Bone grafts are used to build up or fill in jawbone defects allowing the successful placement of implants. Bone grafts can also be used for facial or cranial reconstruction. Generally an implant placed into the bone supports a single crown called a ‘single tooth implant’. In cases where there are several missing teeth, an implant is not required for every missing tooth. Here one implant can support several teeth by way of a bridge or denture. The number of implants will depend on the mass and density of bone tissue available at each implant site.