Root Canal: What It Is, When It’s Needed & How to Prevent It

Patient-friendly guide from a clinical perspective, including when antibiotics are (and aren’t) appropriate, what to expect at the dentist and how to reduce your risk of ever needing a root canal.

Key Points

• A root canal (endodontic treatment) removes infected tissue (“pulp”) from inside the tooth, disinfects the canals, and seals them to save the tooth.

• It’s usually recommended for deep decay, cracks, or trauma that has reached the pulp and caused irreversible pulpitis or a dental abscess.

• Antibiotics alone don’t cure a dental abscess or replace dental treatment. They’re used only when there are signs of spreading infection or systemic illness, or when immediate drainage isn’t possible.

• The goal is source control: remove infection inside the tooth and prevent it from spreading or returning.
  
  

Do I need a root canal and why?

You may need a root canal when bacteria enters the pulp (through decay, a fracture, or a leaking filling) and the tissue becomes inflamed or infected. 

Typical reasons your dentist recommends it include:

• Persistent toothache, especially on biting or with hot/cold.
• Prolonged sensitivity, swelling, tenderness to touch, or a gum boil (sinus tract).
• X-ray evidence of infection at the tip of the root (periapical radiolucency).
• A dental abscess arising from the tooth.

Left untreated, infection can cause worsening pain, facial swelling and, rarely, more serious complications.

Are antibiotics needed before a root canal?

Not routinely. UK guidance is clear: for most dental abscesses, local treatment (drainage, root canal, or extraction) is definitive. 

Antibiotics are adjuncts reserved for:

• Spreading infection (cellulitis, lymph node involvement).
• Systemic features (fever, malaise) or high-risk patients (such as those who are immunocompromised).
• Situations where immediate operative care isn’t possible and temporary control is needed pending urgent dental treatment.

In the UK, antibiotics such as amoxicillin are prescription-only and should follow a clinician’s assessment. Responsible providers focus on a condition-led consultation and urgent dental treatment rather than “antibiotics first”.

What happens before a root canal?

1. Assessment & X-rays: Your dentist examines the tooth, checks vitality, and takes an X-ray to plan treatment.

2. Consent & plan: You’ll discuss options (root canal vs extraction), risks, benefits, costs, and the likely need for a crown on back teeth after treatment.

3. Pain control: Local anaesthetic is used; you should feel pressure, not pain.
   
   

Step-by-step: What happens during a root canal

1. Isolation: A rubber dam is placed to keep the area clean and protect your airway.

2. Access: A small opening is made in the tooth to reach the canals.

3. Cleaning & shaping: Infected pulp is removed and canals are disinfected with antibacterial solutions; files shape the canals for sealing.

4. Medication (if needed): Sometimes an antibacterial dressing is placed between visits.

5. Sealing (obturation): Canals are sealed with a biocompatible material (e.g., gutta-percha) and the access is filled.

6. Final restoration: A permanent filling or crown restores strength and seals the tooth against reinfection.

Appointments typically last 60–90 minutes; some cases need more than one visit (complex roots, large infections).

If you also have a dental abscess…

Your dentist will ensure drainage (through the tooth or via a small gum incision if needed). This relieves pressure and helps infection resolve. Antibiotics are added only when indicated (see above).

Recovery and aftercare following a root canal

• Pain relief: Discomfort usually improves within 24–48 hours; take simple analgesia (e.g., paracetamol/ibuprofen if suitable for you) as advised.

• Diet & hygiene: Soft foods for 1–2 days; brush as normal, keep the area clean.

• Protect the tooth: Avoid hard biting until the final crown is fitted (back teeth are prone to fracture without a crown).

• When to call back: If pain/swelling worsens, you develop fever, or the temporary filling comes out.
  
  

Risks, success rates, and alternatives to root canals

• High success rate when canals are thoroughly cleaned and the tooth is well restored.

• Possible risks: persistent infection requiring re-treatment, fracture if not crowned, or (less commonly) extraction if the tooth can’t be saved.

• Alternative: Extraction ends infection faster but leaves a gap; you may later consider an implant/bridge.
  
  

How to prevent root canals

• Brush twice daily with fluoride toothpaste (spit, don’t rinse).
• Clean between teeth (floss or interdental brushes).
• Limit free sugars, especially between meals and before bed.
• Regular check-ups with your dentist/hygienist to spot and treat decay early.
• Don’t ignore cracked fillings or tooth injuries and seek prompt care.
  
  

Urgent “red flags”:  seek same-day help (A&E/urgent dental)

• Swelling under the tongue/floor of mouth, trouble swallowing or breathing, and trismus (can’t open mouth).

• High fever, rigors, confusion, rapidly spreading facial swelling.

• You feel very unwell or are immunocompromised.

Author: Dr Javeria Kiran Ahmed 

Credentials: Dental Surgeon (GDC No. 244004), Qualified from University of Bristol 2013, BDS. Specialist Interest: Restorative Dentistry, Occlusion, Treatment of Complex Dental Cases, Facial Aesthetics, and Clear Braces