Augmentation Techniques – the Basis of Aesthetic

Bone harvesting from the mandibular angle The retromolar mandibular segment (mandibular angle) is normally a good place for harvesting major amounts of bone. The bone volume available for har- vesting can be greatly reduced, however, in older patients exhibiting atrophic processes or if the alveo- lar nerve is located close to the surface. Therefore, anatomical structures that are worth protecting should be thoroughly analyzed by appropriate radi- ographic techniques, and the surgical approach for bone harvesting should be adjusted to the individual situation. Generally speaking, however, the mandibu- lar angle is the preferred site for enossal bone har- vesting in the hands of experienced surgeons. In terms of postoperative symptoms, bone harvesting in that area resembles an osteotomy of a moderately impacted third molar. The rate of postoperative com- plications is low. The bone is harvested using a block osteotomy or a trephine. Since protection of the nerve structures (inferior alveolar nerve, lingual nerve) is mandatory, the surgeon has to know where these are located (Figures KW1–KW4). Special retrac- tors should be used to protect the soft tissue. The harvested bone is introduced to the augmentation site either directly as a block transplant, or the bone is first crushed and then applied as a particulate graft. For structural integrity and to avoid intraopera- tive or postoperative fractures, care must be taken to maintain an adequate dimension of the lingual lamella. The bone wound should be subjected to haemostasis after harvesting, using either bone wax or a haemostatic collagen fleece to fill the defect (Figures FL1–FL3). It is not necessary to use a bone substitute. EDI Case Studies 8 Fig. KW1 Bone harvest- ing from the ascending ramus with a trephine cut- ter. Fig. KW2 Spongious and cortical bone harvested from the mandibular angle with a trephine. Fig. KW3 Block harvest- ing from the mandibular angle using thin bone cut- ters and a dia- mond disk. Special wound retractor according to Cacaci (under- neath dia- mond disk; Stoma Instru- mente).