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Glendale, AZ 85308


Why do I have a Toothache?

Most of us have experienced a toothache before. In most cases, toothaches go away on their own, but once in a while they don’t. Sometimes toothaches are unbearable, and you should see your dentist immediately. But for those mild cases, where the pain is more nuisance than debilitating, how do you know when you should see your dentist?

Toothache Causes

Toothaches may be caused by a variety of factors, most of which are benign and will resolve on their own. Below is a non-comprehensive list:

  • Grinding / clenching teeth
  • Biting on something hard
  • Gum recession
  • Cavities
  • Cracks / fractured teeth
  • Broken filling / crown
  • Sinus infection
  • Tooth infection
  • Impact injury to the tooth
  • Gum disease
  • Muscle pain
  • Partially erupted teeth
  • Recent dental work
  • Orthodontics (braces,aligners, or retainers)
  • Bleaching / Whitening

As you can see, there are many possible causes of a toothache. As a dentist, it can be difficult to determine the cause of tooth pain, and even harder to identify the offending tooth. But, before you even bother seeing your dentist, these are the signs and symptoms that you should look out for:

  • Spontaneous, throbbing dull ache, especially when lying down
  • Pain when drinking hot fluids
  • Cold sensitivity that lingers for several seconds after drinking or eating something cold
  • Pus or drainage anywhere in the mouth
  • Broken or cracked teeth

Diagnosing Toothache

Large cavity
Large Cavity

Because there are so many possible causes of a toothache, your dentist will likely perform an examination with x-rays to determine the cause. They will probably ask you a lot of questions to try to better understand your symptoms.


Often, when patients are in extreme pain, dentists will perform a limited exam to address their specific complaint. If your pain is on the upper left, then x-rays will be taken of several teeth on the upper left, and your dentist will focus on those teeth.

My approach to diagnosing tooth pain may differ slightly from other dentists, but in general I start with the x-rays. When a patient is in a lot of pain, usually the offending tooth is immediately visible on the x-ray.

The cavity is indicated by the green arrow; the resulting abscess (infection) is indicated by the blue arrows
Partially impacted wisdom tooth causing cavity and infection
A partially impacted (horizontal) wisdom tooth has caused a large cavity and infection on the adjacent tooth

In the event there is no obvious problem on the x-rays, I will then perform an oral examination to see if I can spot any problems. In general, x-rays are great for spotting big things, and problems between teeth. But x-rays don’t see everything, so we still rely on our eyes for some diagnoses. A cavity like the one below may not be obvious on an x-ray, but is clearly visible to the eye.

Buccal cavity

Pulp Vitality Testing

Inside every tooth is a soft gooey tissue called pulp. The outside enamel of a tooth is the hardest part. Just under the enamel is another hard layer called dentin which is slightly softer than enamel. Beneath the dentin is the soft pulpal tissue at the center of the tooth.

Tooth Anatomy
Basic tooth anatomy

The pulp contains the blood supply and nerves of the tooth. This is why a painful cavity is a bad sign, because it means the cavity has penetrated to the heart of the tooth, a process that is irreversible. The kind of pain a patient is experiencing can be very informative for a dentist. If we identify a cavity through an x-ray or an exam, we will try to evaluate the health of the pulpal tissue through a variety of methods. A tooth with a cavity but no pain just needs a filling, but a cavity with pain probably needs root canal therapy.


One way to check a tooth is to tap on it with a blunt instrument. Your dentist will tap on several teeth and see if one of them hurts more than the others. This kind of pain indicates that the ligament surrounding the tooth is inflamed, much like a sprained ankle. This could be caused by an infection, or an injury to the tooth.

Periodontal Ligament (PDL) indicated by parallel lines surrounding the tooth

A healthy tooth is held into its socket by millions of elastic fibers that make up the Periodontal Ligament (PDL). This ligament is acts like a shock absorber, to prevent damage to teeth when biting into something hard. The PDL has nerves and can feel. When a tooth is injured or infected, the ligament can become painful. In fact, teeth that have been root canal treated can still experience pain from the PDL.


Your dentist may run their finger along the outside of an aching tooth to see if there is any pain where the tooth ends in your jaw. When there is pain in the jawbone around your tooth, this can be a sign of an abscess / infection at the end of the tooth. Sometimes, if an infection has been present for a long time, it will begin to drain out of the gum and form a blister.

