Because old silver fillings are not bonded in place, over time, they tend to cause splits and fractures in the tooth (similar to that of an axe and wedge). Conversely, inlays and onlays are bonded in place and actually strengthen the tooth in comparison to the old silver filling. It is a rarity that people must have full crowns or ‘caps’ anymore because of the advancements in dental materials and cements. With inlays and onlays it is no longer necessary to remove as much tooth structure. Instead inlays and onlays replace only what is needed (i.e. filling and decay). They are also strong and long lasting.