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General Dentistry25 March 202611 min read
What Happens During a Root Canal Step by Step?
You notice a dull, persistent ache in one of your back teeth. It flares when you drink your morning coffee and lingers through your commute into the City. You try to ignore it — meetings are stacked, deadlines are looming — but the discomfort is becoming harder to dismiss. Eventually, you search online: what actually happens during a root canal?
You are far from alone. Root canal treatment is one of the most commonly searched dental procedures in the UK, yet it remains widely misunderstood. Many patients associate it with pain, when in reality the procedure is designed to relieve it. Understanding what a root canal step by step involves can help reduce anxiety and support informed decision-making before attending a consultation. For a broader overview of the procedure and why it may be recommended, our guide on how dentists save a tooth with root canal treatment in the City of London provides helpful context.
Whether you are experiencing tooth sensitivity, have been advised that endodontic treatment may be necessary, or simply want to understand the process, this guide provides a clear, clinically grounded overview. Knowing what to expect — from initial assessment through to aftercare — can make the experience feel far more manageable. As with all dental treatments, suitability depends on individual clinical assessment, and professional advice should always be sought where symptoms are present.
A root canal is an endodontic procedure designed to treat infection or inflammation within the pulp of a tooth. The dental pulp is the soft tissue inside the tooth that contains nerves, blood vessels, and connective tissue. When this pulp becomes damaged — through deep decay, cracks, trauma, or repeated dental procedures — bacteria can enter and cause infection.
Left unaddressed, pulp infection may lead to abscess formation, bone loss around the root tip, or spreading infection. Root canal treatment aims to remove the infected or inflamed tissue, clean and shape the internal canal system, and seal the tooth to prevent reinfection.
The goal is to preserve the natural tooth structure wherever clinically appropriate, avoiding extraction. The term “root canal” refers both to the natural anatomical space within the tooth root and to the treatment procedure itself. In the UK, this treatment is carried out by general dentists or specialist endodontists, depending on the complexity of the case.
What happens during a root canal step by step? A root canal involves numbing the tooth, isolating it with a rubber dam, removing infected pulp tissue, cleaning and shaping the root canals, disinfecting the internal space, and sealing it with a biocompatible filling material. A restoration, often a crown, is typically placed afterwards to protect the treated tooth. The procedure is usually completed in one or two appointments.
Several clinical situations may indicate that root canal treatment could be appropriate. It is important to note that only a thorough examination — often including dental radiographs — can confirm whether endodontic treatment is the most suitable option.
Common reasons a root canal may be considered include:
Symptoms that sometimes accompany pulp problems include prolonged sensitivity to hot or cold, spontaneous pain, tenderness when biting, swelling of the gum near the affected tooth, or darkening of the tooth. Our guide on signs you may need root canal treatment in the City of London covers these symptoms in greater depth. However, in some cases, a tooth requiring root canal treatment may be entirely asymptomatic and only identified during routine examination.
If you are experiencing any of these symptoms, seeking a professional assessment is a sensible step. For patients in the City of London, emergency dental care in the City of London may be appropriate where symptoms are acute or worsening.
The root canal process begins well before any clinical work takes place. Your dentist will carry out a comprehensive assessment, which typically includes:
Based on these findings, your dentist will explain whether root canal treatment is clinically indicated, discuss alternative options such as extraction, and outline the expected number of appointments. Treatment planning is always individualised — no two root canal cases are identical.
This stage is also an opportunity to ask questions. Understanding the procedure, expected outcomes, and any limitations is an important part of informed consent.
On the day of treatment, the first clinical step is ensuring your comfort. Local anaesthesia is administered to thoroughly numb the tooth and surrounding area. For most patients, this means the procedure itself should not be painful — though mild pressure or vibration may be felt.
Once the area is numb, a rubber dam (a thin, flexible sheet) is placed around the tooth. This serves several important functions:
While the rubber dam may feel unusual, it is a standard and essential part of safe endodontic practice. Your dentist will ensure you are comfortable before proceeding.
Using a dental drill, your dentist creates a small opening in the crown of the tooth to gain access to the pulp chamber. For back teeth (molars and premolars), this access point is typically on the biting surface. For front teeth, it is usually on the back surface.
This is a precise step. The aim is to create an opening large enough to work through while preserving as much natural tooth structure as possible.
Once the pulp chamber is accessed, the infected or necrotic pulp tissue is carefully removed using specialised instruments called endodontic files. These thin, flexible instruments are designed to navigate the narrow root canals — which can be curved, branched, or very fine — and remove all diseased tissue.
When bacteria invade the dental pulp, the body’s immune response triggers inflammation within a confined space. Unlike most tissues, the pulp has limited capacity to swell because it is enclosed within the rigid walls of the tooth. This pressure on the nerve fibres is what often causes the intense, throbbing pain associated with pulpitis.
As infection progresses, the pulp tissue may die (necrosis), and bacteria can spread beyond the root tip into the surrounding bone, forming a periapical abscess. Root canal treatment interrupts this process by physically removing the source of infection and creating conditions that allow the surrounding bone and tissues to heal.
After the pulp tissue is removed, the canals are meticulously cleaned and shaped. This involves:
This step is often the most time-consuming part of the procedure, particularly in teeth with multiple or complex canals. Thorough cleaning and shaping are essential for long-term success.
