Sharp Pain After a Crown or Filling Comes Out: Is the Nerve Exposed?

A crown comes off in a piece of toffee, or a filling disappears while you are eating, and within minutes cold air produces a sharp, electric jolt through the tooth. The natural interpretation is that the nerve is exposed.

Usually it is not — at least not in the literal sense. What has almost always happened is that dentine has been uncovered, and dentine transmits stimuli to the pulp with remarkable efficiency. True pulp exposure, where the soft tissue inside the tooth is open to the mouth, is less common and behaves differently.

Distinguishing between the two matters, because they lead to different treatment.

Dentine is not solid. It is traversed by tubules — roughly 30,000 to 40,000 per square millimetre near the pulp — each containing fluid and, in the inner portion, a process extending from a cell body in the pulp.

The prevailing explanation of dentine sensitivity is hydrodynamic: a stimulus at the exposed surface causes rapid movement of fluid within the tubules, which deforms nerve endings at the pulpal end and is perceived as sharp pain. Cold causes fluid to contract and move outward; air drying causes evaporation; sweet or acidic substances create an osmotic gradient.

This is why the pain is characteristically sharp, immediate and short-lived, stopping within seconds of the stimulus being removed. It is a normal nerve responding normally to a surface that should be covered.

When a restoration comes out, thousands of tubules that were sealed are suddenly open. The intensity is a reflection of the area exposed, not necessarily of damage.

Exposed dentine: - Sharp pain triggered by cold, air, sweet things or touch - Stops within seconds of the trigger being removed - No spontaneous pain - Does not wake you at night - The cavity looks yellowish or brownish, with no red tissue visible

Exposed pulp: - Pain that lingers for minutes after a stimulus, or arises spontaneously - Throbbing rather than purely sharp - Often worse lying down - May wake you at night - May be poorly localised — you cannot identify which tooth - A red or bleeding point may be visible in the base of the cavity - Heat may provoke it, and cold may temporarily relieve it — a significant sign

The second pattern describes irreversible pulpitis, where the pulp is inflamed beyond recovery. It generally leads to root canal treatment or extraction. The first pattern describes an uncovered but otherwise healthy tooth, where restoring the surface resolves the symptoms.

Our article on root canal treatment for a broken tooth covers the assessment in more depth.

One caution: an exposed dentine surface left open does not stay uncomplicated indefinitely. Bacteria track down the open tubules towards the pulp. What begins as sensitivity can progress to pulpitis if the surface is left uncovered for weeks.

Decay at the margin. The commonest reason. The tooth underneath has broken down, so the restoration loses its foundation. This is why a crown that comes off may not simply be recementable.

Cement failure. Particularly on short or over-tapered preparations where retention depends heavily on cement.

Fracture of the remaining tooth. A cusp gives way and the restoration comes with it.

Fracture of the restoration. More common with older or large restorations.

Post failure in a root-treated tooth. The post and core come out with the crown, or the root itself fractures.

Sticky or hard foods. Usually the final straw rather than the cause.

Our articles on a lost crown while eating and a lost temporary crown cover the immediate situations.

Keep the restoration if you have it. Rinse it, keep it dry in a small container, and bring it. A crown in good condition on a sound preparation can sometimes be recemented.

Do not swallow or attempt to glue it back. Household adhesives are not appropriate in the mouth and can make proper recementation impossible. Temporary dental cement from a pharmacy is acceptable for short-term use and is designed to be removed.

Keep the area clean. Brush gently around the tooth. Debris packing into an open cavity causes pressure and worsens inflammation.

Avoid temperature extremes and chew elsewhere. Reduce the stimuli rather than testing the tooth.

A desensitising toothpaste helps. Applied directly to the exposed surface with a fingertip and left rather than rinsed, it can settle sensitivity within days by occluding tubules.

Analgesics as appropriate. Paracetamol or ibuprofen at standard over-the-counter doses, taken according to the packaging and your medical history. Do not place aspirin against the gum — it causes a chemical burn.

Seek same-day care if there is facial swelling, fever, difficulty swallowing or opening the mouth, severe pain not controlled by ordinary analgesia, or a tooth that has fractured to the gum line. Our emergency dental care page covers urgent appointments.

Assessment first. Examination and radiographs establish how much tooth remains, whether decay has undermined the preparation, and whether the pulp is involved. Sensibility testing helps distinguish a healthy pulp from a compromised one.

Recementation where the crown is intact and sits on a sound preparation with no decay.

A new restoration where decay has to be removed — often with a core build-up, then a new crown. Our article on core build-up requirements covers this stage, and crown options for a broken tooth covers the appointment sequence.

A direct restoration where a filling has been lost and the defect is moderate.

Root canal treatment where the pulp is irreversibly inflamed or has become infected. Our root canal treatment page covers the procedure.

Extraction where the fracture extends substantially below the gum or into the root and there is not enough sound structure to retain a restoration. Our article on crown versus extraction covers that decision.

• Clean restoration margins thoroughly, including interdentally — decay at the margin is the commonest reason restorations fail

• Attend regular examinations so marginal breakdown is found before the restoration comes out

• Wear a night guard if you grind. Our night guards page covers this

• Avoid chewing ice, boiled sweets, pen lids and packaging

• Report any tooth that has become sensitive or feels different, rather than waiting for something to come out

• Sharp pain after a restoration comes out is usually uncovered dentine, not an exposed pulp.

• Dentine pain is sharp, immediate and stops within seconds; pulpal pain lingers, arises spontaneously and disturbs sleep.

• Heat provoking pain and cold relieving it is a significant sign suggesting the pulp is involved.

• An uncovered surface left for weeks can progress to pulpitis, so the situation is time-sensitive.

• Keep the restoration, do not use household glue, and keep the area clean.

• Desensitising toothpaste applied directly and left on provides interim relief.

Can a lost crown be recemented?

Sometimes. It depends on whether the crown is intact, whether the preparation underneath is sound, and whether decay has developed. If the tooth beneath has broken down, a new restoration is usually needed.

How long can I wait before being seen?

It is best not to wait long. An uncovered surface allows bacteria to track towards the pulp, and the surrounding teeth can drift so that the restoration no longer fits. Days are usually acceptable; weeks are not.

Is sensitivity after a crown falls off normal?

Yes. The preparation underneath has exposed dentine, which is highly sensitive to cold and air. Sharp, brief sensitivity is expected. Pain that lingers or arises without a trigger is different and should be reported.

Can I use temporary cement from a pharmacy?

Yes, for short-term use until you are seen. It is designed to be removable. Do not use superglue or any household adhesive, which can prevent proper recementation and cause soft tissue injury.

What if the nerve becomes infected?

If the pulp becomes irreversibly inflamed or necrotic, root canal treatment is usually needed to retain the tooth. Left untreated, infection can spread into the surrounding bone. Our article on signs of infection spreading covers the warning signs.

Why did my restoration come out in the first place?

Most commonly because decay developed at the margin and undermined the tooth beneath. Other causes include cement failure, fracture of the remaining tooth structure, and fracture of the restoration itself.

If a crown or filling has come out, prompt assessment establishes whether it can be recemented and whether the pulp is involved.

You can contact our team at our Wimpole Street practice, or read about our emergency dental care and white fillings.

This article provides general information about pain following the loss of a dental restoration and does not constitute individual dental advice. The cause of tooth pain and the appropriate treatment require clinical assessment including radiographs and sensibility testing. If you have facial swelling, fever or difficulty swallowing, seek urgent care. Wimpole Dental is regulated by the Care Quality Commission, and our clinicians are registered with the General Dental Council.

Next review due: 18 September 2027