Reviewed by Dr. Manish Pandey, BDS, FAGE (Manipal University)
Last medically reviewed: August 14, 2026
Tooth sensitivity after a filling is common, especially when the cavity was deep. Mild, brief discomfort with cold, sweetness or pressure often settles as the tooth recovers. Pain that is worsening, spontaneous, lingering after heat or cold, or associated with swelling needs a dental review because it may indicate a high filling, pulp inflammation, a crack or infection.
Quick answer: how long should sensitivity last?
Some sensitivity can last from a few days to a few weeks. The American Association of Endodontists notes that recent dental work can temporarily inflame the pulp and advises assessment if pain persists or worsens. The important trend is improvement: symptoms should become milder and less frequent, not steadily more intense.
Why can a filled tooth become sensitive?
1. Temporary pulp irritation
Removing decay and preparing a cavity transmits heat, vibration and pressure through dentine. A deep filling also sits closer to the pulp, the living tissue containing nerves and blood vessels. Mild inflammation may cause short sensitivity to cold or air while the pulp settles.
2. The filling is slightly high
If the restoration contacts first when you close your teeth, the tooth and its supporting ligament receive extra force. The bite may feel uneven, and pain is often most noticeable when chewing. A dentist can check the bite with marking paper and make a small adjustment. Do not try to file the filling yourself.
3. Deep decay or irreversible pulpitis
A very deep cavity may have already inflamed or infected the pulp before treatment. Warning patterns include spontaneous throbbing, pain that wakes you, or hot or cold pain that lingers well after the trigger is removed. The tooth may require further pulp testing and sometimes root canal treatment rather than another filling.
4. Bonding shrinkage, leakage or an open contact
Tooth-coloured composite is bonded in layers. Stress at the tooth–filling interface or a marginal gap may allow fluid movement and sensitivity. If the contact between neighbouring teeth is open, food can pack into the space and irritate the gum. Persistent problems may require repair or replacement.
5. A crack in the tooth
A tooth weakened by a large cavity may contain a crack that becomes symptomatic after restoration. Sharp, unpredictable pain during chewing—particularly on release—can be a clue. Read our guide to cracked teeth and the focused guide to pain when biting.
What type of post-filling pain matters?
- Brief cold sensitivity: often temporary if it is improving.
- Pain only when biting: may indicate a high filling, loose restoration or crack.
- Lingering hot or cold pain: can suggest more significant pulp inflammation.
- Spontaneous or night pain: needs prompt evaluation.
- Swelling, fever or bad taste: may indicate infection and requires urgent care.
Safe steps while you arrange a review
- Avoid very hot, cold or hard foods for a short period.
- Chew on the other side if pressure triggers pain.
- Brush gently with fluoride toothpaste and keep the area clean.
- A desensitizing toothpaste may help exposed dentine, but it will not correct a high filling, crack or inflamed pulp.
- If safe for you, use an over-the-counter pain reliever only as directed on the label or by a clinician.
Do not place aspirin, crushed medication, undiluted clove oil, bleach or concentrated peroxide on the tooth. Do not start leftover antibiotics. Antibiotics do not correct a high bite or repair a filling and are not appropriate for most localized dental pain without systemic infection.
When should you contact the dentist?
Contact the treating dentist if your bite feels uneven, sensitivity is worsening, pain persists without improvement, the filling chips, or food repeatedly traps around it. Seek urgent assessment for facial swelling, fever, pus or a bad taste with pain, difficulty opening the mouth, or severe spontaneous pain.
Breathing or swallowing difficulty, rapidly spreading face or neck swelling, eye swelling or serious deterioration requires emergency medical care.
How the dentist finds the cause
The dentist will review when the pain started and what triggers it, inspect the restoration, check the bite, tap the tooth, examine the gums and test the pulp response to cold. Dental X-rays may help assess depth of the filling, decay and tissue around the root, although a fine crack is not always visible. Treatment may involve reassurance and monitoring, bite adjustment, repair or replacement of the filling, protection with an onlay or crown, or root canal treatment when the pulp cannot recover.
Frequently asked questions
Is cold sensitivity normal after a filling?
Mild, brief cold sensitivity can be normal and should gradually improve. Lingering, severe or worsening pain needs an examination.
Why does the tooth hurt only when I chew?
A slightly high restoration is a common possibility, but a loose filling, crack or inflammation around the root can produce similar symptoms. A bite check is needed.
Does sensitivity mean I need a root canal?
No. Many teeth recover after a filling. Root canal treatment is considered when symptoms and testing show that the pulp is irreversibly inflamed or infected.
Should an intact amalgam filling be removed for health reasons?
The US FDA does not recommend removing an intact amalgam filling solely to prevent disease when there is no decay beneath it, because removal sacrifices healthy tooth structure and temporarily increases mercury-vapour exposure. Discuss individual risks and alternatives with your dentist.
Authoritative references
- American Association of Endodontists: Tooth Pain
- Healthdirect Australia: Dental Fillings
- US FDA: Information for Patients About Dental Amalgam Fillings
- Cleveland Clinic: Dental Fillings
Dental disclaimer: This article is for general education and cannot diagnose an individual tooth. Contact a dentist for persistent or worsening symptoms and seek emergency care for breathing or swallowing difficulty or rapidly spreading swelling.