General — 5 min read
Inlay, Onlay
The restoration between a filling and a crown — and often the one you should have been offered before the crown was proposed.
Screened and introduced free, usually within a few hours. Sunny Isles Beach, Florida and the surrounding corridor.
Indications
An inlay or onlay is often the better option when
An inlay sits within the cusps of a tooth; an onlay extends over one or more cusps to protect them. Both are made outside the mouth in ceramic or gold, then bonded in — preserving the tooth structure that a full crown would remove.
- A cavity or old filling is too large for direct composite but the walls are sound
- A cusp is cracked and needs covering, but the rest of the tooth is intact
- An old amalgam filling is leaking and the tooth around it is otherwise strong
- You have been offered a crown and want to know whether less would do
- A root-canal-treated tooth needs cuspal protection with good remaining walls
- You want a restoration that bonds to the tooth rather than merely capping it
Good candidate if
- The surrounding walls of the tooth are intact
- The damage is too extensive for a direct filling
- You want to preserve tooth structure for the future
- The practice can isolate properly with a rubber dam
No cost, no obligation, no lead list.
The detail
Why preserving the walls matters
The restoration between a filling and a crown — and often the one you should have been offered before the crown was proposed.
A crown preparation removes one to two millimetres from every surface, which on a molar is a substantial proportion of the remaining tooth. An onlay removes only the damaged part and covers the vulnerable cusps. Because modern ceramics are adhesively bonded rather than merely cemented, the restoration and the tooth function as one structure, and laboratory studies consistently show bonded onlays restoring fracture resistance close to that of an intact tooth.
The practical argument is about what happens next. Teeth get restored, then re-restored, and each cycle removes more structure — filling, then onlay, then crown, then root canal, then extraction. Choosing an onlay rather than a crown now keeps a step in reserve. It matters most on younger patients and on teeth likely to need work again in twenty years, which is most of them.
The sequence
What actually happens, in order.
Timings vary between practices and cases. The order does not — and a plan that skips a step is worth asking about.
Assess the walls
How much sound structure remains, and whether cusps are cracked or undermined. This decides inlay, onlay or crown.
Preparation
Decay and the old filling removed, cavity shaped for a bonded restoration. Far more conservative than a crown prep.
Scan and temporary
A digital scan, then a temporary restoration — or milled chairside in a single visit where available.
Fabrication
Milled or pressed in lithium disilicate, or cast in gold where longevity outweighs appearance.
Adhesive bonding
Bonded under rubber dam isolation. This step is technique-sensitive and the isolation is what makes it last.
Getting the right hands
Who should be doing your inlay, onlay.
This is the variable that decides your result, and it is the one you have least ability to assess from the outside.
Not years in dentistry. How many of these they do in a month, and what the difficult ones looked like.
Anyone can photograph a result on delivery day. We want to see it after it has been used.
CBCT, microscope, scanner, printer — whichever this case genuinely requires, on site rather than referred out.
For anything ceramic, the technician is half the result. A dentist who cannot name theirs is outsourcing blind.
Inlay, Onlay FAQ
What people ask us about inlay, onlay.
Including the cost question, answered with a real range rather than a request to call.
An inlay sits inside the cusps, an onlay covers one or more cusps, and a crown covers the entire tooth. They form a ladder of increasing coverage and increasing tooth removal. The correct answer is the least coverage that protects what is actually weak.
Typically $1,000 to $2,000 in South Florida, broadly comparable to a crown. It is generally not cheaper — the benefit is biological rather than financial. Insurance usually covers onlays at a similar rate to crowns.
For a tooth with intact walls, a bonded ceramic onlay restores fracture resistance to close to that of a natural tooth, and it does so while keeping more of that tooth. Where walls are already missing or the tooth is severely cracked, a crown is the correct choice.
Sometimes correctly, when the walls are genuinely compromised. Sometimes because crowns are more forgiving of technique and do not require rubber dam isolation and adhesive protocol. It is reasonable to ask directly whether an onlay would suffice and why not, if not.
Ten to twenty years for well-bonded ceramic. Gold onlays regularly exceed twenty-five and remain the most durable option in dentistry, which is why some dentists still choose them for their own back teeth.