentist will discuss the expected number of appointments during your initial assessment. If urgent treatment is needed, our emergency root canal service can provide prompt access to care.

What Does It Feel Like Afterwards?

After your root canal treatment, it is normal to experience some mild tenderness or sensitivity in the treated area. This is a natural part of the healing process and typically settles within a few days.

• Mild tenderness — some discomfort around the treated tooth is common for 2–5 days following the procedure. This is usually manageable with over-the-counter pain relief such as ibuprofen or paracetamol, taken as directed
• Normal healing — the tissues around the root tip need time to settle after treatment. Any pre-existing inflammation will gradually resolve as the area heals
• Chewing precautions — avoid chewing on the treated side until any temporary filling has been replaced with a permanent restoration. Biting on a weakened tooth before a crown is placed risks fracture
• Numbness — local anaesthetic effects typically wear off within 2–4 hours. Avoid eating or drinking hot liquids until full sensation has returned to prevent accidental injury

When Should You Seek Urgent Care Instead?

In some situations, symptoms may indicate that urgent assessment is needed rather than a routine appointment. Understanding when to seek immediate care can help prevent complications.

• Significant swelling — facial swelling that is worsening, spreading, or affecting your ability to open your mouth or swallow requires urgent assessment
• Severe pain — intense, uncontrolled pain that does not respond to over-the-counter medication should be evaluated promptly
• Fever — a raised temperature in combination with dental symptoms can indicate a spreading infection that may need urgent management
• Spreading infection — signs that infection may be spreading beyond the tooth — including difficulty swallowing, swelling extending to the eye or neck, or general unwellness — require immediate attention

If you are experiencing any of these symptoms, our emergency dentist service provides prompt assessment and treatment. Early intervention in urgent situations leads to better outcomes and reduces the risk of complications.