Crowns vs. Onlays: What's the Difference?

Crowns and onlays are both common dental restorations used to repair damaged or decayed teeth, but they serve different purposes and are used in different situations. A crown is a "cap" that covers the entire tooth, restoring its shape, size, and strength. Crowns are typically recommended when a tooth is severely damaged or weakened, for instance, after a root canal treatment, or when a large portion of the tooth is lost to decay. They provide full coverage and protection, ensuring the tooth can function normally and is protected from further damage.

Onlays, on the other hand, are more conservative than crowns and are used when the damage to the tooth is not extensive enough to require a full crown. An onlay covers one or more cusps (the raised points on the tooth) and part of the chewing surface but does not extend to cover the entire tooth. Onlays are often referred to as partial crowns because they offer a middle ground between a filling and a full crown. They are particularly useful when the tooth structure is still strong and healthy, allowing for the preservation of more of the natural tooth.

When choosing between a crown and an onlay, several factors need to be considered, including the extent of the tooth damage, the location of the tooth, and the patient's budget. Crowns are generally more durable and provide comprehensive protection, but they require more removal of the natural tooth structure. Onlays, while less invasive, may not be suitable for teeth that are extensively damaged or have undergone root canal treatment. Additionally, the materials used for both crowns and onlays can vary, including porcelain, ceramic, or metal, each offering different benefits in terms of strength, durability, and aesthetics.