Inlays & Onlays

Inlays and Onlays

At your next dental appointment, you may find that your dentist suggests that you undergo an inlay or an onlay. It’s important to understand what these procedures include before agreeing to move forward with the procedure.

Traditional inlays were used instead of fillings to replace a small amount of tooth loss that was due to decay. Onlays are similar, but instead of just fitting inside of the tooth, they also cover the chewing surface. Onlays are typically used on the back teeth and will cover one or more of the cusps of the tooth.


Inlays were initially made of gold and looked like fillings. Today, medical advances have allowed for inlays to be made of substances that more closely mirror the appearance and function of the tooth. Inlays may be made of ceramic, porcelain or a type of dental composite.

If you’ve had previous fillings that are failing or that appear unsightly, your dentist can replace or repair them with a modern inlay. This will improve the function and appearance of the filling.


Onlays also fit inside of the tooth but also cover one or more cusp of the chewing surface. These types of fillings are typically used on the molar teeth. Like inlays, onlays were previously made of the same material as fillings, gold.

New developments have allowed for ceramic or porcelain onlays that more closely match the original tooth color. These material types also allow for bonding of the material to the tooth. Recent research suggests that these onlays and their bonds strengthen and improve the tooth.

Knowing When to Use Inlays or Onlays

It’s tough for a patient to understand all the details that make an inlay or onlay the best option to use. While your dentist will typically consider their use, you may also raise the question about them if your dentist is considering a crown or cap. All these treatments have specific benefits and drawbacks, so you should make sure to clarify any questions with your dentist before agreeing to a particular treatment.

The Process

Inlays and onlays are like crowns. However, they require less removal or altering of your existing tooth structure. For this reason, they may be preferred for many patients over a crown.

Once the tooth has been adequately prepared, and all the tooth decay and debris have been removed, an impression of the tooth is made. This impression can be made digitally or with a putty like material that will create a physical cast of your tooth.

This impression is then sent to a laboratory where they create a model of your tooth. The final restoration is created in the lab and is designed to perfectly fit your tooth. If you have opted for a color-treated inlay, it should also match your existing tooth color.

At your initial visit, you won’t leave with the permanent onlay because it hasn’t been created at the laboratory yet. Instead, your dentist will give you a temporary filling to protect your tooth while you wait.

At your second appointment, your dentist will install your inlay or onlay. They may have to shape it slightly to fit your tooth, but this is usually minimal. After the restoration fits your tooth, your dentist will permanently attach it to your tooth with a resin, or type of glue, that cures when it is exposed to a specific kind of light.

After the tooth is cured, it should be as strong or stronger than your other teeth and requires the same level of care.


If your dentist has suggested that you receive a cap or crown, you may also want to inquire about the possibility of inlays or onlays. These treatments require less tooth removal in order to be installed and may improve the strength and integrity of your tooth. If you have further questions or concerns, please contact your dentist today.