Implants can be utilized to replace one or many teeth. When replacing a single tooth, an implant can prevent the removal of neighbouring tooth structure, which is required for a tooth-supported bridge. When multiple teeth are lost, there are a number of options available. Sometimes multiple implants are required for individual tooth replacements. In other cases, a smaller number of implants are placed to support multiple teeth: known as an implant-supported bridge. Such an approach can even be used to replace all of the teeth using the All-On-4 system developed by the implant company Nobel Biocare.