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You’ve probably thought of getting crowns or fillings for dental decay. While these two methods might be the right treatment for cavities, there are times when the decay is too severe for a filling but not severe enough for a crown.

This is where dental inlays and onlays come in to preserve as much of your natural tooth as possible. They can offer relief from chewing pain, tooth degeneration, and cavity pain. What’s the difference between an inlay and only in dentistry?

What Is a Dental Inlay?

If your tooth decay is on the smaller side, a regular filling might suffice. However, suppose your cavity is on the larger size and inside the tooth without exceeding the cusp, your dentist may use an inlay as the best option. Inlays are molded according to the tooth’s chewing surface to fit perfectly on the hollow of the tooth and not the cusps.

The dentist will also match the color of the tooth so that it’s not noticeable. An inlay may also be used when your tooth is cracked on the inside.

What Is Dental Onlays?

Onlays are used when the cusps are damaged, and there is decay and a biting surface. While an inlay lies between the cusps, an onlay covers the tooth, including the cusp and a part of the outside of the tooth. A dentist will recommend an onlay if the cavity is too big to fit standard silver fillings.

As a result, an only might be the best option if you have a lot of decay around the cusp and the middle part. The dentist prepares your tooth in the same way as a filling by drilling and cleaning the cavity after numbing the mouth.

An onlay is then placed over the cavity before an impression is taken for a permanent onlay to be manufactured. Onlays are also referred to as “partial crowns” because they cover just a portion of the tooth instead of the entire crown.

What Are the Benefits of Inlays and Onlays?

Inlays and onlays offer several benefits over regular fillings, even if both require dental visits.


Inlays and onlays can be made from various materials, but porcelain is strong and long-lasting. Regular fillings are made of composite resin or silver (amalgam), which are relatively less durable than porcelain. When put properly, inlays and onlays could last for the rest of your life. A composite filling can last for five to seven years, and an amalgam could last for up to 15 years. On the other hand, inlays and onlays can last up to 30 years with proper dental hygiene.


The dentist has to take the mold of your tooth for an inlay or onlay to fit into your tooth’s cavity and has to match the surrounding color. This makes it look natural so that no one can tell the difference from your natural tooth. A silver amalgam filling may appear grayish-black, which is likely to differ from the surrounding color.

No staining

Onlays and inlays won’t stain as the composite resin filling does. A silver Amalgam creates a dark spot on your tooth.

Inlays and onlays have their similarities, but serve specific purposes. Both are considered a great alternatives to crowns and fillings.

Talk to your dentist to know the best option for your needs.