Dental crowns are customized caps placed over teeth to restore appearance and functionality. Crowns are highly effective at protecting weak teeth from breaking, supporting a dental bridge, and covering teeth marred by discoloration. These devices are made from a variety of materials, depending on their intended purpose. Temporary crowns, which serve as a substitute while your permanent crown is being created, are typically made from stainless steel or acrylics. Permanent crowns can be made from a list of materials, including porcelain, stainless steel, resin and ceramic. Crowns are fairly durable and can last more than a decade with proper maintenance. To ensure your crown stays in working order, limit nail biting, teeth clenching or chewing on ice, which can result in premature deterioration of your device.