Once the canals are clean, dry, and shaped, they are filled with a biocompatible material — most commonly gutta-percha, a natural rubber-like substance. This material is placed into the canals along with a sealing cement to create a three-dimensional seal that prevents bacteria from re-entering.
The access cavity is then sealed with a temporary or permanent filling material. In many cases, a final restoration — typically a dental crown — is recommended to protect the tooth and restore its full function. Teeth that have undergone root canal treatment can become more brittle over time, and a well-fitting crown significantly reduces the risk of fracture.
Your dentist will advise on the most appropriate restorative options in the City of London based on the specific tooth and your clinical needs.
Recovery following root canal treatment varies between patients, but common experiences include:
Over-the-counter pain relief, such as paracetamol or ibuprofen (where medically appropriate), is usually sufficient to manage post-treatment discomfort. If you are wondering about getting back to the office, our guide on returning to work after dental treatment in the City of London offers practical advice. Your dentist will provide specific aftercare instructions.
It is important to avoid biting on hard foods with the treated tooth until the final restoration is in place. Attending any follow-up appointments is essential to ensure the tooth is healing appropriately.
If you are experiencing any of the following, it may be worth seeking a clinical evaluation:
These symptoms do not necessarily mean a root canal is needed — many conditions can produce similar signs. However, early assessment allows for timely diagnosis and a wider range of treatment options. For patients working in or near the City of London, general dental consultations in the City of London provide an appropriate starting point.
Avoid self-diagnosis. A thorough clinical examination is the only reliable way to determine the cause of dental symptoms.
While not all causes of pulp damage are preventable, good oral health practices can significantly reduce the risk:
Early intervention for small cavities or cracks can often prevent the need for more extensive treatment later.
With modern local anaesthesia, root canal treatment should not be painful during the procedure. Most patients report feeling pressure or vibration but not pain. Some mild tenderness around the tooth is common for a few days afterwards, typically manageable with standard over-the-counter pain relief. If you experience significant or worsening pain following treatment, contact your dental practice for advice. Anxiety about the procedure is entirely normal, and your dentist can discuss options to help you feel more comfortable, including explaining each step as it happens.
A root canal procedure typically takes between 60 and 90 minutes per appointment, depending on the tooth involved. Front teeth with a single canal are generally quicker to treat, while molars with three or four canals may require longer or even a second appointment. Complex cases — such as teeth with unusual anatomy, curved roots, or previous failed treatment — may take additional time. Your dentist will provide an estimated treatment duration during the planning stage based on your specific clinical situation.
Root canal treatment costs in London vary depending on several factors, including the tooth position, number of canals, complexity, and whether the treatment is carried out by a general dentist or an endodontist. Private fees in London typically range from several hundred pounds upwards. A final restoration such as a crown represents an additional cost. Our detailed guide to root canal costs in the City of London provides a more thorough breakdown. Your dental practice should provide a clear treatment plan with associated fees before proceeding. NHS root canal treatment is available at a lower cost, though waiting times and availability may vary.
If root canal treatment is indicated but not carried out, the infection within the tooth may progress. This can lead to abscess formation, increased pain, swelling, bone loss around the root, and potentially the spread of infection to adjacent teeth or tissues. In some cases, the tooth may eventually require extraction. However, it is important to discuss all available options — including extraction and replacement — with your dentist, as the most appropriate approach depends on your individual clinical circumstances and preferences.
While root canal treatment has a high success rate — with published clinical studies generally reporting outcomes between 85% and 97% depending on the clinical circumstances — no dental procedure can guarantee a permanent outcome. Factors that may affect long-term success include the complexity of the canal anatomy, the extent of the original infection, and how well the tooth is restored afterwards. If a previously treated tooth develops new symptoms, retreatment or alternative approaches may be considered. Regular dental reviews help monitor treated teeth over time.
The main alternative to root canal treatment is extraction of the affected tooth. Our guide on tooth extraction vs root canal in the City of London explores when each approach may be appropriate. If a tooth is removed, replacement options such as a dental implant, bridge, or denture may be considered to restore function and appearance. In some cases, where pulp inflammation is very early and reversible, other conservative approaches may be appropriate. Your dentist will discuss all suitable options during your consultation so that you can make an informed decision based on your clinical needs and personal preferences.
Understanding what happens during a root canal step by step can help ease concerns and support better-informed conversations with your dental team. The procedure is a well-established method of preserving natural teeth and relieving the pain associated with pulp infection. From diagnosis through to final restoration, each stage is designed to remove infection, protect the remaining tooth structure, and promote healing.
If you are experiencing symptoms that may indicate a pulp problem, or if you have been advised that root canal treatment may be appropriate, seeking a thorough clinical assessment is the most important first step. Treatment planning should always be individualised, taking into account your specific dental anatomy, symptoms, and overall health.
Maintaining good oral hygiene, attending regular check-ups, and addressing dental problems early remain the most effective ways to protect your long-term dental health.
Dental symptoms and treatment options should always be assessed individually during a clinical examination.
Disclaimer: This article is intended for general educational purposes only and does not constitute personalised dental advice. Individual diagnosis and treatment recommendations require a clinical examination by a qualified dental professional.