Onlay
Definition
A custom restoration that covers one or more cusps of a tooth. Onlays extend over the biting surface, providing more coverage than inlays while being more conservative than full crowns. Also called 'partial crowns.'
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Related Terms
Inlay
A custom restoration that fits within the cusps of a tooth, larger than a filling but smaller than a crown. Inlays are used when decay or damage is too extensive for a filling but doesn't require full crown coverage. Made from ceramic, gold, or composite.
Cusp
The pointed or rounded projection on the chewing surface of a tooth. Molars typically have 4-5 cusps; premolars have 2. When cusps are damaged or worn, a crown may be needed. Onlays cover one or more cusps while preserving healthy tooth structure.
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Medically reviewed by Dr. Morad Masour Rad, DDS · Last reviewed
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