What Are Inlays and Onlays?

Inlays and onlays are custom-made restorations used to repair damaged or decayed teeth. They can be crafted from porcelain, gold, or composite resin and are securely bonded to the affected area of the tooth.

An inlay is similar to a filling and is placed within the grooves (cusp tips) of the tooth. An onlay is a larger restoration that covers one or more cusps, providing additional strength and protection to the tooth.

Traditionally, gold was the most commonly used material for inlays and onlays due to its durability. Today, porcelain has become a popular choice because of its strength and natural appearance, allowing it to closely match the colour of your surrounding teeth.

How Are Inlays and Onlays Applied?

Inlays and onlays are usually completed over two dental appointments.

During the first visit, the dentist removes any old filling, decay, or damaged tooth structure and carefully prepares the tooth. An impression is then taken to ensure the inlay or onlay fits accurately and aligns properly with your bite. This impression is sent to a dental laboratory where your custom restoration is made. A temporary seal is placed on the tooth to protect it until your next appointment.

At the second visit, the temporary seal is removed and the dentist checks the fit and bite of the inlay or onlay. Once the fit is confirmed, the restoration is securely bonded to the tooth using a strong resin and polished to create a smooth, natural finish.

Considerations for Inlays and Onlays

Traditional fillings can reduce the strength of a natural tooth by up to 50%. In contrast, inlays and onlays are bonded directly to the tooth using advanced, high-strength resins, which can increase the tooth’s strength by up to 75%.

Because of their durability and strength, inlays and onlays can last between 10 and 30 years with proper care. When a tooth is damaged but does not require a full crown, an onlay can be an excellent, more conservative alternative.

FAQS

Q: What are inlays and onlays?
A. Inlays and onlays are custom restorations used to repair damaged teeth. Inlays fit within the tooth, while onlays cover one or more cusps for added strength.

Q: What are they made from?
A: They can be made from porcelain, gold, or composite resin. Porcelain is popular because it looks natural and is very durable.

Q: How many visits are needed?
A: Usually two appointments, one to prepare the tooth and take an impression, and another to bond the inlay or onlay in place.

Q: Are they better than fillings?
A: In many cases, yes. Inlays and onlays can strengthen the tooth and last longer than traditional fillings.

Q: How long do they last?
A: With proper care, they can last 10–30 years.

Q: Do I need a crown instead?
A: An onlay may be recommended if the tooth needs more coverage than a filling but doesn’t require a full crown.