Inlays work in the same way as fillings – and are administered in the same way – but are used to repair a tooth with a much larger surface area. This is normally on the back teeth where there is a bigger chewing surface area. They are commonly placed to replace fillings that have failed in the past and require much less tooth destruction than full conventional crowns.
Where inlays, like fillings, repair damage done to the inside of a tooth, onlays work to repair the cusp of the tooth. This means that they lie over the tooth and can help rebuild the outer shape of the tooth.
Most inlays and onlays are made of either metal, composite resin or porcelain.