It is done to improve the appearance (though not necessarily the functionality) of teeth, gums and/or bite. It primarily focuses on improvement of dental aesthetics in color, position, shape, size, alignment and overall smile appearance. In the past, dental fillings and other tooth restorations were made of gold, amalgam and other metals—some of which were veneered with porcelain. Now, dental work can be made entirely of porcelain or composite materials that more closely mimic the appearance of natural tooth structure. These tooth colored materials are bonded to the underlying tooth structure with resin adhesives.