Kirkland Dentistry - Family & Cosmetic Care - A Beaverton/Hillsboro General Dentist

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Inlays & Onlays

tooth prepped for onlay onlay in place

A durable way to restore teeth that require large old fillings to be replaced, have large decay, or fractured areas. An excellent alternative to crowns because of the conservation of healthy tooth structure.

The Problem:

  • Moderate to large amount of decay on a portion of posterior teeth.
  • Need for a long-term, durable restoration
  • Desire to limit the amount of healthy tooth structure removed
  • Need to strengthen and reinforce tooth

The Solution:

Decay is removed and after the tooth is shaped a detailed impression is made. This mold is sent to a dental laboratory that will create a porcelain (tooth colored) or gold restoration called an inlay or onlay. The restoration is then cemented into the prepared surface of the tooth.

An inlay covers only internal surfaces of the tooth whereas an onlay is larger and covers one or more cusp tips (the chewing surface of the tooth.)


Inlays and onlays are very durable and esthetic due to the fact that they are created in a laboratory. This protects the tooth from fracturing and actually strengthens the tooth. In addition, inlays and onlays fit almost perfectly into the prepared surface of the tooth, reducing the size of the seam between the restoration and the tooth. This helps keep decay from reoccurring under the restoration.

Inlays and onlays only require the removal of decayed or weak areas of the tooth, leaving more healthy tooth structure intact as compared to a crown. This will decrease the likelihood of replacement or the expense of root canal therapy in the future.


Due to the fact that they are crafted in a laboratory, inlays and onlays require a greater initial investment than regular fillings. However, in the long run, inlays and onlays are a better investment than fillings due to their durability and highly accurate fit. For some people, gold restorations may not be desirable due to their gold color. However, this is still the most durable restorative material available today and gold onlays can be designed to prevent the gold from showing when restoring upper posterior teeth.


In cases of extensive decay or loss of tooth structure, crowns are the only alternative.