Based on healing events in postextraction sites, socket preservation following tooth extraction seems to be important to prevent ridge resorption, to reduce the need for further augmentation/surgical procedures, and to simplify implant placement at a later time (Darby et al., 2009).

Rationale

The healing of an extraction socket results in negative changes in the alveolar bone dimensions. The bundle bone disappears and the height of the buccal wall of the socket is reduced. Tissue loss is more pronounced from the buccal aspect than from the lingual/palatal aspect (Araújo & Lindhe, 2005, 2009a).

Healing is characterized by internal changes (bone formation within the socket) and external changes (three-dimensional resorption of the bony walls). The imbalance between bone formation in the socket and bone resorption of the socket walls results in a net loss of hard tissues. After tooth removal, the extravascular blood cells form a blood clot that fills the socket. Within 2–3 days, primary granulation tissue infiltrates the clot, beginning at the base and periphery of the socket. After 7 days, woven bone, characterized by uncalcified bone spicules, appears and mineralization is initiated from the base to the coronal part of the socket. Epithelialization achieves the complete closure of the socket about 6 weeks after the extraction. Complete healing of the extraction socket is achieved after at least 3 months, depending on bone destruction following the tooth extraction.

Products and Devices

Bone graft materials may be used to limit alveolar bone resorption. Autogenous graft, substitute materials, membrane barriers, collagen sponges, and PGA/PLA sponges can be employed. The true impact of substitute materials on healing periods and regenerative outcomes is unknown (Darby et al., 2009). It is unclear to what extent residual particles of grafting material still present at the time of implant affect the ISR. Animal studies indicate that autograft material fails to prevent ridge resorption (Araújo & Lindhe, 2011). Instead, bone substitute (Bio-Oss®) counteracts ridge contraction (Araújo & Lindhe, 2009b). The use of membrane barriers in addition to the graft material can increase the amount of newly formed bone in pres/>