Inlays and onlays are two types of fillings to repair damaged or decayed teeth and prevent the spread of damage. They are more complex than traditional fillings and require two visits to the dentist.

Like traditional fillings, inlays and onlays can be made from a number of materials including gold, porcelain, and resin. The most common types are ceramic and composite.

Procedure

The inlay and onlay procedure involves two stages and requires the use of anaesthesia.

In the first stage, the dentist takes an impression of the damaged tooth to guide the creation of a mould, which will be used to create the inlay or onlay.

At the next dental appointment, the inlay or onlay is fitted to the tooth using dental cement. The dentist checks the colour of the filling before it is finally cleaned and polished.

Inlays vs. onlays

In an inlay, the filling material is inserted inside the cavity, much like a standard amalgam or composite filling.

In an outlay, the material is inserted both inside the cavity and over the surface of the tooth.

Advantages

Inlays and onlays have several advantages over normal fillings:

  • Colour and texture matches natural teeth
  • Strong and durable material that does not discolour over time
  • Improve overall appearance of teeth
  • Last longer than standard amalgam fillings—about 30 years

Disadvantages

There are some disadvantages to these types of fillings:

  • Require two visits, one more than standard fillings
  • Cost more due to extra visit and expensive material

 

Patients with mild tooth decay are good candidates for this type of procedure. Inlays and onlays are typically used for molars and can also serve as an alternative to a cosmetic crown.