Per tooth for selected local defects.
Restoration comparison
Use enough coverage, but no more than the tooth needs.
A filling replaces a local defect. An onlay covers selected cusps. A crown surrounds most of the visible tooth. The choice depends on remaining structure, cracks, decay, bite force, and previous treatment.
Coverage and laboratory requirements vary.
Per crown when broader coverage is indicated.
The most conservative option is the least invasive restoration that can manage the diagnosed damage and biting forces. That is not always the smallest or the cheapest restoration.
Side by side
Three levels of coverage.
Longevity figures are broad ranges, not guarantees. A smaller restoration on the wrong tooth can fail early, while unnecessary full coverage removes sound structure that cannot be replaced.
| Compare | Filling | Onlay or inlay | Crown |
|---|---|---|---|
| Often considered for | Small to moderate local decay or damage with supported tooth structure | Moderate damage where selected cusps need coverage | Extensive structural loss, cracks, or selected root-treated teeth |
| Coverage | Replaces the local defect | Replaces the defect and covers selected areas or cusps | Covers most of the visible tooth |
| Tooth preparation | Local preparation | More than a filling, less than many crowns | Substantial preparation around the tooth |
| Starting price | From $200 per tooth | Quoted after assessment | From $1,600 per crown |
| Appointments | Often one visit | One or more visits depending on fabrication | One or more visits depending on fabrication |
| Indicative longevity | Often 5 to 10 years, but varies | Often 10 to 15 years, but varies | Often 15 years or longer, but varies |
| Main tradeoff | Preserves more tooth but may not support weakened cusps | Balances preservation with selected coverage | Provides broad coverage but removes more tooth |
How the choice is made
Remaining structure matters more than the hole size.
Walls and cusps
Thickness, cracks, undermining, existing fillings, and how much supported tooth remains affect whether local repair is enough.
Location and bite
Molars, premolars, front teeth, bite contacts, grinding, and clenching place different forces on a restoration.
Decay and cracks
Depth, spread, symptoms, crack direction, and whether the nerve is involved can change the plan or require staged treatment.
Previous root canal
Structural loss and tooth position determine whether cuspal coverage is indicated after root canal treatment.
Illustrative scenarios
The same symptom can lead to different coverage.
Often discuss a filling
A small cavity with strong surrounding tooth
Local repair can preserve the most tooth when the walls and cusps remain supported and no wider crack is present.
An onlay may enter the discussion
A weakened cusp beside a large old filling
Selected cuspal coverage may distribute force while preserving more tooth than full coverage, if the crack and margins allow it.
A crown may enter the discussion
Extensive damage or a structurally weak back tooth
Broader coverage can support remaining structure, but nerve health, restorability, bite, and alternatives still need assessment.
Limits and risks
Every restoration exchanges tooth structure for support.
Filling
- Can fracture, wear, leak, or develop decay at the margin.
- A large filling may not protect weakened cusps.
- Repeated replacement can remove more tooth over time.
Onlay
- Requires irreversible preparation.
- May chip, debond, or need replacement.
- Cannot protect cracks or damage beyond its planned coverage.
Crown
- Requires substantial irreversible preparation.
- Temporary sensitivity or future nerve treatment can be needed.
- Can chip, loosen, develop margin decay, or require replacement.
Before treatment
Five questions about the tooth.
- 01
How much supported tooth remains?
Ask which walls or cusps are weak and what the recommended restoration is protecting.
- 02
Is there a crack, and how far does it extend?
Symptoms and imaging can suggest a crack, but its full extent is not always visible before treatment.
- 03
What happens if we choose the smaller restoration?
Understand the risk of fracture, repeated repair, or needing broader coverage later.
- 04
What sound tooth must be removed for the larger restoration?
Onlays and crowns are irreversible, so the structural benefit should justify the preparation.
- 05
Is monitoring a reasonable option?
Selected stable findings may be monitored when symptoms, decay, cracks, and structural risk allow it.
If the tooth is not restorable
Coverage is not always the endpoint.
Nerve care, extraction, or referral
Deep decay, a crack below the gum or into the root, infection, or insufficient remaining tooth can make a filling, onlay, or crown unsuitable.
The next discussion may include root canal treatment, crown lengthening, extraction, replacement options, specialist review, or monitoring. Assessment should happen before a restoration is sold as inevitable.
Related decisions
Read around the restoration.
Common questions
Coverage decisions, without a fixed threshold.
Why might a tooth need a crown if it does not hurt?
Pain is not the only sign of structural risk. Cracks, a large existing restoration, weakened cusps, wear, decay, or previous root canal treatment can affect how much force the remaining tooth can tolerate. The recommendation should be based on examination and imaging, not symptoms alone.
Can a filling be replaced with a crown later?
Yes, when the remaining tooth and diagnosis support it. Repeated filling replacement can remove more tooth over time, but placing a crown early also requires substantial preparation. The decision balances current damage against the cost of removing additional sound structure.
Is an onlay more conservative than a crown?
Often, because an onlay covers selected damaged cusps rather than the whole visible tooth. It is not suitable when cracks, decay, existing restorations, or the pattern of remaining structure require broader coverage.
Does every root canal tooth need a crown?
No single rule fits every tooth. Back teeth often need cuspal coverage after root canal treatment because of existing structural loss and biting forces. Front teeth and selected well-supported teeth may be managed differently after assessment.
Can a large filling make a tooth crack?
A large restoration can leave thinner cusps and walls that flex or fracture under load. Bite force, grinding, decay, material, and the remaining tooth all affect risk. An onlay or crown may be discussed when a filling cannot provide predictable support.
How long do fillings and crowns last?
Composite fillings often remain serviceable for about 5 to 10 years and crowns often for 15 years or longer, but there is wide variation. Size, position, bite, grinding, decay risk, margin care, trauma, and material influence longevity.
A considered first step
Protect the tooth with the least coverage that is likely to hold.
We can assess the remaining structure, cracks, nerve health, bite, and alternatives before explaining whether a filling, onlay, crown, or another path is appropriate.