Dentist Questions Onlays

How do dental onlays differ from crowns?

Instead of a crown, my dentist gave me an onlay over my tooth. I didn't ask him what's the difference because I trust his judgement, but I never heard of an onlay before. How do they differ from crowns?

10 Answers

Onlays are "partial" crowns where one or two surfaces of your own tooth are strong enough and almost intact. Your dentist made the correct call by preserving intact areas of your tooth and replacing only weak or decayed areas.
An inlay conserves more tooth structure as compared to a crown. An onlay covers the cusps of a tooth, and is usually less costly than a full crown. A dental onlay can be thought of like a mini-crown.
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Inlays or inlays are a more conservative type restoration which frequently made of the exact same material as a crown. Crowns cover the entire tooth whereas an inlay is small enough to be completely surrounded by tooth structure. An onlay also includes one or more sides of the tooth.
Crowns you need to take more tooth structure and covers the tooth more. And it depends on the state of the tooth.
An Onlay is considered a more conservative approach to fixing a tooth when the options of restoring a tooth are limited to a crown. A crown covers the whole tooth and therefore the entire tooth has to be shaved or drilled on to reduce tooth structure the thickness of what the crown will be once cemented on the tooth. An onlay can be made to only replace the part of the tooth that is missing or damaged and therefore requires a lot less invasive treatment.
Onlays are becoming more popular due to new dental ceramic materials like Zirconia. They are highly aesthetic so now there is no need to prep the whole tooth to hide gray margins. Onlays are more conservative in regards of tooth structure. Less grinding. So they only cover the affected area instead of prepping the entire tooth for a crown that covers All of it.
Having an inlay preserves more of your actual tooth structure. Sometimes insurance companies will not pay for a crown if not enough tooth structure is damaged. Onlays work well.

Dana Truesdale, DDS
A crown vs onlay. A crown is full coverage of the tooth tip to gums. A large portion of the top and sides of the tooth are removed. Usually used when a large portion of the tooth is fractured, decayed or destroyed or when a root canal has been performed. An onlay is a more conservative way to replace some or all of the top portion of a tooth when a filling is not appropriate. It does not replace all surfaces of the tooth. It is a great way to keep the tooth without cutting large portions of it way and just replacing the portion that is affected.

Dr Jensen
Onlays differ from dental crowns in that they are much more conservative and save healthy tooth structure. You still get the benifit of chapel coverage while keeping as much tooth as possible.
Onlays do not cover the entire tooth. They are a conservative way to protect a tooth against fracture.