Difference Between Inlays and Onlays

When a patient has tooth decay or cavities, fillings and crowns tend to be the most popular solution. Fillings are used for smaller cavities, while crowns help conceal substantial tooth decay. Sometimes, however, neither option is satisfactory €” for example, if you have a moderate amount of decay, fillings might be too miniscule, while crowns may be too large. In these cases, dental inlays and onlays are preferred. Let’s go over what inlays and onlays are, the differences between them and the unique benefits they bring.


Dental inlays and onlays are customized restorations used for decaying molars or premolars. They’re typically made with one of the following materials:

  • Porcelain
  • Ceramics
  • Composite resins
  • Gold

In the past, gold was the most commonly used material. Nowadays, however, more and more patients opt for ceramics or composite resins, as they can be designed to match the precise shape and coloration of your teeth. Both inlays and onlays fit seamlessly into your mouth and replicate your bite force, resulting in a happy, healthy smile for years to come.


While both inlays and onlays help rectify cavities, they’re not interchangeable solutions. They differ in two key ways:

  • Their function
  • The area in which they’re applied

Inlays are commonly used on patients with cavities that are too large for fillings. Onlays, on the other hand, are used to fix cracks, fractures and decays that are too widespread for fillings, but not serious enough to justify a full crown installation. Inlays may be referred to as €œindirect fillings,€ while onlays are sometimes called €œpartial crowns.€

In addition to serving different purposes, inlays and onlays are applied to different areas of the tooth. Inlays are installed within the cusps (or the bumps on top of your teeth) and help minimize damage done to the surface of the tooth. In comparison, onlays are a more extensive solution. They can cover the entire cusps, as well as the biting surface of the tooth.


For many patients, inlays and onlays are a superior alternative to fillings and crowns. Here are a few key benefits that make them special.

Durable and Long Lasting

When made with high-quality materials, inlays and onlays are extremely durable. They provide additional strength and are more resistant to external damage. Not to mention, you can enjoy them for a long amount of time €” most inlays and onlays last anywhere from 15 to 30 years (which is longer than a standard filling).

Protects Against Bacteria

Patients with decay or tooth fractures are more vulnerable to harmful bacteria. When these bacteria enter a crack or fracture, it can cause an infection that harms your gums and teeth. Inlays and onlays are attached directly to the teeth, making it harder for the bacteria to inflict damage.

Improved Strength

Inlays and onlays don’t just conceal cracks and tooth structure loss €” they also fortify your teeth by improving your bite force. If your bite force is weak, your jaw won’t receive stimulation, which can lead to problems like headaches, sagging skin and facial structure changes.

More Customizable Than Fillings

Compared to fillings, inlays and onlays offer stronger customization options. Not only can they match the precise color of your teeth, but you can also choose between different materials. The result is a personalized solution that integrates smoothly in your mouth and lasts for several years.

Less Invasive Than Crown Installations

In a crown installation, the tooth is cut down and molded so that a dental crown can be placed on top of it (a process that’s both time-consuming and burdensome). With onlays, however, only a small portion of the tooth is removed. Ultimately, inlays and onlays retain more of the natural tooth structure and are quicker than crown installations.


Now that you know what inlays and onlays are, you might be wondering: how are they installed? First, the Dynamic Smile Design team will examine the tooth decay to determine the best solution. If they decide that inlays or onlays are right for you, they’ll schedule two appointments: one to remove the tooth decay, and another to install the inlays or onlays.

During the first appointment, Dr. Reshma J. Patel will carefully remove tooth decay and clean the affected area. If necessary, she’ll apply a local anesthetic to numb the area first. Then, she will take a dental impression of your tooth before covering it with a temporary restoration. This impression is sent to a technician who will create a custom inlay or onlay that matches your teeth.

After about a week or so, patients can come in for their second appointment. Dr. Patel will start by removing the temporary restoration €” then, she’ll attach the inlay or onlay to your teeth using cement. Once it’s secured in your mouth, she’ll modify it as needed to ensure it aligns with your bite. The end product is a minimally invasive, quality tooth cover that looks and feels like natural teeth.


Dealing with tooth decay is no laughing matter. When left untreated, cavities can escalate and lead to more complex issues, such as infections, periodontal disease or even tooth loss. If you’re looking for an effective, durable treatment for tooth decay, inlays and onlays may be right for you. They last longer than fillings but are less invasive than crown installations, making them a top solution for many patients.

For the best results, you should always work with an experienced dental team, such as the Dynamic Smile Design team. After an initial consultation, we can determine the best possible treatment for you and design a high-quality inlay or onlay that will fit your smile for several years. Learn more by scheduling an appointment today!