Block augmentation - autologous blocks

  • Block augmentation
    Post-op situation
  • Block augmentation
    Narrow alveolar ridge
  • Block augmentation
    Bone block screwed to the ridge
  • Block augmentation
    Resorption protection with cerabone®
  • Block augmentation
    Implantation 3–4 months after augmentation
Block augmentation is a technique developed for the reconstruction of severely resorbed alveolar ridges or for the regeneration of complex defects. To this end, autologous bone blocks are typically harvested from extraoral/intraoral regions or, in case of a particularly severe atrophy (and need of a significant amount of bone), from the iliac crest. Other external donor sites include the calvarium, rib, and tibia. Intraoral harvesting sites that include mandibular symphysis, mandibular ramus, the retromolar area, or maxillary tuberosity represent a valid alternative to repair more localized alveolar defects. One of the advantages of an intraoral block is the close proximity of donor and recipient sites as well as an easier surgical access; these ensure a reduced donor-site morbidity and costs.

Combination with cerabone®

The use of a mixture of autologous bone and xenogenic materials (cerabone®) offers the typical benefits of both materials: The biological potential of the autologous transplant induces a fast incorporation of the graft and implant, while volume-stable cerabone® applied to fill possible voids acts as a barrier against resorption, thus leading to an overall improvement of the esthetic outcome.

Transplants are typically fixed with osteosynthesis screws to the augmentation site. In general, intraorally harvested bone blocks show a lower resorption compared to transplants from the iliac crest; however, they also provide a significantly lower bone volume. Owing to its osteogenic and osteoinductive properties, autologous bone is an ideal scaffold for bone regeneration, e.g. even extensive vertical defects can be treated. In this case, the rapid incorporation of the blocks allows an early implantation, often after only 3–4 months. Today, modern instruments facilitate the harvesting procedure; microsaws and piezosurgical devices, for instance, allow the surgeon to perform a precise cut, resulting in less bone loss and surgical trauma to the donor site. After block harvesting, the donor site can be filled with a collagen sponge (Jason® fleece) to support hemostasis.

After fixing the blocks to the recipient site, the area around the block may be filled with a bone graft material. A low resorbable material, such as bovine bone cerabone®, can help prevent the fast resorption of the bone block. Notably, comparative studies have shown that less resorption occurs when the blocks are covered with a membrane such as the collprotect® membrane.

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