A crown is a cap or covering for a tooth generally made with ceramic, zirconium oxide, porcelain, etc. It is used when your tooth is discolored, cracked or broken, heavily filled, or if fillings are lost. It can also be placed on top of the implant structural support.
A bridge is generally recommended if one is missing one or more teeth. Gaps left by missing teeth will eventually cause the remaining teeth to rotate or shift from its position into the empty spaces. This can result in a bad bite. The imbalance caused by the missing teeth can also lead to gum diseases and temporomandibular joint (TMJ) disorders. They are generally made of porcelain fused into metal. This is done to achieve both strength and the natural look.
According to the best dentist in Kolkata crowns and most bridges are both fixed prosthetic devices. They are cemented onto existing teeth or implants and can be removed only by a dentist.