Inlays and Onlays

These are dental names for two types of filling which are used to repair a damaged tooth or to stop the further spread of tooth decay. They differ from standard fillings in that they are a two stage process which involves a dental laboratory.

A good way of thinking of this is that a direct filling requires a single visit whereas an indirect filling, such as an inlay and onlay requires two visits.

They are an alternative to a cosmetic crown and are preferred by people with a mild form of tooth decay. They prefer to retain as much of the natural tooth as possible, and want a filling which matches the colour of their other teeth.

Inlays and onlays are made from a variety of materials which includes gold, porcelain and resins.

There are two types of inlays and onlays:

• All ceramic inlays and onlays
• Composite inlays and onlays

Other options include direct white fillings which are discussed separately.

What are inlays and onlays?

An inlay is a type of filling in which the material used is placed inside the cavity of the tooth. In this sense it is very similar to a normal amalgam or composite white filling.

An onlay filling is where the material is inserted into not only into the cavity of the tooth but over the surface of the tooth as well.

These are known as ‘indirect fillings’  which means that they are produced in a dental laboratory before being bonded onto your teeth.

They are often used in the back teeth which are traditionally, the teeth that we use the most and are also the most difficult to clean. This also means that they are the teeth most prone to decay.

Advantages of inlays and onlays

There are several of these which include their natural looking colour which ensures continuity with the rest of your teeth. They are strong, durable and less likely to discolour over time. Plus they are attractive looking and enhance the overall appearance of your teeth.

An inlay and/or onlay can last for up to 30 years which is substantially longer than a standard amalgam filling.

Disadvantages of inlays and onlays

They require two visits to the dentist instead of one which some people may find an inconvenience.

Price is another factor: inlays and onlays tend to be more expensive than standard fillings which are due to the materials used plus the period of time to do this.

How are inlays and onlays fitted?

There are two stages to this process which differs from a normal filling which is carried out as a single procedure. This procedure is performed under a local anaesthetic.

The first stage is the creation of a mould taken from an impression of your damaged tooth which is used as a guide for a cast. The cast is used to produce the inlays or onlays.

The second stage is the fitting of the inlay or onlay. The dentist will check the fitting before securing it in place with dental cement. This ensures that it remains in place. He or she will then check the colour before giving it a final clean and polish.