Crown, onlay or overlay: how much of a tooth needs coverage?
Prosthetic restoration is selected according to remaining tooth structure and functional demands.
On this page
What is the difference?
A crown covers the prepared coronal portion of a tooth circumferentially. An onlay covers one or more cusps; an overlay covers the occlusal surface including all cusps. These terms describe different extents of restoration, rather than a particular material or bonding method.
Why not choose a crown straight away?
The decision considers the amount and distribution of healthy tissue, the defect, isolation and occlusal contacts. A partial restoration may conserve tissue when indicated. A crown may be justified in other circumstances; the smallest restoration is not automatically appropriate.
Does root canal treatment change the plan?
Yes, but assessment of remaining tissue is still essential. Definitive restoration and tooth protection belong to complete care. A post retains a core when needed; it does not universally strengthen the root. [1]
What should you understand beforehand?
Ask which parts are damaged and which can be retained. Discuss why the proposed coverage was selected and what maintenance it involves. A large filling does not create an identical treatment indication for every tooth.
Clinical sources
Further reading
- Torabinejad M, Fouad AF, Shabahang S. Endodontics: Principles and Practice. 6th ed. Elsevier, 2021.
- Shillingburg HT Jr et al. Fundamentals of Fixed Prosthodontics. 4th ed. Quintessence, 2012.
- Rosenstiel SF, Land MF, Walter R. Contemporary Fixed Prosthodontics. 6th ed. Elsevier, 2023.
Selected editions published from 2012 onwards. Books are recommended for further reading; clinical explanations reference the accessible sources above.
The information on this page is general and educational. It does not replace a medical consultation, and a treatment recommendation can only be made after examining each patient. Results differ from one case to another.
A plan for your situation
Book a consultationStart with a consultation and a plan
Every treatment begins with a diagnosis: clinical examination, photographs, radiographs and, where relevant, an occlusal analysis. Only then do we discuss options.