Porcelain Inlays or Onlays
These are typically used when cosmetics and wear resistance are most important for a patient. A porcelain inlay or onlay is used when the cavity is too big for a filling, but isn't so big that a crown is required. A porcelain inlay is a filling within the cusp tips of the tooth. Porcelain Onlays (also known as overlays) will overlay one or more cusps in order to protect and strengthen the tooth. This type of filling costs about the same as an indirect composite inlay/onlay and normally takes two visits to complete.
Gold Inlay or Onlay
An inlay or onlay may also be made of gold. Gold fillings, despite being expensive, have long history of use with excellent durability, wear well, and do not cause excessive wear to the opposing teeth. But they do conduct heat and cold, making their presence felt in the mouth. Recent advances has brought consumer focus on aesthetic results of composites or porceelain veneers/crowns.
This is considered fairly conservative procedure as it disturbs fairly less tooth structure. This highly fluoride contained filling material interacts with the enamel and dentin and actually allows the tooth tissue to remineralize at the filling interface. This provides a true biological and chemical seal with the tooth. It is good for those who feel sensitivity with the rest of their otherwise healthy looking teeth.