Lost a filling: what to do and how long you can wait

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Filling fell out? Here's what to do: take the piece out of your mouth (don't swallow it by accident), rinse with warm water, avoid chewing on that side and skip sweet, ice-cold or very hot foods, and book a visit within the next few days. With no pain, you can wait a few days — not weeks. With severe pain, sensitivity that won't go away or a root-canal-treated tooth that lost its filling, get seen right away.

In everyday practice, a filling rarely falls out “out of nowhere.” The most common causes are decay underneath it, old material that lost its bond, a fracture in the surrounding tooth or a bite that overloads that spot. In other words, the hole that's left is the visible sign of a problem that was already underway.

Dr. Cléo Salustiano (CRO-SP 170844), a dentist in Mooca, explains what to do in the first few hours, how long it's safe to wait, what counts as an emergency and how the filling is redone — and why, in some cases, it's replaced with a different solution.

This article comes from Dr. Cléo Salustiano's dental office in Mooca, São Paulo (care in English, Portuguese and Spanish). See the general dentistry page to learn how the treatment is done here and book your assessment.

Step by step

1. Take the piece out and rinse. Use warm water or saline. If the filling came out whole, keep it: it's rarely put back, but it helps the dentist understand what happened.
2. Don't use glue or try to put it back. Household glues are toxic to the tooth and gums and contaminate the cavity. The old filling won't bond again just by pressing it in.
3. Protect the cavity temporarily. A temporary filling material sold at pharmacies (a temporary filling kit) can cover the hole for a few days and reduce sensitivity. It's a stopgap: it doesn't clean out the decay underneath and doesn't replace a visit.
4. Change which side you chew on and what you eat. Avoid that side and hard, sticky and sugary foods. Extreme cold and heat tend to hurt because the dentin is exposed.
5. Keep the area clean. Brush gently and floss as usual. Food stuck in the cavity speeds up decay and inflames the gums.
6. Book a visit — and consider whether it's for today. Severe pain, intense sensitivity that doesn't improve, a root-canal-treated tooth with a post that lost its filling, or a sharp edge cutting your tongue: get seen the same day.

How long can I go without the filling?

The honest answer: days, not weeks. Without the filling, the dentin is exposed and starts collecting plaque in an area that's hard to clean. Decay, which was often already there under the material, progresses faster in this situation — and what was a simple filling can turn into a root canal or a crown.

With no pain and no sensitivity, about a week is usually a reasonable window for the visit. With sensitivity to cold, sweets or air, a few days is better: the constant stimulus inflames the nerve. With spontaneous pain — pain that appears without a trigger or wakes you up at night — the nerve is probably already inflamed, and that's an emergency.

Root-canal-treated teeth deserve special attention. They don't hurt, so a lost filling can go unnoticed, but they're more fragile and can fracture when you chew. If there was a post or a temporary crown, a fracture may mean the tooth can't be saved. Don't wait for pain: it won't warn you.

Another risk of waiting is shifting. Without contact with the neighboring tooth, the tooth can drift slightly over a few weeks, and the space starts trapping food. When the filling is finally redone, the dentist has one more problem to deal with.

A pharmacy temporary filling works as a bandage to get you through a few days — a trip, a weekend. It doesn't clean out the decay underneath, doesn't seal like a permanent material and tends to come loose. If it falls out, don't keep reapplying it: that's a sign the cavity needs treatment.

What does the dentist do when a filling falls out?

The first step is finding out why it fell out. A clinical exam and, when needed, an X-ray show whether there's decay underneath, whether the surrounding tooth has cracked, whether the bite is overloading that spot or whether the material simply aged.

When the tooth is intact and the decay is small, the usual solution is a new tooth-colored composite filling, done in the same visit. The cavity is cleaned, the decay is fully removed and the material is applied in layers and adjusted to your bite.

When a lot of tooth structure is missing, a regular filling may not hold up to chewing. Options such as an indirect restoration (made outside the mouth and cemented in) or a crown, which wraps around the tooth, come into play. The choice depends on how much healthy tooth is left, not on the size of the old filling.

If the decay reached the nerve or the tooth already had spontaneous pain, root canal treatment comes before the permanent restoration. After that, back teeth almost always get a crown, because they become more fragile.

For teeth with an old root canal that lost their filling, the assessment checks whether the treatment is still sound and whether the root is intact. Sometimes the root canal needs to be redone before rebuilding; with root fractures, extraction and planning a replacement may be the only option.

Once redone, a filling lasts longer with maintenance: regular check-ups, cavity prevention, a night guard for people with bruxism and care with very hard foods. No filling lasts forever, and follow-up is what keeps it from falling out again without warning.

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