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Treatment Comparison

Lost Filling vs Lost Crown: What's the Difference and What Should You Do?

Whether a filling has fallen out or a crown has come loose, knowing the difference helps you act quickly and get the right care.

Losing a filling or a crown can be uncomfortable and unsettling — but the two situations are not the same. The level of urgency, the risk to your tooth, and the treatment required can differ considerably.

This guide explains the key differences so you can take the right steps quickly. Whether you need a simple replacement filling or emergency crown re-cementation, understanding your situation helps you make an informed decision.

Treatment suitability always depends on individual clinical assessment. The information below is for general guidance only.

Quick Comparison

Lost Filling vs Lost Crown at a Glance

Type of restoration

Filling

Fills a cavity within the tooth structure

Crown

Covers and encases the entire visible tooth

Severity of exposure

Filling

Inner tooth exposed — risk of sensitivity and decay

Crown

Prepared tooth stump exposed — vulnerable to fracture

Pain risk

Filling

Moderate — sensitivity to hot, cold, and sweet

Crown

Moderate to high — sharp edges may irritate tongue and gums

Urgency level

Filling

Should be seen within a few days

Crown

Should be seen as soon as possible — ideally within 24–48 hours

Temporary solutions

Filling

Over-the-counter temporary filling material

Crown

Temporary dental cement or denture adhesive to re-seat crown

Long-term fix

Filling

New composite or amalgam filling; onlay if extensive

Crown

Re-cementation if crown is intact; new crown if damaged

Indicative cost (UK)

Filling

From approximately £92.50*

Crown

From approximately £495*

Risk if untreated

Filling

Decay progression, possible infection, tooth fracture

Crown

Tooth fracture, shifting bite, infection of the prepared tooth

*Indicative prices. Final costs depend on clinical findings. See full treatment fees.

Understanding the Issue

What Is a Lost Filling?

A dental filling restores a tooth after decay has been removed. When a filling falls out, the cavity is left exposed — creating a space where bacteria and food debris can accumulate rapidly.

Common Causes

  • Normal wear over time — composite and amalgam fillings have a finite lifespan
  • New decay forming around the edge of the existing filling
  • Biting on something hard or sticky that dislodges the material
  • Teeth grinding (bruxism) placing excessive stress on the restoration

Risks of Leaving It Untreated

  • Accelerated tooth decay in the unprotected cavity
  • Increased sensitivity to temperature and pressure
  • Bacterial infection potentially reaching the tooth nerve
  • Weakened tooth structure, increasing the risk of fracture

Treatment Options

Your dentist will assess the remaining tooth structure to determine the most suitable approach. Options typically include:

  • Direct composite filling — tooth-coloured material bonded in a single visit
  • Amalgam filling — durable option for posterior teeth
  • Inlay or onlay — a lab-made restoration for larger cavities
  • Crown — recommended when the remaining tooth structure is insufficient for a filling
Understanding the Issue

What Is a Lost Crown?

A dental crown is a cap that fits over a damaged or heavily treated tooth — often one that has had a root canal. When the crown detaches, it leaves the prepared tooth stump exposed and vulnerable.

Common Causes

  • Cement failure — dental cement weakens over time
  • Decay developing underneath the crown at the margin
  • Trauma or biting on extremely hard foods
  • Poor fit or age-related wear of the crown

Risks of Leaving It Untreated

  • Fracture of the prepared tooth — often beyond repair
  • Rapid contamination of a root-treated tooth
  • Bite misalignment as adjacent teeth shift
  • Sharp edges causing soft-tissue injury to tongue and cheeks

Treatment Options

If you still have the crown, keep it safe and bring it to your appointment. Your dentist will assess whether:

  • The existing crown can be re-cemented — the quickest and most cost-effective solution
  • The underlying tooth needs treatment before re-fitting (e.g. decay removal)
  • A new crown is required — necessary when the old crown is cracked, worn, or ill-fitting
Key Differences

How Do Lost Fillings and Lost Crowns Differ?

Level of Tooth Protection

A filling restores part of a tooth, while a crown encases the entire visible structure. Losing a crown leaves significantly more tooth surface exposed and at risk.

Urgency and Sensitivity

Both situations can cause discomfort, but a lost crown is generally more urgent. The prepared tooth beneath a crown is often weakened or root-treated, making it more susceptible to fracture if left unprotected.

