Toothache: The Most Common Causes and When to See a Dentist
Toothache is not a diagnosis. It is a symptom, and it may originate from the tooth, the gums, the bone, the jaw joint or even from outside the mouth. The type of pain, what triggers it and how long it has been present can provide important clues about what is causing it.
This article is intended to help you understand what your pain may be indicating and, above all, how urgently you should seek an assessment. It does not replace a dental appointment, because the same pain pattern can have different causes, and some of them can only be distinguished through clinical examination and X-rays.
The Same Pain, Very Different Causes
A tooth that hurts in response to cold for two seconds and a tooth that throbs continuously are signalling different problems. In the first case, the pulp may be inflamed but still viable. In the second, the inflammation may already be irreversible.
This distinction matters because it changes both the treatment and the window of time in which the problem can still be managed relatively simply.
One point is worth establishing from the outset: toothache that disappears on its own is not always good news. When a tooth that has been causing severe pain suddenly stops hurting for a few days, it may mean that the pulp is no longer vital. The problem has not resolved; there is simply no longer a functioning nerve to signal it.
Most Common Causes of Toothache
Tooth Decay
This is the most common cause. As long as the lesion remains within the enamel, it usually causes no symptoms. Once it reaches the dentine, sensitivity to cold, sweet or acidic foods may appear, usually brief and localised to a specific tooth.
As the decay approaches the pulp, the nature of the pain changes: it becomes more prolonged, more intense and less predictable. We have explained in another article how tooth decay develops and at what stage it may still be possible to stop its progression without a filling.
Inflammation of the Dental Pulp
The pulp is the tissue inside the tooth containing nerves and blood vessels. When it becomes inflamed, whether because of deep decay, trauma or a restoration positioned very close to the nerve, the rigid space in which it is contained does not allow it to swell.
This explains the intensity of the pain.
Irreversible pulpitis typically causes spontaneous, throbbing pain that may radiate towards the ear or temple and often becomes worse when lying down. It is one of the types of pain that most frequently leads people to seek emergency dental care.
Dental Abscess
When an infection spreads beyond the tooth and reaches the bone surrounding the root, a collection of pus may form. The pain is constant, the tooth becomes tender to touch and when chewing, and there is often a sensation that it feels higher than the neighbouring teeth.
Swelling may develop in the gum or face, together with an unpleasant taste if drainage occurs, and in some cases fever and general malaise. A dental abscess is one of the situations where delaying treatment can have more serious consequences, particularly when swelling spreads towards the neck or the eye.
Gingivitis and Periodontitis
Not all pain in the mouth comes from the teeth. Gum inflammation tends to cause diffuse discomfort, sensitivity during brushing and bleeding rather than severe, localised pain.
In periodontitis, where supporting bone has been lost, periodontal abscesses may develop and mobile teeth may become painful when chewing. We have written dedicated articles on gingivitis and periodontitis, including the signs that distinguish one from the other.
Gum Recession and Exposed Roots
The root of the tooth is not covered by enamel. When the gum recedes and exposes the root, temperature changes can reach the inside of the tooth much more easily.
The pain is typically short and sharp, triggered by cold, air or brushing, and is usually localised near the gumline. We have discussed the causes and progression of this problem in our article on receding gums.
Cracked Tooth or Fractured Restoration
A crack in a tooth can cause a very characteristic type of pain: a sharp sensation when the bite is released rather than while pressure is being applied.
It is often intermittent, difficult to pinpoint and may continue for months without being diagnosed.
Older fillings that fracture or become dislodged can expose the dentine and cause sudden sensitivity in a tooth that had previously been symptom-free.
Erupting or Impacted Wisdom Tooth
A wisdom tooth attempting to erupt without enough space may cause pain at the back of the jaw, often accompanied by inflammation of the flap of gum covering it, difficulty opening the mouth and pain radiating towards the ear.
The underlying issue is not only the acute episode. Wisdom teeth often have limited space and function within the dental arch, and retaining them may carry a risk of recurrent infections, decay in the tooth in front and pressure on neighbouring teeth. We have covered this subject in detail in our article on when a wisdom tooth should be removed.
Bruxism and Occlusal Overload
Clenching or grinding the teeth places excessive strain on the ligament supporting each tooth. The result is usually a diffuse, generalised pain, felt particularly upon waking and often accompanied by tiredness in the facial muscles.
The discomfort may seem to move from one tooth to another from day to day, which helps distinguish it from pain originating in the dental pulp. In another article, we discussed the causes and consequences of teeth grinding and the situations in which a dental appliance may help with bruxism.
When the Pain Is Not Coming from the Tooth
Not all pain felt in the teeth has a dental origin. Temporomandibular dysfunction may cause pain in the joint, the chewing muscles and frequently around the upper molars, together with clicking or other noises when opening the mouth and fatigue when chewing.
Diagnosis requires a targeted clinical assessment and includes CBCT, which allows the bony structures of the joint to be examined in greater detail than with a conventional X-ray. We have covered the symptoms and treatment in our article on temporomandibular dysfunction.
