What are dental inlays and onlays?

Dental inlays and onlays are gold, composite, or porcelain materials used to repair moderately damaged or decayed teeth. Dentists use dental inlays and onlays to restore a tooth that is too damaged to repair with a filling but not damaged enough to need a crown. Dental inlays and onlays save the healthy portion of an injured tooth and provide strength and stability for normal chewing.  

A dental inlay is placed in the center area of the tooth. A dental onlay is placed on the inside and outside areas, or points, of a tooth. Dental inlays and onlays are also called indirect fillings or partial crowns. They are a less aggressive and usually less expensive treatment option than full crowns.

Placing a dental inlay or onlay is generally considered safe, but there are risks and potential complications. It is only one method used to repair damaged or decayed teeth. Discuss all of your options with your dentist to understand which options are right for you.

Types of dental inlays and onlays

Dental inlays and onlays can be made of the following materials:

  • Composites (resins) include powdered glass-like material and acrylics. Composite inlays and onlays are more cosmetically pleasing than metal because they match the tooth’s color.
  • Metal, typically gold, but other metals may be used as well. Dentists may use metal inlays or onlays in back teeth, or molars, because of metal’s strength and durability. Today, gold is used less often than in the past because it is less cosmetically pleasing than other types of inlays and onlays.
  • Porcelain matches the tooth’s color.

Why are dental inlays or onlays performed? 

Your dentist may recommend a dental inlay or onlay for conditions including:

  • Cracked or chipped teeth that cannot be repaired with a dental filling but do not require more extensive procedures to repair, such as a root canal and/or dental crown.
  • Tooth decay (cavities, dental caries) that occurs when bacteria in your mouth produce an acid that damages the teeth. Dentists can often repair minor to moderate decay with a dental filing.  Moderate to severe or deep decay may require a dental inlay or onlay or crown to save the function of the tooth. 

Who performs a dental inlay or onlay procedure?

The following dental providers perform dental inlay or onlay procedures:

  • General dentists prevent, diagnose and treat diseases and conditions of the teeth, gums, mouth, and associated structures of the jaw and face.
  • Pediatric dentists specialize in caring for the dental needs of children and teens.
  • Prosthodontists specialize in restoring damaged teeth with crowns, bridges and other devices.

How is a dental inlay or onlay performed?

Your dental inlay or onlay procedure will be performed in a dental office or clinic. The procedure varies  depending on the type of tooth and inlay or onlay but generally includes these steps:

  1. You will sit in a reclining position in the dentist chair and wear a clear shield over your eyes. The shield protects your eyes from spraying liquids and dental instruments.
  2. Your dentist will inject a local anesthetic into the gums near your tooth. The anesthetic numbs pain during the procedure. Your dentist may apply a painless topical anesthetic to numb the gums partially before the injection.
  3. Your dentist will use a drill to remove the damaged part of your tooth. He or she will file down certain parts of your tooth to prepare it to stick to the inlay or onlay materials.
  4. Your dentist will make a mold (impression) of your tooth. Your dentist uses the impression of your teeth to make a customized inlay or onlay that fits correctly. 
  5. Some dentists have equipment to make inlays and onlays in their offices. In this case, your dentist will make and place your inlay or onlay during the same visit. 
  6. Some dentists send dental impressions to a lab that makes inlays and onlays. In this case, your dentist will cement a temporary inlay or onlay in your tooth until your permanent one is ready. The temporary inlay or onlay lasts for a few weeks or months. 
  7. You will return to the dentist’s office within a few weeks. Your dentist will remove the temporary inlay or onlay and place your permanent one with strong and permanent cement.
  8. Your dentist will smooth and polish the inlay or onlay to ensure a comfortable bite and so that it will not scrape your mouth or tongue.