Root Canal vs. Teeth Filling: Which One Do You Need?

Choosing between a root canal and a tooth filling can be a difficult question for patients to answer.

Both procedures fix damaged teeth. But they treat very different problems at very different stages of damage. 

According to the American Association of Endodontists, more than 15 million root canal procedures are performed every year in the United States. That makes it one of the most common dental procedures there is, yet it remains one of the most misunderstood.

What Is a Teeth Filling?

A dental filling is a straightforward restorative procedure used when a tooth has a cavity or minor structural damage that has not yet reached the inner pulp.

Here is what the process looks like:

• The dentist numbs the area around the tooth with local anaesthesia
• The decayed or damaged portion of the tooth is removed
• The space is cleaned and dried
• A filling material is placed into the cavity, composite resin being the most common today
• The filling is shaped, cured, and polished

The whole appointment typically takes 30 to 60 minutes. Most patients leave with no lingering discomfort beyond mild sensitivity for a day or two.

Types of filling materials:

• Composite resin (tooth-coloured, most commonly used today)
• Amalgam (silver-coloured, durable, less common now)
• Porcelain or ceramic (used for inlays and onlays)
• Gold (rarely used, but long-lasting)

Dental filling costs range from as low as $108 for silver amalgam fillings to as high as $1,774 for porcelain ceramic or gold fillings.

Also Read: Types of Dental Fillings: Materials, Costs & Pros and Cons

What Is a Root Canal?

A root canal is a bit more of an involved procedure. It becomes necessary treatment if decay or damage has moved past the outer layers of the tooth and into the pulp which is the soft tissue inside the tooth containing nerves and blood vessels.

The major difference is in how deep the problem goes. Fillings can treat the tooth structure. Root canals treat the pulp inside the tooth.

Here is a step-by-step description of the root canal process:

• The area is first numbed with local anaesthesia
• The dentist drills an opening in the top of the tooth
• The infected or inflamed pulp is removed
• The root canals are cleaned, shaped and disinfected
• The canals are filled with a rubber-like material called gutta-percha
• The tooth is sealed and in most cases a crown is placed on top to protect it further

The procedure usually takes one to two appointments depending on the severity of the infection.

According to a study published in Clinical Oral Investigations, the success rate of root canals exceeds 95% after 10 years. 

Root Canal vs. Filling: A Side-by-Side Look

How Do You Know Which One You Need?

Your dentist determines this through an examination and X-rays. But certain signs tend to point clearly in one direction.

Signs you likely need a filling:

• A cavity that your dentist spotted on an X-ray with no symptoms
• Mild tooth sensitivity to hot or cold that goes away quickly
• A small chip or crack in the tooth with no pain
• Early-stage decay that has not reached the pulp

Signs you likely need a root canal:

• Persistent, throbbing pain in the tooth, especially at night
• Sensitivity to hot or cold that lingers for more than a few seconds after the source is removed
• Pain when biting or applying pressure to the tooth
• Swelling or tenderness in the gums near the tooth
• A pimple-like bump on the gum near the affected tooth
• Tooth discolouration (the tooth turning dark or grey)

Not every cavity requires a root canal, but certain signs may indicate that the tooth needs more than just a filling. Persistent pain, especially when chewing or biting, and lingering sensitivity to hot or cold suggest the pulp is inflamed or infected, which requires treatment beyond a filling. 

What Happens If You Delay Treatment?

• This is where a lot of people make a costly mistake. A cavity that could have been fixed with a simple filling can progress to the point where a root canal becomes unavoidable if ignored long enough.
• If left untreated, decay can grow deeper. Eventually it may reach the inner nerve of the tooth, leading to infection. Once bacteria penetrate that inner pulp chamber, simple fillings will not fix the problem. 
• Beyond that, an untreated infection in the pulp can spread to surrounding bone and tissue, which can lead to an abscess. At that stage, extraction may become the only option.
• A filling avoided can eventually cost you a root canal. A root canal ignored can eventually cost you the tooth.

Cost Comparison

• The national average cost for a root canal is $1,165, but can range between $500 and $1,800. Most dental insurance plans cover 50% to 80% of the cost after the deductible is met.
• It is common for dental insurance plans to cover 50% to 80% of the cost of a root canal after the deductible has been met. Remember that a root canal also usually requires a crown afterward, which adds $800 to $3,000 to the total depending on material and location.

Frequently Asked Questions

Q1 What is the main difference between a filling and a root canal? 

A filling treats damage that stays within the outer tooth structure. A root canal is needed when the damage or infection has reached the pulp inside the tooth.

Q2 Is a root canal more painful than a filling? 

Both are performed under local anaesthesia. Most patients report that root canals are no more painful than getting a filling. The discomfort after treatment is usually manageable with over-the-counter pain relievers.

Q3 Can a tooth that needs a root canal be fixed with just a filling instead?

 No. Once the pulp is infected or irreversibly inflamed, a filling cannot address the problem. Only a root canal or extraction can resolve it at that stage.

Q4 How long does a filling last? 

Composite resin fillings typically last 5 to 10 years. Amalgam fillings can last 10 to 15 years or longer with good oral hygiene and regular dental visits.

Q5 How long does a root canal last?

With a proper crown placed afterward and good oral hygiene, a root canal-treated tooth can last a lifetime. The 10-year success rate exceeds 95%.