What is a Root Canal? A Comprehensive Patient Guide
What is a Root Canal? A Comprehensive Patient Guide
Written by Dr Jennifer Tirtawijaya
BDS (Hons), University of Otago
General Dentist, 1 Health Dental, Christchurch
Dr Jennifer Tirtawijaya is a highly qualified general dentist at 1 Health in Christchurch. She holds a Bachelor of Dental Surgery with Honours from the University of Otago and provides high-quality root canal treatments and a full range of dental care to her patients. Dr Tirtawijaya is dedicated to delivering evidence-based and compassionate dentistry for all ages, with a focus on clear communication and patient comfort.
Understanding Root Canal Treatment
A root canal is a common dental procedure designed to save a tooth that has become infected or severely damaged inside. Despite its intimidating reputation, modern root canal therapy is a routine treatment that actually relieves pain rather than causes it. If you're experiencing tooth pain or your dentist has mentioned a root canal, this guide will walk you through everything you need to know.
What Happens Inside Your Tooth?
To understand why a root canal becomes necessary, it helps to know a bit about tooth anatomy. Beneath the hard outer layers of your tooth—the enamel and dentin—lies a chamber filled with soft tissue called the pulp. This pulp contains nerves, blood vessels, and connective tissue that help your tooth grow during development. Once your tooth is fully mature, it can survive without the pulp because the tooth continues to be nourished by the tissues surrounding it.
When decay, damage, or injury reaches the pulp, it becomes infected or inflamed. This is where a root canal becomes necessary—the infected pulp must be removed to save your tooth and relieve your pain.
Common Signs You Might Need a Root Canal
Not all toothaches require root canal treatment, but certain warning signs suggest it's time to see your dentist promptly.
Persistent Tooth Pain: Throbbing or sharp pain, especially when chewing or biting down, can indicate pulp inflammation. This pain may be constant or intermittent, ranging from dull to severe.
Lingering Sensitivity: If hot or cold foods and beverages cause discomfort that lingers long after you've finished eating or drinking, it may signal pulp problems. This differs from typical tooth sensitivity, which usually fades quickly.
Swollen or Tender Gums: Inflammation and tenderness around a specific tooth, particularly if accompanied by a small pimple-like bump on the gums, may indicate a dental abscess—a collection of pus caused by tooth infection.
Tooth Discolouration: A tooth that turns dark yellow, grey, or brown may indicate a compromised blood supply, often due to pulp damage or infection. Discolouration suggests the nerve inside is dying or dead.
Visible Damage: Cracks, chips, or deep decay that's visible or can be felt with your tongue warrant prompt dental attention, as these expose the inner tooth to bacteria.
If you experience any of these symptoms, don't delay—book an appointment with your dentist as soon as possible. Early treatment prevents complications and often leads to better outcomes.

What Causes the Need for Root Canal Treatment?
Several factors can compromise your tooth's pulp, making root canal therapy necessary.
Deep Decay: This is the most common cause. When cavities penetrate through the enamel and dentin to reach the pulp chamber, bacteria invade and cause infection. The longer decay goes untreated, the deeper it travels.
Tooth Trauma: Accidents, sports injuries, falls, or any blow to the mouth can damage the tooth, even if there's no visible crack. Trauma may kill the nerve inside, leading to pulp necrosis and eventually requiring root canal treatment.
Repeated Dental Procedures: Each time a tooth undergoes filling, crown placement, or other dental work, its structure weakens. Over time, this accumulated stress can lead to pulp exposure and infection.
Cracked or Chipped Teeth: Fractures create pathways for bacteria to reach the pulp. Even small cracks can allow infection to develop over time.
Untreated Gum Disease: Severe periodontal disease can cause the gum line to recede, exposing the tooth root. Without treatment, bacteria can travel down the root surface and compromise the pulp.
The Root Canal Procedure: What to Expect
Modern root canal treatment typically takes one to three appointments, depending on the tooth's complexity and infection severity. Here's what happens at each stage.
Step 1: Diagnosis and Planning
Your dentist will examine the affected tooth and take X-rays or advanced imaging (like CBCT scans) to assess the extent of infection and visualise the root canal anatomy. This helps your dentist create a precise treatment plan tailored to your specific situation.
Step 2: Anaesthesia
Before beginning, your dentist applies local anaesthesia to numb the tooth and surrounding area. You'll feel pressure and vibration during the procedure, but you should not experience pain. If you do feel discomfort, let your dentist know immediately—they can administer additional anaesthetic.
Step 3: Pulp Removal and Canal Cleaning
A small opening is carefully made through the crown of the tooth to access the pulp chamber. Using specialised instruments, your dentist removes the infected or inflamed pulp tissue. This eliminates the source of pain and stops the infection from spreading.
The root canals are then thoroughly cleaned, shaped, and disinfected. Modern techniques often use ultrasonic irrigation and antimicrobial solutions like sodium hypochlorite to ensure bacteria are eliminated from even the smallest branches of the canal system.
