Inlays and Onlays

Inlays and Onlays are dental names given to two types of filling which are used to repair a damaged tooth or to stop the further tooth decay. They are categorized under indirect restoration which takes two visits, unlike the direct ones which are done in a single visit. They are an effective way to restore your tooth especially when a large part of your tooth has gone bad.


Inlay: As suggested by the name, this restoration is placed inside the cavity of the tooth.

Onlay: In contrast with the inlays, this is bonded on top of the tooth along with inserting the filling inside the cavity, replacing some or all of the cusps of the tooth.

The shape and type of restoration, whether inlay or onlay, is determined by the amount of decay or existing filling being replaced. Therefore, in most cases, it is preferred to have a filling that is part inlay and part onlay rather than having an inlay or an onlay. These two types are usually used for posteriors (back teeth), premolars and molars. Both the inlays and onlays are esthetic restorations which can replace the metallic restorations.

Materials Used

  • Cast metal
  • Gold Composite
  • Porcelain
  • Gold Inlays
  • Resins

    Inlays and Onlays


  1. Gold is an amazing material and has successfully been used for many years now. It has extremely high strength, toughness, durability, and resistance to wear. It is quite effective and regarded as the ultimate filling but not widely used nowadays because of the increasing price and demand for natural looking teeth.
  2. Porcelain Inlays vary in their structure, features and benefits. Each dentist has a particular type that they prefer and use commonly. More retention can be gained with these because in large open cavities the porcelain can be etched and bonded to the tooth. The desire for a more natural looking tooth is increasing and the ability to bond these restorations to your tooth is improving, making porcelain the first choice.
  3. Zirconia is a much harder material which needs to be cemented using a very strong adhesive. Since there is no bonding, it tends to be better in situations where the natural cavity shape has a better retention. Due to incredible strength, it’s useful for patients who clench and grind their teeth.
  4. Composite Inlays are a useful alternative in which the preparation takes place outside the mouth. It often allows the dentist to complete the procedure in a single sitting. It doesn’t require the lab, reducing the cost, plus the composite causes less wear on opposing teeth as compared to porcelain. Rectification is much easier if there is a problem. Some dentists choose it over porcelain, whereas the majority of dentists prefer other options. The inlay/onlay doesn’t stress the tooth in the way that placing a composite filling directly into the cavity would. The disadvantage is that the material will have a tendency to pick up stain at the margins. They will discolor and wear more over time than the porcelain and gold counterparts.

The above are majorly categorized into All ceramic inlays & onlays and Composite inlays & onlays.

Dental Health

Advantages of Inlays and Onlays

  • Porcelains natural looking color ensures continuity with the rest of your teeth.
  • They are strong, durable and less likely to discolor over time.
  • They are attractive looking and enhance the overall beauty of the teeth.
  • They can last for up to 30 years which is substantially longer than a standard filling.

Disadvantages of Inlays and Onlays

  • They require two visits to the dentist instead of one which some people may find inconvenient.
  • Inlays and onlays are more expensive than standard fillings due to the materials used besides the period of time to do this.


  • The first step is the formation of mould from an impression taken of the affected tooth which is helpful in preparing a cast. The cast is then used to produce the inlays or onlays.
  • The second step involves checking the fitting of the inlay or onlay before cementig it ensuring that it remains in place. The patient will then check the color before the final cleaning and polishing.


One needs to take special care of the teeth while temporary restorations are still in place. Dr. Paul Kim, Dentist in Torrance, suggests to strictly avoid sticky or hard food stuff that can cause damage to the provisional restoration. Once you get done with your definitive inlay or onlay, you can resume normal eating, brushing and flossing habits.


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