Maxillary sinusitis is another common source of confusion. The roots of the upper molars are located close to the maxillary sinus, and inflammation of the sinus can cause pain in several teeth at the same time. This pain often becomes worse when bending the head forwards and is usually accompanied by nasal congestion.
There are also neurological causes of facial and dental pain, such as trigeminal neuralgia, which produces a distinctive electric shock-like sensation.
What the Type of Pain May Suggest
This table is intended as a guide, not a diagnosis. Its purpose is to help you understand how urgently you may need to act.
Pain pattern | Most likely causes | Urgency |
Brief pain with cold or sweet foods, lasting only a few seconds | Early tooth decay, exposed root, enamel erosion | Appointment within the next few weeks |
Prolonged pain with heat, relieved by cold | Irreversible pulpitis | Priority appointment |
Pain when chewing or biting on a specific tooth | Crack, abscess, high restoration | Priority appointment |
Sharp pain when releasing the bite | Cracked tooth | Priority appointment |
Throbbing, spontaneous pain that worsens when lying down | Irreversible pulpitis | Urgent appointment |
Constant pain with swelling and tenderness to touch | Abscess | Urgent appointment |
Diffuse, generalised pain, worse on waking | Bruxism, occlusal overload | Appointment within the next few weeks |
Pain affecting several upper teeth at once, with nasal congestion | Sinusitis | Medical and dental assessment |
Pain at the back of the mouth with difficulty opening the jaw | Erupting wisdom tooth, pericoronitis | Priority appointment |
Pain triggered by heat that is relieved by cold is one of the patterns that most often surprises patients and is also one of the clearest indications that the pulp may be significantly compromised.
Warning Signs: When to See a Dentist Urgently
There are situations in which waiting for the next routine appointment is not appropriate.
Swelling of the face, neck or floor of the mouth. Fever associated with dental pain. Difficulty swallowing, breathing or opening the mouth. Severe pain that does not respond to usual painkillers. Trauma involving fracture or displacement of a tooth.
Progressive swelling is the most important warning sign on this list.
A dental infection that spreads into the spaces of the neck is no longer simply a dental problem and becomes a hospital emergency. This is uncommon, but it can occur and may progress rapidly.
What to Do While Waiting for Your Appointment
The aim during this period is to control the symptoms without masking or worsening the underlying problem. Using a commonly available painkiller, in accordance with the instructions on the packaging and taking into account any medication already prescribed for other conditions, may be reasonable.
Applying a cold compress to the outside of the face may help when inflammation is present. Keeping the head elevated at night can reduce throbbing pain in some cases. Continuing to clean the affected area carefully is preferable to stopping brushing because of discomfort.
There are three things to avoid, all of which still appear regularly in dental practice:
The first is placing aspirin or other tablets directly against the gum, which can cause a chemical burn to the tissue.
The second is applying heat to a swollen area, as this may encourage the infection to spread.
The third is taking leftover antibiotics from a previous treatment. Antibiotics do not resolve the underlying dental cause, and taking them without clinical indication can delay diagnosis and contribute to antimicrobial resistance.
How Is Toothache Treated? What to Expect at Your Appointment
The first step is to determine where the pain is coming from. This involves clinical examination, sensitivity and percussion tests and, usually, an X-ray, because much of what needs to be assessed is located inside the tooth or within the bone surrounding the root.
Treatment then depends on the cause. Tooth decay that has not reached the pulp can usually be treated with a filling. Irreversible pulpitis or pulp necrosis requires root canal treatment. An abscess requires drainage and treatment of the source of the infection, with antibiotics used only when there is a clinical indication.
Pain originating from the gums may require professional scaling. Muscular or joint pain follows a different pathway, involving assessment of the bite and, when appropriate, the use of a dental splint.
Relieving the pain without treating its source is only a temporary solution, and the interval before symptoms return is often short.
How to Prevent Toothache
Most episodes of toothache originate from conditions that have been developing silently for months or even years. Tooth decay does not usually hurt at the stage when it is easiest to treat. Gingivitis is almost always painless. A crack can develop without warning.
Brushing twice a day with fluoride toothpaste, cleaning between the teeth every day and attending regular dental assessments and professional cleaning appointments remain the main ways of preventing most of these problems.
Controlling tartar is also important, for the reasons we have explained in our article on what causes tartar to build up on the teeth. People with diagnosed bruxism may benefit from protection during the night. And those with older restorations benefit from regular assessments, because decay developing underneath them cannot always be seen with the naked eye.
When to Book an Appointment
If you have had tooth pain for more than one or two days, if it repeatedly returns in the same tooth, or if you are regularly taking painkillers just to be able to chew, it makes sense to arrange a dental assessment.
Toothache often follows a cyclical pattern, and it is common for the pain to disappear on its own after a few days. That does not mean the cause has resolved. In fact, the period between the pain subsiding and the next episode is often the best time to treat the problem before it becomes more complex.
