with the abutment as one piece during fabrication. Dental implants, in the same way, can also be used to retain a multiple tooth dental prosthesis either in the form of a fixed bridge or removable dentures. There is limited evidence that implant-supported single crowns perform better than tooth-supported fixed partial dentures (FPDs) on a long-term basis. However, taking into account the favorable cost-benefit ratio and the high implant survival rate, dental implant therapy is the first-line strategy for single-tooth replacement. Implants preserve the integrity of the teeth adjacent to the edentulous area, and it has been shown that dental implant therapy is less costly and more efficient over time than tooth-supported FPDs for the replacement of one missing tooth. The major disadvantage of dental implant surgery is the need for a surgical procedure. Implant retained fixed bridge or implant supported bridge An implant supported bridge (or fixed denture) is a group of teeth secured to dental implants so the prosthetic cannot be removed by the user. They are similar to conventional bridges, except that the prosthesis is supported and retained by one or more implants instead of natural teeth. Bridges typically connect to more than one implant and may also connect to teeth as anchor points. Typically the number of teeth will outnumber the anchor points with the teeth that are directly over the implants referred to as abutments and those between abutments referred to as pontics. Implant supported bridges attach to implant abutments in the same way as a single tooth implant replacement. A fixed bridge may replace as few as two teeth (also known as a fixed partial denture) and may extend to replace an entire arch of teeth (also known as a fixed full denture). In both cases, the prosthesis is said to be fixed because it cannot be removed by the denture wearer. Implant-supported overdenture A removable implant supported denture (also an implant supported overdenture) is a removable prosthesis which replaces teeth, using implants to improve support, retention and stability. They are most commonly complete dentures (as opposed to partial), used to restore edentulous dental arches. The dental prosthesis can be disconnected from the implant abutments with finger pressure by the wearer. To enable this, the abutment is shaped as a small connector (a button, ball, bar or magnet) which can be connected to analogous adapters in the underside of the dental prosthesis. Orthodontic mini-implants (TAD)