These sit in the gap between a filling and a crown, and they exist for a specific reason: some teeth need more than a filling can give but do not need to lose the amount of structure a full crown requires.
What usually brings this up
Restorative work repairs what damage, decay or wear has already done. The right treatment depends far more on how much sound tooth remains than on which procedure you have heard of.
- A cavity too large for a straightforward filling
- A cracked cusp that needs covering
- Replacing a very large old filling
- Wanting to preserve more tooth than a crown would
- A tooth under heavy biting forces
Treatment paths a dentist may weigh
There is nearly always more than one defensible option, including doing less. A good discussion covers the alternatives and what changes if you wait.
- Composite or ceramic inlay
- Onlay covering one or more cusps
- A conventional filling where the cavity allows
- A full crown where too little tooth remains
- Monitoring rather than treating, where the tooth is stable
Filling, inlay/onlay and crown compared
| Factor | Filling | Inlay or onlay | Crown |
|---|---|---|---|
| Tooth removed | Least | Moderate | Most |
| Made where | In the mouth | Laboratory or milled | Laboratory or milled |
| Visits | One | One or two | One or two |
| Best for | Small to moderate cavities | Large cavities with sound walls | Little sound tooth remaining |
| Covers cusps | No | Onlay does | Yes, entirely |
| Cost | Lowest | Middle | Highest |
How the treatment is planned
An examination and X-rays establish what can be kept and what cannot. From there the dentist should explain the recommended approach, the reasonable alternatives, the number of visits, and what could change once treatment begins.
Ask for the estimate in writing and ask what is excluded from it. Build-ups, root canals and laboratory work are the items most often priced separately — see dental insurance and financing.
Start with an assessment
Choose the restorative option that is closest when you request an appointment. We follow up to confirm the visit type and arrange care with a Vermont dental practice.
Common questions
What people ask before scheduling
Why not just have a big filling?
Very large direct fillings flex and can split the remaining tooth. An inlay or onlay is made outside the mouth and bonded in, which is more stable across a wide span.
Why not just have a crown?
A crown removes considerably more sound tooth. If the walls of your tooth are still strong, an onlay preserves them — that structure cannot be put back later.
What materials are used?
Commonly ceramic or composite. The choice depends on the bite forces, the size of the restoration and appearance requirements.
Do they last as long as crowns?
Well-made bonded restorations perform well, and the more conservative preparation is the point. Longevity depends on the bite, the bond and cleaning, as with any restoration.
Can I be told which treatment I need before an examination?
No. Restorative options depend on how much sound tooth remains, which requires examination and X-rays. Anyone offering a treatment plan sight unseen is guessing.
Will I get a price before treatment starts?
You should get a written, itemized estimate after the assessment. Ask specifically what is excluded — build-ups, root canals and laboratory work are commonly quoted separately.
What happens if I wait?
That is a fair question to ask directly, and a good dentist will answer it plainly. Some situations are stable for a while; others get more expensive the longer they are left.
Patient education sources
Sources were checked on August 19, 2026. Personal recommendations require a dental examination.