When teeth are extracted, the body works quickly to heal itself. Gingival tissue heals faster than bone, and sometimes the soft tissue fills the socket before the bone does and leaves a bone deficiency. Occasionally, because of the amount of bone loss around the tooth already, preventing further bone loss at the time of tooth removal is advantageous. Through the use of resorbable membrane, and sometimes the addition of bone, it is possible to keep the gingival tissue out of the socket to allow the bone to fill in instead. This will allow a proper bony foundation for future implant placement. It is usually necessary to allow at least 3 months for healing of the socket before an implant can be placed in the area.
The solution is a graft to lift the sinus membrane away from the tip of the dental implant to be placed in the area. The surgeon enters the sinus from the side where the upper teeth used to be. The sinus membrane is then lifted upward and donor bone is inserted under the membrane. Often, the implant can be placed at the same time. If there is too little natural bone to stabilize an implant at the time of grafting surgery, the graft is allowed to heal at least 6 months before attempting to place the implant. After several months of healing, the grafted bone become part of the patient's own bone and the dental implants can then be placed into the new sinus bone. The sinus graft makes it possible for many patients to have dental implants when years ago there was no other option.
Socket Grafting at Implant Placement
When implants are placed at the same time a tooth is extracted, the socket is usually always bigger than the implant diameter used to replace the tooth. This means that there is a gap between the implant and the socket walls. Bone naturally shrinks when there are spaces to shrink into. In order to prevent this shrinkage, and maximize the natural appearance of the gum that the implant crown emerges from, bone grafting is nearly always done at the time of extraction, and often done at the time of implant placement even if the extraction was done earlier since bone shrinks after the extraction. The image below are of areas where the bone is thin, and where the socket is wider than the implant diameter to be placed.