The Chairside Instructor 40 Before Bone substitute is placed Treatment area is protected After Building Up Bone to Support Implants If there is not enough bone to support the implant, bone can be added by a process called bone grafting. Bone substitutes — either synthetic or natural — can be placed under the gums. Over a period of about 8 to 12 weeks, these materials replace missing bone and can stimulate new bone growth. Bone Grafting Tooth Replacement