Written by the Aspenwood Dental Team
Key Takeaways
- The signs most often linked to a root canal are sensitivity to hot or cold that lingers after the trigger is gone, pain when biting, a pimple on the gum, swelling, and a cracked or chipped tooth.
- A tooth can need a root canal without hurting at all. Some infections are found only on an x-ray.
- Swelling of the face or jaw, fever, or trouble breathing, swallowing or opening your mouth needs urgent care, not a wait for the next available appointment.
- Only an examination with pulp testing and x-rays can confirm whether a root canal is needed, or whether a smaller treatment will do.
The signs that you may need a root canal are pain when you chew or bite, sensitivity to hot or cold that lingers after the food or drink is gone, a pimple on the gum near a tooth, swollen or tender gums, a chipped or cracked tooth, and deep decay or darkening of the gum. That list comes from the American Association of Endodontists, the professional body for dentists who focus on the inside of the tooth. Any one of them is a reason to have the tooth examined. None of them on its own proves a root canal is needed.
There is also an important exception. A tooth can need a root canal and cause no pain at all. So the honest answer to the question is that symptoms are a reason to get checked, and an examination is what gives you the answer. At Aspenwood Dental Associates and Colorado Dental Implant Center, an independent practice in Aurora since 1972, that is how we approach it: we find out what is actually going on before talking about treatment.
What a root canal actually treats
Under the enamel and the hard dentin layer, every tooth has a core of soft tissue called the pulp, which contains blood vessels, nerves and connective tissue. The AAE explains that a fully developed tooth can survive without the pulp, because it continues to be nourished by the tissues around it.
A root canal is needed when that pulp becomes inflamed or infected. According to the AAE, the usual causes are deep decay, repeated dental procedures on the same tooth, faulty crowns, or a crack or chip. A blow to the tooth can also damage the pulp even when there is no visible crack. The treatment removes the inflamed or infected pulp, cleans and disinfects the inside of the tooth, then fills and seals it.
The signs, one by one
1. Sensitivity to hot or cold that lingers
With this sign, the detail is in how long it lasts. The AAE’s guide to tooth pain separates the two. Momentary sensitivity to hot or cold generally does not signal a serious problem. Lingering pain, typically lasting more than 30 seconds after the hot or cold food is gone, suggests the pulp may have been irreversibly damaged by deep decay or trauma.
2. Pain when you chew or bite
Pain when you bite down, or when the tooth is touched or tapped, can mean the inflammation has spread beyond the pulp into the tissue around the root tip. It can also be a sign of a crack. Either way, it is worth having checked rather than chewing on the other side indefinitely.
3. A pimple or bump on the gum
A small bump on the gum near a tooth, sometimes one that drains and comes back, can be the body’s way of letting pus escape from an infection at the root. MedlinePlus, the National Library of Medicine’s health site, describes swelling of the gum over an infected tooth that may look like a pimple. The bump may not hurt, and that can make it easy to ignore.
4. Swollen or tender gums
Swelling or tenderness in the gum around one particular tooth, rather than across the whole mouth, points toward a problem with that tooth. Swelling that spreads into the jaw or face is more serious, and it is covered in the urgent signs below.
5. A chipped or cracked tooth
A crack or chip can let bacteria reach the pulp, and the AAE lists it among the common reasons a root canal becomes necessary. A cracked tooth does not always hurt straight away, and some cracks are hard to see.
6. Deep decay or darkening
Decay that has reached close to the pulp, or darkening of the gum around a tooth, is on the AAE’s list as well. A tooth that changes color after an injury is also worth having examined.
7. Pain that spreads, or a loose tooth
Cleveland Clinic adds pain that spreads to the jaw, face or nearby teeth, a swollen jaw from a trapped infection, and a tooth that feels loose. Spreading pain can make it hard to tell which tooth is the source, which is one reason testing matters.
Can you need a root canal without any pain?
Yes. This surprises a lot of people. The AAE notes that an abscessed tooth may or may not be painful, and in its guidance to dentists on diagnosis it describes conditions where the pulp has died, or an infection has formed at the root tip, that produce no clinical symptoms and show up on an x-ray. A tooth whose pulp has died can stop responding and stop hurting, which can feel like the problem has settled when infection may still be present.
This is one of the practical reasons regular checkups and dental x-rays matter. A problem found on an x-ray before it hurts is usually easier to deal with than one found after a swelling.
When it is urgent
Most of the signs above call for a prompt appointment. A few call for urgent care the same day:
- Swelling of the face or jaw. MedlinePlus describes a swollen area of the upper or lower jaw as a very serious symptom.
- Swelling with fever or feeling generally unwell. The AAE describes fever, malaise and swollen lymph nodes as features of an acute abscess.
- Trouble breathing, swallowing, speaking or opening your mouth, or swelling that spreads toward your eye or neck. Health services such as the UK’s NHS advise emergency care for these. In the US, that means calling 911 or going to an emergency room.
MedlinePlus notes that an untreated abscess can get worse and lead to life-threatening complications. Our office hours are Monday to Friday, closing at 2:00 PM on Fridays and closed on weekends, so if any of these happen outside those hours, go to an emergency room rather than waiting for us to open. Our dental emergencies page and our post on what to do in a dental emergency with no dentist available in Aurora explain the options.
Signs that usually do not mean a root canal
Not every sensitive tooth is on its way to a root canal. A brief twinge from ice cream that fades within a few seconds, sensitivity across several teeth after using a whitening product, or soreness along the gumline from brushing too hard usually have other explanations. When inflammation of the pulp is mild and caught early, treating the cause, such as replacing a leaking filling, may be enough. Those are judgments to make after an examination, but they are a fair reason not to assume the worst.
