Figure 31. Mandibular molar extraction
However, hard tissue formation within extraction sockets is highly variable in humans.
Figure 29. Day 180 : large marrow spaces
After 180 days of healing, beneath the marginal cortical bone at the entrance of the socket as denoted by the arrow, most of the socket is filled with trabecular bone that includes large marrow spaces. The bone is characterized by a limited number of trabeculae of lamellar bone. The bone marrow contains large numbers of adipocytes but only a few inflam...
Figure 28. Day 120 : cortical bone & trabecular bone
At 120 days of healing, the entrance of the socket, denoted with an arrow, has become reinforced by layers of cortical bone that are deposited over the previously formed woven bone.
Figure 27. At 30 days of healing, a significant part of the extraction socket is filled with newly formed bone.
At 30 days of healing, a significant part of the extraction socket is filled with newly formed bone. This bone contains a large number of primary osteons and is continuous with the original bone of the socket walls. In some areas, the process of modeling and remodeling of the newly ...
Figure 26. Day 14: woven bone & connective tissue
After 14 days of healing woven bone, which appears as a loose, unstructured network of bone, has started to fill the socket except in the central region, where significant amounts of the provisional connective tissue matrix still remain. This is because the woven bone forms first at the periphery of the socket and gradually extends from the wa...
Figure 25. Day 7: Provisional matrix & osteoclasts
After 1 week of healing, the wound in the extraction site has significantly changed. In the central and apical part of the socket, large areas of the coagulum have been replaced with a provisional connective tissue matrix, which is lightly stained in the histologic section. Regions of darker-staining granulation tissue can still be seen. This...
Figure 24. Day 3: blood coagulation, inflammatory cells, granulation tissue
At the end of this initial healing period, small segments of the coagulum are replaced by a highly vascularized granulation tissue and an inflammatory cell infiltrate that is stained dark red/blue.
Figure 23. summary of biological events on third day after extraction
On day 3, the socket is filled with a blood coagulum comprised of red blood cells and platelets trapped in a fibrin network together with isolated inflammatory cells such as neutrophils. Close to the bundle bone, mesenchymal cells, severed periodontal fibers, and dilated vascular units can be observed.
Figure 22. Day 1: Blood coagulation and inflammatory cells
Hard and soft tissue composition in the extraction socket during longer healing periods was documented in a study by Cardaropoli and coworkers, in which the entire healing cascade after tooth extraction was evaluated in a dog model. The following images are histologic specimens representing the stages of healing observed in their stud...