**3.1 Intraoral donor sites**

*Oral and Maxillofacial Surgery*

the defect site. Several studies reported PDGF to be highly effective on regeneration

In many bone defects, guided bone regeneration procedures result in successful outcomes. It has several superiorities over block bone grafting like eliminating the secondary surgical site for bone harvesting and post-operative discomfort at the donor site. However, GBR is well-documented in regeneration of new bone up to 4.5–5 mm width and height. When the defect size gets larger, it's harder to achieve predictable results with this protocol. Although extending the healing period is recommended in large size defects, new bone quality is still observed to be less than ideal. Also GBR covering full arches, especially mandible, is not predictable. Therefore autogenous block bone grafting is utilized in large size defects [11, 34]. Significant amount (>5 mm) of new bone formation in vertical or horizontal dimensions can be achieved utilizing autogenous bone block grafting. It is indicated in augmentation of severely atrophic crests. In a review by Aloy-Prosper et al., autogenous block bone grafting procedures and their results are evaluated. In horizontally augmented sites utilizing block bones, implant survival rates are found to be ranging from %96.9 and %100. In vertically augmented sites through same procedures, implant survival rates are slightly lower ranging from %89.5

Autografts to be used in the procedure are obtained from various donor sites intra- and extraorally. Less complications are reported when intraoral donor sites are preferred for harvesting. When deciding for the donor site, amount of needed bone volume and defect size should be carefully evaluated. Autogenous bone graft shows high resorption rates, therefore it's important to harvest larger volumes considering the possible resorption [5]. Despite high resorption rates, osteogenic potential of autogenous bone makes this procedure feasible. Comparing GBR with autogenous block bone grafting, Jensen et al. reported that reaugmentation is needed in %11.1 of GBR cases and %2.8 of block bone grafting cases due to insufficient new bone formation [36]. Recently, there are studies recommending

in advanced periodontal osseous defects [3].

*Prepared human blood-derived PRF in the centrifuge tubes.*

**3. Autogenous onlay block bone grafting**

**152**

and %100 [35].

**Figure 6.**

Mandibular symphisis, buccal ramus shelf, maxillary tuberosity and torus are the main intraoral sources for bone block harvesting. Membranous grafts such as grafts obtained from mandibula are reported to have less resorption rates than the endochondrial grafts obtained from extraoral sites. Dimensional stability of the new bone and incorporation of grafts to the host site is also shown to be better when membranous grafts are utilized. Main advantages of intraoral bone blocks are less occuring complications, no need for patients to go under general anesthesia, no cutaneous scarring, easy surgical access, less morbidity in the donor site and more content of bone growth factors [38–41].
