In brief
A dental crown covers and strengthens an entire tooth, while a filling repairs a smaller area of damage. The appropriate option depends on how much healthy tooth structure remains, the location of the damage and the condition of the tooth. Fillings suit small to moderate cavities where the tooth's walls are still sound; crowns are used when so much structure is missing or weakened that a filling would leave the tooth vulnerable to fracture.
Key takeaways
- Fillings repair a localized area; crowns cover the whole tooth above the gum.
- The deciding factor is how much sound tooth structure remains.
- Fillings are usually completed in one visit; crowns typically take more.
- Large fillings that keep breaking may signal that a crown is needed.
How fillings work
A dental filling repairs damage from decay or small fractures. The dentist removes the decayed portion and fills the space, most often with tooth-coloured composite bonded directly to the tooth. Fillings preserve the maximum amount of natural tooth and are usually completed in a single visit. They perform well when surrounded by enough healthy enamel and dentin to support them.
The limitation is structural. A filling replaces missing tooth material but does not reinforce the remaining walls. As fillings grow larger, the surrounding tooth walls grow thinner and more prone to cracking under chewing forces.
How crowns work
A crown is a custom-made cap that covers the entire visible tooth. The tooth is shaped, an impression or digital scan is taken, and the crown — commonly porcelain, ceramic or metal-based — is fabricated and cemented in place. Because it wraps the whole tooth, a crown distributes biting forces evenly and holds weakened structure together rather than wedging it apart.
Crowns typically require at least two visits when lab-made, with a temporary crown worn in between. They are the standard recommendation after significant structural loss and are frequently placed after root canal treatment on back teeth, as explained in why is a crown often recommended after root canal treatment.
How dentists choose between them
The core question is structural: after the decay or damaged material is removed, what remains? Considerations include:
- Extent of damage. Decay involving multiple surfaces or a cusp of a back tooth pushes toward a crown.
- Existing restorations. A tooth that is already more filling than tooth is a weak candidate for yet another, larger filling.
- Cracks. Visible crack lines or crack symptoms favour full coverage, which holds the tooth together.
- Bite forces. Heavy grinders and clenchers place extra demand on compromised teeth.
- History. A filling that has broken or fallen out repeatedly is telling you something.
Warning signs that a tooth has crossed the line are described in signs a tooth may need a dental crown. When damage reaches the nerve, the conversation changes again — see how that decision works in do you need a root canal or a dental filling.
Cost and longevity perspective
Fillings cost less and are quicker, and for appropriate cavities they are the right choice — a crown on a small cavity would be overtreatment. Crowns cost more upfront but protect heavily damaged teeth against fractures that could otherwise lead to root canals or extraction. Both restorations last many years with good care, though individual results vary; longevity questions are covered in how long do dental crowns last.
When to contact a dentist
If you have a broken filling, a cracked or heavily filled tooth, or sensitivity in a tooth with a large restoration, an examination will show whether repair or full coverage is the sounder path. Addressing borderline teeth before they fracture usually means simpler, more predictable treatment.
Frequently asked questions
Can a very large filling be placed instead of a crown?
Sometimes, but it involves trade-offs. A large filling in a structurally weak tooth carries a higher risk of the tooth fracturing later. Dentists weigh this risk against cost and other factors, and should explain the reasoning either way.
Does getting a crown hurt?
The procedure is done under local anaesthetic, and most patients find it comparable to a filling appointment. Mild sensitivity for a few days after each stage is common.
Is a crown permanent?
A crown is cemented in place and not removable by the patient, but like all restorations it can eventually wear or develop problems at the margins. Regular checkups monitor its condition.
What happens if I delay a recommended crown?
The risk is fracture. A cracked or heavily filled tooth can break in a way that makes it harder — or impossible — to save. Timeframes are unpredictable, which is why dentists prefer to protect vulnerable teeth before they break.
Sources
- Canadian Dental Association — Fillings
- Canadian Dental Association — Crowns
- Cleveland Clinic — Dental Crowns
This content is intended for general educational purposes and does not replace an examination, diagnosis or personalized treatment recommendation from a dental professional.