Assessment of crown and core
We examine the inside of the crown for decayed tooth or broken fragments, check the remaining core for softness and cracks, and take an X-ray to see the root and any existing root filling.
About this treatmentDental condition · Wimpole Street, Marylebone
Loose crown: what to do with it, and why the tooth underneath is the real question
A crown that rocks, lifts when you eat something sticky or comes away entirely is unsettling but rarely dangerous. What matters is less the crown than the tooth it was covering. A crown sits on a prepared core of natural tooth held by a thin layer of cement, and when it loosens something has changed in that arrangement: the cement has washed out, the core has decayed or fractured, or the forces on it have been too great. The core is now exposed. It may be sensitive, it is soft compared with the crown that protected it, and it is vulnerable to further decay and to drifting of the neighbouring teeth if left uncovered for long. Many loose crowns can simply be cleaned and re-cemented; some reveal a problem that needs treating first; a few cannot be saved. Our Wimpole Street dentists check the crown, the core and the X-ray before deciding which of those you are dealing with.
Recognising it
How it usually feels
A crown that moves when you push it with your tongue
The cement seal has failed on at least part of the tooth.
A sudden gap or a hollow feeling after chewing something sticky
Toffee, chewing gum and dried fruit are the usual culprits for lifting a crown that was already loose.
A sour or metallic taste around the tooth
Bacteria and fluid seeping under a leaking crown.
Sensitivity to cold or sweet on one tooth
The exposed core reacting; the nerve is still alive.
The crown has come off with a chunk of tooth inside it
The core has fractured; re-cementing may not be possible.
Behind the symptoms
What's going on
- 01
Cement fatigue
Every cement degrades slowly in the wet, warm, acidic environment of the mouth. After ten or fifteen years of chewing, the bond weakens, fluid gets underneath and the crown eventually lifts. This is the benign explanation, and a re-cement is usually all that is needed.
- 02
Decay under the margin
Where the crown edge meets the tooth is the weak point. Plaque left there dissolves the tooth beneath the crown, softening the core until the crown no longer has anything sound to grip. The crown often looks fine from outside.
- 03
A short or tapered core
Crowns rely on the height and shape of the underlying tooth for retention. A tooth that was heavily broken down before it was crowned, or that was prepared with too much taper, has little to hold on to and loosens more readily.
- 04
Heavy bite forces
Clenching and grinding, or a crown that meets the opposing tooth slightly before the others, subject the cement to constant flexing. Root-treated teeth with a post can also loosen at the post rather than at the crown.
- 05
Fracture of the tooth
A root-treated tooth is dry and brittle. If it cracks at gum level, the crown comes off with the broken portion inside it and the remaining root may be too short to rebuild.
Before your appointment
What you can do today
- If the crown has come off, rinse it, keep it dry in a small container and bring it with you; do not throw it away even if it looks damaged.
- Keep the exposed tooth clean with a soft brush and avoid chewing on that side; very hot, cold or sweet foods may cause twinges.
- If the tooth is sensitive and you must wait a day or two, a pharmacy temporary dental cement can hold the crown in place briefly; never use superglue or household adhesives.
- Do not force the crown back on if it does not seat easily or feels high; you may be trapping debris or cracking the core.
These are holding measures, not a substitute for an examination. Use any pain relief exactly as directed on the pack and check with a pharmacist if you take other medicines.
In the chair
How we treat it at Wimpole Street
Re-cementation
When the crown is intact and the core is sound, both are cleaned and dried and the crown is re-bonded with fresh cement. Fifteen to thirty minutes, and often done at the first visit.
About this treatmentRebuilding the core first
Where decay has softened the tooth, it is removed and the core is rebuilt in composite before the old crown is refitted or a new one made. If the nerve has been affected, root canal treatment comes first.
About this treatmentA new crown
If the old crown is damaged, no longer fits the rebuilt tooth or has an open margin, a new one is made from a digital scan and fitted about two weeks later, with a temporary in between.
About this treatmentExtraction and replacement
A root fractured below the gum or too short to restore is removed, and an implant, bridge or denture is planned once the site has healed.
About this treatmentFees
Costs to expect
An emergency appointment at Wimpole Street to assess a loose or lost crown, including X-ray and re-cementation where the crown and tooth are sound, is expected to be around £95. Rebuilding a decayed core in composite is from £185 before the crown is refitted.
A replacement crown is indicative from £995, and root canal treatment where the nerve is involved is around £695 for a front tooth or £895 for a molar. Extraction of an unsaveable root is from £250, with an implant and crown from £2,950 or a bridge from £995 per unit if you choose to replace it. Every route, with its fee and likely lifespan, is set out in writing before you decide.
Figures are indicative prices for Wimpole Street and are confirmed in a written plan once a dentist has examined you. Fees match our South Kensington and St Paul's clinics.
Don't wait if
When to see a dentist
- A crown moves, however slightly, when you press it.
- A crown has come off, with or without tooth inside it.
- A crowned tooth has become sensitive to temperature or sweet.
FAQ
Common questions
A few days is usually fine, though it may be sensitive. Beyond a couple of weeks the neighbouring and opposing teeth start to drift into the space, which can mean the old crown no longer fits, and the exposed core is at increasing risk of decay and fracture. Sooner is simpler and cheaper.
Often, if it is undamaged, the tooth inside is sound and it still seats fully. If decay has changed the shape of the core, if tooth has fractured away inside the crown or if the margin no longer fits, a new crown is needed. We can usually tell you within a few minutes of looking.
Either there is old cement, food or a fragment of tooth inside it preventing it from seating fully, or the neighbouring teeth have moved slightly since it came off. Do not bite down to force it; a high crown can crack the core. We clean everything out and check the fit before cementing.
Not necessarily. A root-treated tooth has no nerve and will not feel anything however much it decays, and even a live tooth can be surprisingly quiet under a leaking crown. Lack of pain is not a reason to delay having it looked at.
Keep the margin clean with floss or interdental brushes, avoid using crowned teeth on very hard or sticky foods, and wear a night guard if you clench or grind. Have crowns checked at each examination so that early leakage is caught before the core is damaged.
Marylebone, W1
Wimpole Street opens 1 October 2026
Leave your details and we will be in touch when the Marylebone diary opens. If the problem cannot wait, the same clinicians are already seeing patients in South Kensington and at St Paul's.
Related conditions
Opening 1 October 2026
Wimpole Street is not yet seeing patients. Until then, please book or call our South Kensington clinic on 020 7183 2362 or our St Paul's clinic on 020 7183 3709. Questions about the new clinic: wimpolestreet@md.co.uk.
Until we open
Need an appointment before 1 October 2026?
The same clinical team already works from two other Medical & Dental clinics. Book at either one now and, if you prefer, move your ongoing care to Wimpole Street once the doors open.
South Kensington
- 20 Old Brompton Road, London SW7 3DL
- Open seven days a week
- 020 7183 2362
St Paul's, City of London
- 5 Ave Maria Lane, London EC4M 7AQ
- Open Monday to Friday
- 020 7183 3709
