Dental implants come in a variety of shapes, sizes and lengths. Most dental implants placed are 8-13 mm long. The maxillary sinus sits above the back teeth in your upper jaw. Some people have large sinuses that are close to the teeth and some have smaller sinuses that are a great distance from the teeth. Since implants are at least 6 mm long, the sinus should be more than 6 mm from where the upper teeth were. If the sinus is closer, it must be lifted and re-positioned to allow room for the implants. The sinus lifts done in our office are minimally invasive and are usually done the same day that the implant is put in.