How a dentist confirms whether you need one
Diagnosis is a set of comparisons rather than a single test. The AAE’s diagnostic guidance for dentists describes the usual steps, and the key principle is that every test is compared with the healthy teeth nearby:
- Pulp tests, usually cold and sometimes an electric pulp test, to see how the nerve responds and how long the response lasts.
- Tapping on the tooth and pressing on the gum over the root, to check for inflammation around the root tip.
- A bite test, which can help find a cracked tooth.
- X-rays from at least two angles, with a bitewing where needed, and in some cases 3D cone beam imaging for a clearer view of the roots and bone.
Putting those together tells your dentist whether the pulp is healthy, inflamed but likely to recover, irreversibly inflamed, or no longer alive, and whether there is infection around the root. That is what decides whether a root canal, a smaller treatment, or no treatment is the right call.
What happens if you wait
The AAE is direct about this on its root canal myths page: if a tooth infection is left untreated, it will not heal on its own. It can worsen, with more pain, swelling and an abscess, and in many cases delaying treatment can lead to losing the tooth.
The alternative to a root canal is usually removing the tooth. That is sometimes the right choice, for example when a tooth cannot be restored. But the AAE notes that an extracted tooth then needs replacing with an implant or a bridge to restore chewing and stop neighboring teeth from shifting. Where a tooth can be saved, keeping it is the option the AAE recommends. Our post on the downsides of having a dental bridge covers one of those replacement options.
What to expect if you do need one
The American Dental Association explains that your dentist uses local anesthesia so you do not feel the procedure. If dental anxiety has kept you away, ask about sedation options at your consultation.
Afterward, the tooth needs a lasting restoration. The AAE notes that teeth treated with a root canal, especially back teeth such as molars and premolars, often need a crown, while front teeth may not always need one. A treated tooth can occasionally fail to heal as expected or become reinfected, sometimes years later, and the AAE notes that in many cases it can be treated again through retreatment or endodontic surgery.
General dentist or endodontist?
Root canals are done by general dentists and by endodontists. The AAE explains that endodontists complete at least two extra years of training beyond dental school, focused on diagnosing tooth pain and treating the inside of the tooth. As the American Dental Association notes, a general dentist may refer a more complex case to an endodontist. If your tooth needs one, we will tell you who will treat it and why.
How Aspenwood checks a tooth that might need a root canal in Aurora
If you are new to us, your first visit is a complimentary consultation. You meet with a dentist first for a real conversation, then we examine the tooth, run the tests and take the imaging that is warranted, and explain what we found in plain terms. If a root canal is the right treatment, we will say so and tell you why. If a smaller treatment or no treatment is enough, we will tell you that too.
Before anything is scheduled, you will know what the treatment involves, whether the tooth is likely to need a crown afterward, and how payment works, with the options set out on our financial information and membership plan pages. Our first-visit comfort menu includes warm blankets, noise-canceling headphones and multiple sedation options. More detail on treatment is on our root canals page.
Frequently Asked Questions
Can you need a root canal and have no pain?
Yes. The American Association of Endodontists notes that an abscessed tooth may or may not be painful, and some teeth with a dead pulp or an infection at the root tip produce no symptoms at all and are found on an x-ray. A tooth whose pulp has died can stop hurting even though infection may still be present. This is one reason routine checkups and x-rays matter.
How do I know if tooth pain needs a root canal or just a filling?
You cannot tell for certain from the symptoms alone. One useful clue is timing: sensitivity to hot or cold that fades within a few seconds is often not serious, while pain that lingers for more than about 30 seconds after the trigger is gone suggests the pulp may be irreversibly damaged. A dentist confirms it with pulp tests, tapping and bite tests, and x-rays compared with your healthy teeth.
Can a tooth infection go away on its own?
No. The American Association of Endodontists states that an untreated tooth infection will not heal on its own and can worsen into more pain, swelling and an abscess, sometimes leading to tooth loss. Pain may come and go, but the source inside the tooth remains until it is treated with a root canal or the tooth is removed.
When is tooth pain an emergency?
Get urgent care the same day for swelling of the face or jaw, swelling with fever or feeling unwell, or any difficulty breathing, swallowing, speaking or opening your mouth. Call 911 or go to an emergency room for breathing or swallowing problems or swelling spreading toward the eye or neck. Outside our office hours, go to an emergency room rather than waiting for an appointment.
Do you always need a crown after a root canal?
Not always. The American Association of Endodontists notes that root canal treated back teeth, such as molars and premolars, often need a crown, while front teeth may not always need one. The decision depends on how much natural tooth remains and how much biting force the tooth takes. Delaying the final restoration is one of the reasons a treated tooth can become reinfected.
Is it better to get a root canal or pull the tooth?
When a tooth can be restored, keeping it with a root canal is generally the option the American Association of Endodontists recommends. Removing a tooth is sometimes the right choice, for example when it is cracked below the gumline or cannot be rebuilt. But an extracted tooth then needs replacing with an implant or a bridge to restore chewing and keep neighboring teeth from shifting.
Have a tooth that is sending you signals?
Book a visit and we will examine the tooth, run the tests that give a real answer, and walk you through every option before anything is scheduled. Reach us through the contact page or call (303) 529-2913. If you have facial swelling with fever or any trouble breathing or swallowing, go to an emergency room now.
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