Treatment Complexity

Replacing a filling is usually a single, straightforward appointment. Crown treatment may involve re-cementation (simple) or fabrication of a new crown (two visits), depending on the condition of the original restoration.

Risk of Further Damage

A missing filling allows bacteria into the cavity, which can lead to deeper decay. A missing crown exposes a structurally compromised tooth that could fracture — sometimes irreparably.

Cost Considerations

Filling replacement is generally more affordable. Crown re-cementation is cost-effective, but a new crown is a larger investment. Seeking timely treatment may help avoid more complex and costly care later.

Pros & Cons

Weighing Up Your Treatment Options

Replacing a Lost Filling

Advantages

  • Quick, single-visit procedure in most cases
  • Lower cost compared to crown treatment
  • Preserves natural tooth structure
  • Tooth-coloured composites can blend naturally with surrounding teeth

Considerations

  • Fillings have a limited lifespan and may need replacing again
  • Not suitable for very large cavities or structurally weakened teeth
  • Some fillings may discolour over time

Reattaching or Replacing a Crown

Advantages

  • Provides full coverage and protection for weakened teeth
  • Re-cementation is quick and affordable when the crown is intact
  • Modern crowns are highly durable and natural-looking
  • Protects root-treated teeth from fracture

Considerations

  • New crown fabrication requires two appointments
  • Higher cost if a new crown is needed
  • Underlying tooth may need additional treatment before re-fitting
Pricing

Cost Comparison (UK Private)

Treatment
Indicative Cost*
Emergency examination
From £30
Composite filling (direct)
From £92.50
Crown re-cementation
From £75
New porcelain crown
From £495
Inlay / onlay
From £395

*Prices are indicative and may vary following clinical assessment. View our full fee guide for a detailed breakdown.

Decision Guide

Which Option Is Best for You?

Every case is different. Use the guidance below as a starting point — your dentist will confirm the most appropriate treatment after examination.

Best for Minor Tooth Damage

If a small filling has come out and the tooth is not heavily broken down, a replacement composite filling is usually the simplest and most cost-effective solution.

Best for Protecting Heavily Restored Teeth

If you have lost a crown — particularly from a root-treated or structurally weakened tooth — re-cementation or a new crown offers the most reliable long-term protection.

Best for Urgent Pain Relief

Significant sensitivity or throbbing pain warrants same-day attention. An emergency examination can determine whether the nerve is at risk and provide immediate relief.

Best for Long-Term Durability

For larger restorations or teeth under heavy biting forces, a crown or onlay provides superior strength compared to a standard filling.

Frequently Asked Questions

A lost filling is not always an immediate emergency, but it should be assessed promptly — ideally within a few days. The exposed tooth is vulnerable to further decay and sensitivity. If you experience significant pain, swelling, or signs of infection, seek urgent care sooner. Your dentist will advise on the most appropriate treatment following a clinical examination.
Generally, yes. A crown protects a tooth that has already undergone significant treatment, such as a root canal. When a crown comes off, the underlying tooth stump is fragile and at greater risk of fracture or infection. We recommend being seen within 24–48 hours wherever possible.
You can eat soft foods on the opposite side of your mouth, but avoid anything hard, sticky, or very hot or cold near the affected tooth. Chewing on an exposed tooth stump or cavity increases the risk of fracture and contamination.
In many cases, yes — provided the crown is undamaged and the underlying tooth is healthy. Your dentist can clean both surfaces and re-cement the crown during a straightforward appointment. If the crown is cracked or the tooth has decayed, a new crown may be needed. Always bring the original crown to your appointment.
For a lost filling, aim to be seen within a few days. For a lost crown, ideally within 24–48 hours. If you have severe pain, visible swelling, or signs of infection, contact an emergency dentist the same day.
Pharmacy temporary filling kits can provide short-term relief by covering an exposed cavity and reducing sensitivity. They are a reasonable stop-gap, but they are not a substitute for professional treatment. The temporary material will not bond properly and can mask underlying problems, so book a dental appointment as soon as you can.

Lost a Filling or Crown?

Our experienced team can assess your tooth, explain your options, and provide prompt treatment — often on the same day. No referral needed.

Our emergency dentist in the City of London and South Kensington clinics welcome new patients — no registration required.