Fillings and crowns both repair damaged teeth, but they protect the tooth in different ways. A filling replaces a defined area of lost tooth structure. A crown covers and reinforces most or all of the visible tooth above the gum.
The choice is not simply about which treatment lasts longer or costs more. It depends on how much healthy tooth remains, where the damage is, the forces placed on the tooth and whether the nerve or existing restorations have been affected.
What is a dental filling?
A filling repairs a cavity, small fracture or worn area after damaged material has been removed. Tooth-coloured composite can be bonded directly to the tooth and shaped to restore function and appearance.
Dental fillings are usually most appropriate when enough healthy enamel and dentine remain to support the repair. A conservative filling preserves more natural tooth structure than a full-coverage restoration.
What is a dental crown?
A crown is a custom-made cap fitted over a prepared tooth. It can protect a tooth that is heavily filled, cracked, badly broken or weakened after root canal treatment. Crowns can be made from ceramic, metal or combinations of materials.
A dental crown requires more preparation than a filling because space is created around the tooth for the restoration. This is justified when broader coverage is needed to hold the remaining structure together.
How does a dentist choose between them?
- Size and depth of decay or fracture.
- Amount and quality of tooth structure remaining.
- Presence of cracks or undermined cusps.
- Position of the tooth and chewing forces.
- Size and condition of existing fillings.
- Whether root canal treatment has been completed.
- Bite, grinding habits and history of previous breakage.
When is a filling usually enough?
A filling may be suitable when the damaged area is limited and the surrounding tooth is strong. Small to moderate cavities, minor chips and replacement of a failing filling can often be managed directly.
Making a filling too large can leave thin walls or cusps that flex and fracture. Your dentist considers not only whether the space can be filled, but whether the repaired tooth will cope with normal use.
When might a crown be recommended?
A crown may be recommended when a substantial part of the tooth is missing, a crack threatens its integrity or a large old filling leaves the tooth weak. Back teeth that have had root canal treatment often need protective coverage, although the final decision depends on the tooth.
Crowns are not invulnerable. The tooth margin can still decay and the supporting gum must remain healthy. Daily cleaning and regular reviews remain essential.
Is an onlay a middle option?
Sometimes. An onlay is made outside the mouth and bonded to cover one or more weakened cusps without covering the entire tooth. It can provide more support than a direct filling while preserving more tissue than a crown.
Onlays are not suitable for every fracture or decay pattern. The preparation must allow secure bonding, adequate material thickness and a clean margin.
What happens during treatment?
For a filling, the tooth is usually numbed, the damaged area is cleaned, and the material is placed, shaped and polished in one visit. For a crown, the tooth is prepared and recorded with a scan or impression. A temporary crown may be worn while the final one is made, followed by a fitting visit.
Your dentist should explain expected sensitivity, how to clean the restoration and what to do if the bite feels uneven.
Which lasts longer?
Lifespan depends on size, material, tooth position, bite forces, diet, cleaning and maintenance. A crown may offer stronger coverage for a heavily compromised tooth, but a small well-maintained filling may be the better and more conservative treatment for limited damage.
The goal is not to choose the biggest restoration. It is to use the least invasive option that predictably protects the tooth.
Frequently asked questions
Can a large filling be replaced with another filling?
Sometimes, but the remaining tooth must be strong enough. A crown or onlay may be safer if the walls or cusps are weakened.
Does every root-filled tooth need a crown?
No single rule applies to every tooth. Back teeth often need cuspal coverage, but your dentist will assess the remaining structure and forces.
Is a crown painful?
The tooth is normally numbed during preparation. Mild temporary sensitivity can occur, and you should contact the practice if discomfort persists.
Can a crown get decay underneath it?
Decay can develop at the edge if plaque is not controlled. Careful cleaning and regular checks help protect the supporting tooth.
Repair the tooth with the right level of support
Book an assessment at Montagu Dental to compare a filling, onlay or crown based on the condition of your tooth and bite.
