Inlays and onlays are made in a dental laboratory and based on a model of your teeth. They are then placed in the mouth and attached onto the area that requires repair and attached to the tooth with highly specialised dental adhesive. Inlays sit inside the tooth, acting to effectively fill the hole that has been prepared after decay removal. On the other hand, onlays fill the hole but also sit on top of the surface of teeth, recreating some of their shape and providing extra strength to the tooth where the damage is more extensive.

Inlays / Onlays vs direct fillings

Shrinkage – conventional direct fillings have an element of shrinkage when they are set hard with a light, which can lead to micro gaps between the filling and the tooth. As inlays and onlays are made outside of the mouth, they are less affected by this.

Due to they way they are processed, inlays and onlays tend to be much stronger and last longer than direct fillings

However, two visits are required as they are laboratory made and they are therefore also more costly. Furthermore, research has shown that there is very little difference in failure rates between direct composite filling and inlays/onlays.