What Are Inlays and Onlays?
Unlike traditional fillings or full crowns, **inlays and onlays** are indirect restorations fabricated in a dental laboratory or using CAD/CAM technology. They are used to restore teeth that have a large amount of decay or damage but do not require a full crown. An **inlay** fits within the cusps (the chewing surfaces) of the tooth, similar to a traditional filling. An **onlay**, also known as a partial crown, is larger and covers one or more cusps.
The Clinical Procedure
The procedure for an inlay or onlay typically requires two appointments. During the first visit, the dentist will remove the decayed or damaged portion of the tooth. Unlike a full crown, only the affected area is removed, preserving a significant amount of the healthy tooth structure. A precise impression or digital scan of the prepared tooth is then taken. This impression is sent to a dental lab where the inlay or onlay is fabricated from a durable material like porcelain, composite resin, or gold. A temporary filling is placed to protect the tooth.
At the second appointment, the temporary filling is removed, and the dentist will carefully place the new inlay or onlay. The fit is checked to ensure it is perfect and then bonded permanently to the tooth using a strong dental adhesive. This process results in a restoration that is precisely fitted to the tooth, strengthening it and preventing further damage.
Key Benefits and Considerations
The primary advantage of inlays and onlays is their ability to **conserve natural tooth structure**. They provide a solution that is more durable and long-lasting than a traditional filling, yet less invasive than a full crown. Because they are fabricated in a lab, they are stronger and more precisely shaped than fillings, which are placed directly in the mouth. This precision leads to a better fit and can significantly extend the life of the restored tooth. Inlays and onlays are an excellent choice for patients who need more than a filling but want to avoid a full crown.