Step 4: Filling and Sealing
Once the canals are cleaned and shaped, they're filled with a biocompatible material called gutta-percha—a rubber-like substance that seals the canals and prevents bacteria from re-entering. A sealer cement ensures the material bonds securely within the canal space.
Step 5: Restoration
A temporary filling may be placed to protect the tooth while it heals. At a follow-up appointment, your dentist typically places a permanent crown over the treated tooth. Because root canal-treated teeth become more brittle over time without their nerve supply, a crown provides essential protection and restores full function, allowing you to chew normally.

Debunking Common Root Canal Myths
Myth: Root canals are extremely painful. This misconception likely stems from outdated procedures performed before modern anaesthetics were widely available. Today, root canal treatment is no more uncomfortable than having a filling placed. Local anaesthesia ensures you remain numb throughout the procedure. Some mild discomfort in the first few days after treatment is normal and easily managed with over-the-counter pain relief.
Myth: It's better to just extract the tooth. While extraction might seem simpler, it comes with significant drawbacks. Removing a tooth puts extra stress on neighbouring teeth, causing them to shift position over time. This can lead to bite problems, jaw pain, and difficulty eating. Additionally, you'll need to consider tooth replacement options like implants or bridges, which are often more expensive and complicated than saving the tooth with a root canal.
Myth: Root canals make you sick. This claim was debunked nearly a century ago and has no scientific support. In fact, root canal treatment improves your health by eliminating infection and allowing you to maintain your natural tooth, which is always preferable to extraction.
Myth: A crown causes you to need a root canal. Crowns don't cause root canals—rather, teeth that already have extensive decay are more likely to need both treatments. The crown protects the tooth from further decay; the underlying tooth damage is what necessitates the root canal.
Success Rates and Long-Term Outcomes
Modern root canal therapy boasts impressive success rates. Studies indicate that root canals have a success rate of 86-98%, with most outcomes falling in the 90-95% range. This means the vast majority of treated teeth remain functional and pain-free for years or even a lifetime.
Several factors influence success:
Quality of the Initial Treatment: Modern techniques, proper instrumentation, and thorough disinfection of the canals all improve outcomes. Treatment performed by experienced dentists or endodontists (root canal specialists) tends to have higher success rates.
Condition of the Tooth: Teeth with severe infection or extensive damage before treatment may have a slightly lower success rate, but treatment is still worth attempting to preserve the tooth.
Compliance: Following your dentist's aftercare instructions—maintaining good oral hygiene, keeping follow-up appointments, and avoiding chewing on the treated tooth until it's fully restored—significantly improves outcomes.
Prompt Restoration: Placing a crown on the treated tooth within a reasonable timeframe protects it and improves long-term success. A tooth left without final restoration is more vulnerable to re-infection.
Recovery and Aftercare
What to Expect Immediately After Treatment
Mild discomfort is completely normal for the first 24-48 hours following root canal treatment. This typically includes:
• Mild to moderate tenderness around the tooth
• Slight sensitivity when chewing
• A dull ache in the jaw from keeping your mouth open during treatment
Recovery Timeline
Days 1-2: You may experience mild to moderate tenderness and sensitivity. Avoid chewing on the treated side of your mouth.
Days 3-4: Discomfort usually decreases noticeably as inflammation subsides.
Days 5-7: Most patients experience minimal to no discomfort. You can gradually return to normal activities and regular diet.
Pain Management Strategies
Over-the-Counter Pain Relief: Ibuprofen or paracetamol can effectively manage post-treatment discomfort. Follow dosage instructions carefully, and consult your dentist or GP if you have medical conditions or take other medications that might interact.
Cold Compress Application: Apply a cold pack or wrapped ice to the outside of your cheek near the treated tooth for 20 minutes on, followed by 20 minutes off. Cold therapy reduces swelling and eases pain, particularly within the first 24 hours.
Rest and Elevation: Keep your head elevated, especially when lying down. Limiting physical activity for 24-48 hours after treatment promotes faster healing and reduces swelling. Avoid bending or lifting, which can increase blood pressure in the jaw.
Dietary Modifications: Stick to soft foods like mashed potatoes, yoghurt, scrambled eggs, soup, and smoothies. Avoid hard, crunchy, or sticky foods that place pressure on the treated tooth. Hot foods and beverages may increase sensitivity.

When to Contact Your Dentist
While mild discomfort is expected, certain symptoms warrant prompt professional attention:
• Severe pain that doesn't respond to over-the-counter medication
• Swelling that persists or worsens after 3 days
• Throbbing discomfort that intensifies rather than improves
• Fever or signs of systemic infection
• Difficulty swallowing or breathing (rare, but seek immediate care)
These symptoms may indicate complications like persistent infection, improper sealing, or new bacterial invasion. Contact your dentist immediately if you experience any of these signs.
