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Why Is My Tooth Sensitive After a Filling? What Is Normal and What Is Not

A tooth that twinges with cold after a filling is normal, and that sensitivity fades over a week or two. Sensitivity that is severe, keeps getting worse or lingers after the cold has gone is a reason to call your dentist.

Side cross-section of a single upper molar with its three roots reaching up into porous jawbone and pink gum, a tooth-coloured filling in the biting surface, the pulp above the filling glowing pale blue, and wisps of cold air drifting towards the tooth from the left, on a navy to teal background

Here is why it happens, what eases it and which signs need a second look.

Key takeaways

  • Mild sensitivity is expected. A sore gum and a brief twinge from cold settle over a week or two.
  • A high bite can be adjusted. Your dentist can smooth down a filling that sits too high.
  • Getting worse is not healing. Pain that builds over days or throbs on its own needs a check.
  • Swelling needs a same-day call. Swelling, a fever or a lasting bad taste points to infection.

Is it normal for a tooth to be sensitive after a filling?

Yes. Mild sensitivity to cold and a sore gum around the tooth are normal after a filling and go away in a week or two.

Do not chew on that side until the freezing wears off, because a numb cheek is easy to bite. Once feeling is back you can eat as normal, since a tooth-coloured filling is set hard by a curing light before you leave the chair.

What you notice next is a short zing from a cold drink or cold air that fades within seconds.

Why does a filled tooth feel sensitive?

Diagram titled Why a New Filling Feels Sensitive showing a cross-section of a lower molar in pink gum and porous jawbone with a deep tooth-coloured filling, labelled New filling, Thin dentin layer, Irritated pulp, and Nerve and blood vessels
A deep filling leaves only a thin layer of dentin over the nerve.

The work itself irritates the nerve. Removing decay with a drill creates heat and vibration, and the pulp inside the tooth reacts with mild inflammation that settles as it heals.

How deep the cavity went matters most. Under the enamel sits dentin, a layer full of tiny channels that carry hot and cold signals towards the nerve. A deep filling leaves only a thin layer of dentin over the pulp, so cold reaches the nerve faster and the twinge takes longer to settle.

Two other causes are worth knowing:

  • A high spot. A filling that sits slightly proud takes extra force each time you bite and bruises the ligament that holds the tooth. Our post on why a tooth hurts when you bite down covers this pain in more detail.
  • A reaction to the material. An allergy to a filling material is rare. Tell your dental team and your doctor about a rash or itching near the tooth. Sudden swelling of your lips or tongue with a rash or itching is an emergency, so call 911.

How long does sensitivity last after a filling?

Mild sensitivity to cold should ease a little each day and fade within a week or two.

A tooth that feels the same after two weeks, or worse after a few days, has a cause that needs finding.

What can you do at home to ease the sensitivity?

Treat the tooth gently for a few days:

  • Choose lukewarm food and drinks. Very hot or iced drinks are the most common trigger.
  • Go easy on acidic food and drinks. Citrus fruit, pop and wine can sharpen the zing.
  • Use a toothpaste for sensitive teeth. Pastes with potassium nitrate are designed to calm the signal from the nerve.
  • Chew on the other side. Give the filled tooth a rest from hard and sticky food.
  • Take pain relief if you need it. Acetaminophen or ibuprofen helps if those medicines are safe for you.
New filling still sore after two weeks? Book an exam or call (905) 821-8632.

When is sensitivity after a filling a sign of a problem?

Cut-away lower molar between two neighbours with a large tooth-coloured filling close to a dark red inflamed pulp, a dark round area of infection in the bone at one root tip and redder gum beside the tooth, with a framed x-ray inset at the top right showing the bright white filling and a dark shadow at the root tip
An inflamed nerve under a deep filling, with infection at the root tip and an x-ray of the same tooth.

Sensitivity is a problem when it is severe or keeps getting worse. It points to a high bite, a failed filling or a nerve that cannot recover.

Call the clinic if you notice any of these:

  • Your bite feels high or uneven once the freezing wears off.
  • A twinge from cold or heat lasts long after you swallow.
  • Pain builds over several days instead of easing.
  • The tooth throbs on its own or wakes you at night.
  • The filling feels rough, cracked or loose.

Pain that lingers after something hot or cold can mean the nerve is badly inflamed and the tooth needs root canal treatment. A tooth that suddenly stops hurting has not healed either, because a dead nerve sends no pain while the infection at the root keeps going.

Swelling in your gum or face, a fever or a bad taste that will not shift means infection, so call us the same day. Keep heat off your face. When the clinic is closed, use an after-hours dental service and phone us once we open. Call 911 if you are drooling because you cannot manage your saliva or your voice sounds muffled.

Call 911 for trouble breathing or swallowing, heavy bleeding you cannot stop, confusion or fainting. Go to a hospital emergency department for swelling spreading to your neck, eye or under your tongue, a fever with facial swelling or a serious face, jaw or head injury. Our emergency page lists every other urgent sign to watch for.

What can your dentist do about a sensitive filling?

Top-down close view of three lower back teeth in pink gum, the middle molar with a new tooth-coloured filling marked by one dark blue dot, faint blue marks on the neighbouring teeth, a strip of blue marking paper held in steel tweezers and a white polishing tip on a dental handpiece next to the dot
Marking paper shows a high spot on a new filling as a dark blue dot.

The fix depends on the cause. Your dentist checks your bite and the filling and takes an x-ray if the nerve is in question.

  • Bite adjustment. You bite on a thin strip of marking paper, the high spot shows up as a dark mark, and the dentist smooths it down.
  • Repairing or replacing the filling. A filling with a crack or a gap at its edge is redone so it seals the tooth again.
  • Root canal treatment. When the nerve cannot recover, the inside of the tooth is cleaned and sealed, and most back teeth then need a crown.
  • Removing the tooth. An extraction is the last option.

Dentistry on Britannia in Mississauga bills insurers directly and gives you a written estimate before any new treatment starts. Regular checkups find decay while it is small, and a shallow filling is easier on the nerve.

Does your new filling feel too high? Book a visit or call (905) 821-8632.

Frequently asked questions

Is it normal for a tooth to hurt when biting after a filling?

A sore gum is normal for a week or two. A sharp pain each time you bite points to a high spot, so call and have your bite checked instead of putting up with it.

Why is my filled tooth still sensitive to cold weeks later?

Mild cold sensitivity should fade within a week or two. Sensitivity that stays the same or gets worse after that needs a check.

Do metal fillings cause more sensitivity than white fillings?

Metal carries heat and cold more readily than tooth-coloured composite, so a metal filling can pass temperature changes to the tooth faster. Composite is the standard choice at our clinic.