When we mention the bone volume, we mean a certain width and bone height required for implant insertion. If this volume is smaller than necessary, the bone reconstrucion (substitution) should be done. This process is called bone augmentation. As with the sinus lift, the bone defect may be bigger or smaller. If smaller, the implant can be placed simultaneously with the bone reconstruction. If the defect is bigger then bone reconstruction is performed first and after four to six months the implant is placed.