What Happens If You Don't Get a Root Canal?
Delaying necessary root canal treatment can lead to serious complications, both local and systemic.
Escalating Pain: What begins as occasional discomfort typically becomes constant, severe pain over time. As the infection spreads deeper, it affects increasingly sensitive nerve tissue.
Abscess Formation: An untreated infected tooth can develop a dental abscess—a pocket of pus that causes swelling in the gums, face, and potentially the neck and jaw. Abscesses are painful and require professional treatment.
Bone Loss: The infection can spread to the bone supporting your tooth, causing deterioration that weakens the tooth's foundation and can affect neighbouring teeth.
Tooth Loss: Without treatment, the tooth structure becomes progressively weaker. Eventually, the tooth either falls out on its own or requires extraction. Losing a tooth impacts your ability to chew properly, affects your appearance and confidence, and creates spaces that allow other teeth to shift.
Systemic Infection: In rare but serious cases, the infection can enter the bloodstream and spread throughout your body. Approximately 7,000 people in the United States are hospitalised annually due to complications from endodontic (pulp) infections. In extreme cases, untreated infections can become life-threatening.
More Complex and Expensive Treatment: By the time extraction becomes necessary, your only options are costly tooth replacement procedures like implants or bridges. Additionally, you may have bone loss that complicates implant placement.
The bottom line: treating the problem early with a root canal is far simpler, less expensive, and safer than dealing with the consequences of delay.
Long-Term Care for Root Canal-Treated Teeth
Once your tooth has been treated and restored with a crown, proper care helps ensure it remains healthy for years or decades.
Maintain Oral Hygiene: Brush twice daily with fluoride toothpaste and floss daily. Root canal-treated teeth can still develop decay around the margins where the crown meets the natural tooth, so meticulous oral hygiene is essential.
Regular Dental Visits: Attend your scheduled dental check-ups (typically every 6 months). Your dentist can monitor the treated tooth and spot any early signs of problems.
Avoid Damaging Habits: Don't chew on hard objects like ice, hard sweets, or pen caps. Avoid using your teeth to open packages. These habits can crack the crown or the underlying tooth.
Protect Your Teeth During Sports: Wear a mouthguard if you participate in contact sports. Trauma to a treated tooth can cause complications.
Manage Gum Disease: Treat gum disease promptly. Infection spreading from the gums can compromise a previously successful root canal treatment.
Watch for Warning Signs: Report any pain, sensitivity, or swelling around the treated tooth to your dentist promptly. Most complications are easily managed if caught early.
Modern Advances in Root Canal Treatment
Endodontics continues to evolve with technological improvements that enhance treatment quality and patient comfort.
Digital Imaging and 3D Scans: Advanced imaging allows precise visualisation of canal anatomy before treatment begins, improving treatment planning and success rates.
Magnification and Illumination: Dental microscopes and high-powered lighting enable dentists to see intricate canal details, improving precision and allowing detection of small fractures or additional canals.
Rotary and Reciprocating Instruments: Modern motorised systems are more efficient and gentler on tooth structure than hand instruments alone, reducing treatment time and complications.
Biocompatible Sealers: New sealing materials, including bioceramic sealers, provide superior sealing properties and promote tissue healing.
Advanced Disinfection: Techniques like ultrasonic irrigation and photon-induced photoacoustic streaming enhance bacterial elimination from the root canal system.
These advances mean that root canal treatment today is faster, more predictable, and more comfortable than ever before.
Is Root Canal Treatment Right for You?
Your dentist is best positioned to determine whether root canal therapy is appropriate for your situation. However, generally speaking, root canal treatment is recommended when:
• Your tooth has a reversible or irreversible pulpitis (inflammation of the pulp)
• Your tooth has a necrotic (dead) pulp
• Your tooth has apical periodontitis (infection around the root tip)
• You wish to save your natural tooth rather than extract it
In some cases, if a tooth is severely compromised, extraction and replacement might be the better option. Your dentist will discuss the pros and cons of each approach based on your specific circumstances.
Key Takeaways
A root canal is a evidence-based, highly successful procedure that saves infected or damaged teeth and eliminates pain. Modern techniques and anaesthesia make the experience far less uncomfortable than its reputation suggests. With proper care and restoration, a root canal-treated tooth can function well for a lifetime.
If you're experiencing tooth pain or suspect you might need root canal treatment, don't delay—early intervention leads to simpler treatment and better outcomes. Your dentist can accurately diagnose your condition and discuss your options.
Important Disclaimer
The information provided in this article is for educational purposes only and should not replace professional medical advice. Symptoms described here require proper diagnosis by a qualified dentist. If you experience tooth pain, swelling, or other dental concerns, please consult your dentist or healthcare provider before beginning any treatment. Every individual's dental situation is unique, and what is appropriate for one person may differ for another. Always seek professional advice before undergoing any dental treatment.
