In dentistry, inlays and onlays are a form of indirect restoration. This means they are made outside of the mouth as a single, solid piece that fits the specific size and shape of the cavity. The restoration is then cemented in place in the mouth.
This is an alternative to a direct restoration, made out of.
Composite, Amalgam or glass ionomer, that is build up within the mouth.
Inlays and onlays are used in molars or premolars, when the tooth has experienced too much damage to support a basic filling, but not so much damage that a crown is necessary.
The key comparison between them is the amount and part of the tooth that they cover.
An Inlay will incorporate the pits and fissures of a tooth, mainly encompassing the chewing surface between the cusps.
An Onlay will involve one or more cusps being covered. If all cusps and the entire surface of the tooth is covered this is then known as a crown.
Historically inlays and onlays will have been made from gold and this material is still commonly used today.
Alternative materials such as porcelain were first described being used for inlays back in 1857. Due to its tooth like colour, porcelain provides better aesthetic value for the patient. In more recent years, inlays and onlays have increasingly been made out of ceramic materials.
In 1985, The first ceramic inlay created by a chair-side CAD/CAM device was used for a patient. More recently, in 2000 , the CEREC3 was introduced.
This allows for inlays and onlays to be created and fitted all within one appointment.
Furthermore, no scanning capabilities of the machine.
• Inlays/onlays are indicated when teeth are weakened and extensively restored. There are no obvious contrast between the two.
• Inlays are usually reserved for larger cavities as tooth conservation is paramount in current practice and small cavities can be restored with direct composites instead.
• Onlays are indicated when there is a need to protect weakened Tooth structure without additional removal of tooth tissue.
It can also be used if there is minimal contour of remaining coronal tooth
tissue with little retention.
• Poor oral hygiene
• Para functional habits and heavy occlusal forces
• Patient under 16; because the pulp chamber is still large and wide dentinal tubules increase the stress on the pulp.
• Unable to tolerate impression taking
• Gold
• Ceramic
• Composite
• Metal-ceramic