A cracked or broken filling is rarely a true emergency, but it is not something to leave indefinitely. The usual first clue is a change you can feel: new sensitivity to hot, cold or sweet, a rough or sharp edge your tongue keeps finding, or a twinge when you bite down. Sometimes you feel or even hear the moment a filling fractures. The reason it matters is that a gap between the filling and the tooth traps bacteria you cannot clean out, which can lead to decay underneath. Getting it checked within a few days usually keeps the fix simple.
Here is what to look for, why it happens, and what to do before your appointment.
Key takeaways
- Common signs are new sensitivity, a rough or sharp edge, and pain when biting.
- You may notice a dark line, a visible gap, or a piece missing from the filling.
- A cracked filling is usually not an emergency, but it should be seen within a few days.
- The risk is decay under the filling, because the gap traps bacteria you cannot brush away.
- Avoid chewing on that side and do not use household glue to stick anything back.
Why fillings crack or break
Fillings take the same forces as your own teeth, day in and day out, and no filling lasts forever. Over years, the repeated stress of chewing can fatigue a filling, especially a large one. Biting on something hard, grinding or clenching at night, or decay creeping in at the edge can all weaken it until it chips, cracks or partly falls out. Our guide to how long fillings last covers the lifespan you can reasonably expect.
Signs your filling may be cracked
| Sign | What you may notice |
|---|---|
| New sensitivity | Sharp reaction to hot, cold or sweet that fades quickly |
| Rough or sharp edge | Your tongue keeps catching on the tooth |
| Pain on biting | A twinge or ache when you chew on that tooth |
| Visible change | A dark line, a gap, or a missing piece of filling |
| Food trapping | Food repeatedly packs into the same spot |
Sensitivity that fades quickly is usually a warning sign rather than an emergency. Pain that lingers after the trigger is gone, wakes you at night, or comes with swelling suggests the problem has reached the nerve and needs prompter attention, as covered in our guide to reversible versus irreversible pulpitis.
Why a cracked filling matters
The concern is not just discomfort. When a filling cracks, a tiny gap opens between it and the tooth. Bacteria and food work into that space, which you cannot reach with a brush, and decay can start underneath where you cannot see it. Left long enough, that hidden decay can grow until a simple replacement filling is no longer enough and the tooth needs an onlay, a crown, or in worse cases root canal treatment. Catching it early is what keeps the repair small.
What to do before your appointment
A cracked filling usually gives you a few days, so there is no need to panic, but a few steps help in the meantime. Chew on the other side to keep pressure off the tooth, keep the area clean with gentle brushing, and rinse with warm salt water if the gum is tender. Manage any discomfort with over-the-counter pain relief as directed. If a piece has come away and the edge is sharp, dental wax or sugar-free gum can cover it temporarily. Do not use superglue or any household adhesive to stick a piece back, as these are not safe in the mouth and make the proper repair harder. If a filling falls out completely, our guide to a filling falling out walks through the steps.
How it is repaired
Treatment depends on how much of the filling and tooth is affected. A small crack usually means removing the old filling and placing a new one. A larger break may need an onlay or crown to cover and protect the tooth, and if decay or a crack has reached the nerve, root canal treatment may be needed first. The earlier it is seen, the more likely the simple option is enough.
Frequently asked questions
Is a cracked filling a dental emergency?
Usually not. Most cracked fillings can wait a few days for an appointment. Seek prompt care if you have severe or lingering pain, swelling, or a sharp edge cutting your tongue or cheek.
Can I still eat with a cracked filling?
Yes, but chew on the other side and avoid hard, sticky or very hot and cold foods on that tooth until it is repaired, to reduce sensitivity and further damage.
What happens if I leave a cracked filling?
Bacteria enter the gap and can cause decay under the filling. Over time this can turn a simple repair into a larger one, such as a crown or root canal treatment.
Can a cracked filling be repaired or does it need replacing?
Most cracked fillings are replaced rather than patched. If the tooth is significantly weakened, an onlay or crown may be recommended instead of another filling.
Why is my tooth sensitive after the filling cracked?
The crack exposes the inner tooth to temperature and sweetness. Brief sensitivity is common, but pain that lingers or worsens should be checked promptly.
The takeaway
A cracked filling usually shows up as new sensitivity, a rough edge or pain on biting, and while it is rarely an emergency it should be seen within a few days before decay starts underneath. Keep the tooth clean, chew on the other side, and avoid household glue. To get it looked at, see our current offers or visit our general dentistry page.
This article is general information and not a substitute for an individual dental assessment.