Dental abscess


Healthy teeth have nerves inside the pulp tissue. These nerves allow our teeth to feel pain, temperature, pressure, and vibration. When the pulp tissue is unhealthy, the nerves may begin to die. When this happens, teeth may become sensitive to temperature changes.

There is more than one kind of nerve fiber inside each tooth, and the kind of temperature change the tooth perceives as painful can be very informative to a dentist. If the tooth is experiencing cold sensitivity that doesn’t linger, then there is a chance that the pulp tissue will recover and no further treatment is necessary. When a tooth reacts strongly to cold, and the pain sensation lasts more than a few seconds, then the pulp tissue is beginning to die. If heat provokes the pain, and cold makes the pain go away, then the tooth is in the final stages of pulpal death.

Electronic Pulp Testing

Electronic Pulp Tester (EPT)
Electronic Pulp Tester (EPT)

Sometimes, teeth don’t respond to temperature changes, especially in older patients. In these cases, some dentists will use a special instrument called an Electronic Pulp Tester (EPT) to see if the pulp of a tooth is alive. This instrument works by running electrical current through a tooth. The machine applies more current steadily over time to see if the patient feels anything. If the tooth does not respond to temperature changes or electrical currents, then the pulp has died and the tooth will need root canal therapy to treat or prevent infection.

Other Causes

In cases where there is no obvious cause for tooth pain, I will begin looking at other possible causes:

Sinus InfectionIf the patient has nasal drainage with sinus pain, then I may refer them to their PCP or an ENT for evaluation and treatment of a possible sinus infection.
Clenching / GrindingPatients who exhibit signs of clenching and grinding may need a mouth guard to protect their teeth as they sleep.
Gum RecessionIf I see signs of gum recession, then we may see if that is the cause of their sensitivity by blowing some air on the exposed tooth root.
Recent Dental WorkIf the patient has a recent filling, root canal, or crown, then I will assess the new restoration to see if it may be the cause of their toothache.
TraumaSometimes an injury to the face can result in a toothache years later. A blunt force injury can result in the death of one or more teeth, even when the teeth appear healthy.
Gum DiseaseInfections of the gum can cause infection and pain of the PDL which may feel like a toothache.
Muscle PainUsually caused by clenching and grinding, muscle pain can sometimes feel like a toothache.

Treating Toothache

The type of treatment needed to cure a toothache is as variable as the list of possible causes. I’ve tried to create a table that lists many of the common causes of toothache and their likely treatments:

Cavity with painRoot canal
Crack / fracture with painRoot canal or extraction
Infection of the toothRoot canal or extraction
Infection of the gumDeep cleaning, possibly gum surgery, rarely root canal
Traumatic injuryRoot canal
Partially erupted toothExtraction
Clenching / grindingMouth guard

Toothache in Children

Child Toothache

It’s hard enough to know when to see a dentist if your own tooth hurts, but what about your child? Children are a lot tougher than we give them credit for. In fact, they often don’t tell someone about a toothache until it is too late. This is why it is so important that children are seen regularly by a dentist, before reversible problems become permanent.

What are some of the classic signs and symptoms that a child may be experiencing tooth pain? Aside from actually telling you about it, kids may demonstrate some of the following behaviors:

  • Chewing on only one side
  • Holding the face
  • Complaining of pain when eating or drinking
  • Avoiding food entirely
  • Bad breath
  • Discoloration of the tooth
  • Pus / discharge

One complication when diagnosing children with tooth pain is whether they are in the process of gaining or losing teeth. If you are unsure, a visit to the dentist is probably the best course of action.


Toothache Dentist

Most toothaches go away on their own. In cases where your toothache persists, becomes unbearable, or is accompanied by one of the problem symptoms I described earlier, then you should see your dentist immediately. Rarely, dental emergencies can develop into serious medical emergencies. If you have reason to suspect that you may have an infection, you should see a dentist as soon as possible.

If your toothache was caused by a something you can identify like a popcorn kernel, or a sinus infection, then you may consider taking NSAIDs. I recommend Naproxen (Aleve) to my patients, as it is superior to Ibuprofen for dental pain and lasts longer between doses. Don’t travel with a toothache, it is never fun to have a full blown dental emergency on vacation. Lastly, if you do need dental treatment for your toothache, be as descriptive as possible to help your dentist nail the diagnosis!

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