Crowns are also mainly made of ceramic materials but if several teeth are involved, bridges are used to correct the problem. Bridges are merely several crowns joined into one unit that is fastened to two opposing teeth that would serve as anchors. Sadly, bridges require the two nearest teeth to get root canals to prevent problems from arising later should they decay. For people who are not favorable to having healthy teeth trimmed down and in effect killed off through a root canal, there are always dental implants made of exotic metals that are inert to the human body that allows the restoration of smiles that have been lost.