Lost Filling or Crown: What to Do Before It Gets Worse

The tooth underneath is now unprotected. That is the whole reason this cannot sit for a month.

Table of Contents

1. What to Do When You Lose a Filling
2. Why It Came Out
3. How Urgent Is It?
4. What Not to Use to Stick It Back
5. Protecting the Tooth Until You Are Seen
6. What the Repair Involves
7. FAQs About a Lost Filling

You bit into something and there is now a small hard object in your mouth that is not food, or your tongue has found a crater where a filling used to be. It rarely hurts immediately. That is exactly why people leave it. A lost filling exposes the inner layers of the tooth to bacteria, temperature, and biting force. The tooth is weaker than it was and the cavity underneath grows quickly. Getting it recemented or refilled within a week or two usually keeps the repair simple.

What to Do When You Lose a Filling

Five steps. None of them take long.

1. Find and keep the piece. A crown can very often be recemented. A filling cannot be reused, and bringing it still helps.
2. Rinse your mouth with warm salt water to clean the area.
3. Call the office on (208) 356-5601 for an appointment within a few days.
4. Avoid chewing on that side entirely until it is repaired.
5. Cover the cavity with temporary dental cement from a pharmacy if the edge is sharp or sensitive.

Do not attempt to glue a crown back yourself with anything from a household drawer. The reasons are below and they are serious. If there is significant pain, swelling, or a bad taste, call the same day. That combination points toward an infection under the restoration rather than a simple loss.

Why It Came Out

There is almost always a reason, and it changes what the repair needs to be. Decay underneath. The most common cause. The tooth around the filling has broken down, so there is nothing left to hold it. A new filling of the same size will not stay either. The filling was old. Restorations do not last forever. Margins wear, seals leak, and the bond eventually gives. A crack in the tooth. Flexing under bite load breaks the seal and eventually pushes the restoration out. Sticky food. Caramel and toffee are the immediate cause fairly often, and they usually only succeed against something already weakened. Grinding. Repeated overload fatigues both the tooth and the restoration. Cement failure on a crown. Sometimes the crown and tooth are both fine and the cement has simply washed out over years. That last one is the good outcome. It usually means a clean recementation.

How Urgent Is It?

Not an emergency in most cases, and not something to sit on either.

Situation	How soon
No pain, no sharp edge	Within one to two weeks
Sensitive to cold or air	Within a few days
Sharp edge cutting your tongue	Within a few days
Front tooth, visible	Within a few days
Severe pain, swelling, bad taste	Same day
Crown off and you have the crown	Within a week, keep it safe

The reason for the two-week outer limit is straightforward. Exposed dentine decays far faster than enamel, and a cavity that would have needed a filling can need a crown or a root canal after a few months of exposure. People routinely arrive having waited six months with no pain and are surprised the repair is no longer small.

What Not to Use to Stick It Back

This section exists since people genuinely do these things. Never use superglue. It is toxic in the mouth, it bonds unevenly so the crown seats wrong, and it makes proper recementation far harder or impossible. A crown that could have been recemented for a small fee becomes a new crown. Never use chewing gum, wax, or putty long term. Fine for an hour to cover a sharp edge, not fine as a plan. Never use household adhesives of any kind. Do not force a crown back on if it does not seat easily. It usually means something is in the way, and forcing it can fracture the tooth underneath. The one acceptable temporary is over-the-counter temporary dental cement, sold at most pharmacies for exactly this. It is designed to come off cleanly. Read the packet, use a small amount, and treat it as a bridge to the appointment rather than the repair.

Protecting the Tooth Until You Are Seen

A few days of care usually prevents a small problem becoming a bigger one. Keep it clean. Brush the area gently. Food packing into an open cavity accelerates decay and causes most of the discomfort. Rinse after eating. Warm salt water, or just water. Avoid extremes. Very hot and very cold both provoke exposed dentine. Skip sticky and hard food. Both on that side and usually, since a weakened tooth is easy to break further. Store a crown safely. In a small container, not a tissue, and bring it to the appointment. Watch for change. Increasing pain, sensitivity that lingers after cold, or any swelling means calling sooner. Our post on dental abscess signs covers what to look for.

What the Repair Involves

It depends on what is left of the tooth. Recementing a crown. The crown and tooth are cleaned, the fit checked, and it is cemented back. Usually one short appointment with no anesthetic. This is the best case and it is common. A new filling. Where decay has been removed and enough sound tooth remains. One appointment. A crown instead of a filling. Where the cavity is now too large for a filling to hold. Two appointments, covered in our getting a crown post. A root canal first. Where decay has reached the nerve, or where the tooth was already close to it. Extraction. Only where too little sound structure remains to restore. Uncommon when the problem is dealt with early. An X-ray is taken to see how deep the decay goes, which is what determines which of these applies.

FAQs About a Lost Filling

Is a lost filling a dental emergency? Not usually. It becomes one with severe pain, swelling, or a bad taste, which suggest infection. Otherwise aim to be seen within one to two weeks, sooner if the tooth is sensitive or the edge is sharp. The tooth is unprotected in the meantime and decays faster than usual. Can I put my crown back myself? Only temporarily, with over-the-counter temporary dental cement from a pharmacy, and only if it seats easily without force. Never use superglue or household adhesive. Superglue is toxic in the mouth and frequently ruins a crown that could otherwise have been recemented cheaply. How long can I leave a lost filling? One to two weeks is a reasonable outer limit with no symptoms. Exposed dentine decays much faster than enamel, so waiting months regularly turns a filling into a crown or a root canal. Lack of pain is not evidence that nothing is happening. Why does my tooth hurt more now the filling is gone? Since the dentine underneath contains microscopic tubes running toward the nerve, and it reacts sharply to cold, air, and sweet things once uncovered. Sensitivity that stops quickly is expected. Pain that lingers for minutes afterward suggests the nerve is inflamed and needs assessing. Will I need a new crown or can the old one be reused? Often the old one goes straight back on, particularly where the cement simply failed. A new crown is needed where the crown itself is damaged, where decay has changed the shape of the tooth underneath, or where the fit is no longer accurate.

Book It Before It Grows

A recementation or a small filling now is a far shorter appointment than a crown or a root canal in six months. Call (208) 356-5601 or see our emergency dental page. Madison Park Dental, 345 N 2nd E Ste 2, Rexburg, ID 83440. Rated 4.9 stars across 229 Google reviews. Reviewed by Dr. Matthew Griffeth, Madison Park Dental. This article is general information, not dental advice.