Atrophic mandible reconstruction using calvarial bone grafts and implant-supported overdentures: Radiographic assessment of autograft healing and adaptation
Bone grafting constitutes a vital surgical procedure in the management of severely atrophic mandibles. In this regard, calvarial bone autografts are applied in the reconstruction of wide mandibular defects caused by edentulousness and long-term denture-related resorption. Grafts are used as a framework to augment the residual ridge and provide implant stability for further prosthetic restoration. On the basis that radiographic evidence corresponds to biologic changes in bone response to transplantation and loading, the goal of this article is to document the radiographic assessment of calvarial autologous bone grafts in the recipient site. Panoramic radiographs were used to evaluate bone changes occurring during both the graft healing period and graft adaptation after implant loading. Emerging data show that conventional panoramic radiography may have an effect on the investigation of bone grafts and provide initial information about graft incorporation and adaptation.
Available from: Cristina Barona
- "In general, the success of a bone graft is measured in terms of its capacity to withstand the conditions of tension and mechanical deformation to which it is subjected (8). "
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ABSTRACT: To evaluate graft types used for maxillary sinus augmentation and review success rates of dental implants inserted in these areas, analyzing the graft materials used, implant surface types and the moment of implant placement.
A meta-analytic study reviewing articles on sinus augmentation published during the last ten years.
3,975 implants placed in sinus augmentations (with bony windows) were registered, of which 3,749 implants survived, a survival rate of 94.3%.
When performing sinus augmentation, bone substitute materials are just as effective as autologous bone, whether used alone or in combination with autologous bone. Implant surface treatments can have an important effect on implant survival and it would appear that roughened surfaces are the best option. When implants are inserted simultaneously to grafting, a higher failure rate can be expected.
Medicina oral, patologia oral y cirugia bucal 12/2011; 17(1):e135-9. DOI:10.4317/medoral.16920 · 1.17 Impact Factor
Available from: Vincenzo Luca Zizzari
- "repairs than endochondral grafts in craniofacial defects (Wong & Rabie 1999; Bianchi et al. 2004; Crespi et al. 2007). Moreover, many authors agree that, independently of the embryologic origin, the number of the corticals and the macroscopic architecture of the tissue harvested might affect the clinical success in bone grafting (Lu & Rabie 2004). "
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ABSTRACT: The aim of this study was to investigate, in parallel to clinical and histological modifications, the expression of specific proteins involved in different extraoral autologous bone grafts integration in humans.
Patients needing oral rehabilitation of posterior maxilla, with inadequate bone volume for implant placement, received bone grafts from calvaria (Group 1) and iliac crest (Group 2), respectively. From five patients from each group, with a total of 10 subjects, bone biopsy specimens were collected at two different experimental time points: at bone blocks withdrawal for grafting (T0), from donor sites, and after 4 months, from reconstructed sites. Samples were processed for light microscope and immunohistochemical analyses to evaluate MMP9, VEGF, BSP, iNOS expression.
Morphological analysis of T0 calvaria evidenced areas of extracellular matrix, uniformly stained and organized in concentric mineralized lamellae edging few vascular canals, while T0 iliac crest showed greater cellularity compared to calvaria, with rare mineralized areas, surrounding wide bone marrow lacunae. In T1, Group 1 samples showed large areas of extracellular matrix, uniformly stained, at the same time as Group 2 samples disclosed few areas of mineralized tissue. Although no significant differences were found in proteins expression among calvaria and iliac crest T0 samples, MMP9, VEGF and BSP expression at T1 were discovered higher in Group 1 samples than in Group 2 ones, while iNOS expression increased in Group 2 samples compared to the others. In any group, molecules expression increased passing from T0 to T1.
These findings suggested that, even though clinically both extraoral sources of autologous bone could be considered suitable for grafting in case of large oral rehabilitation, some differences might be detected microscopically and biologically. Calvaria bone graft seemed to enhance not only the quantity of bone tissue at the defect site, but also its quality, better than iliac crest bone do. Then, while both grafts appeared to promote a suitable neoangiogenesis, as showed by morphological analysis and by MMP9 and VEGF expression, in terms of new bone formation and lack of occurrence of inflammatory events, calvaria could be considered a more suitable donor site for bone grafts.
Clinical Oral Implants Research 09/2011; 23(11):1254-60. DOI:10.1111/j.1600-0501.2011.02300.x · 3.89 Impact Factor
Available from: Alberto Rebaudi
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ABSTRACT: Two evaluation techniques (histology and microcomputed tomography [micro-CT]) were synergistically applied to calvarial bone graft to verify whether additional bone information can be obtained for the assessment of bone grafts. Ten extensive bone defects in the anterior and posterior maxilla or mandible involving crestal bone were treated by grafted blocks and chips of autogenous calvarial bone. The grafts were fixed with lag screws and left to heal for 4 months. No complications were observed. At surgical reentry for implant placement, a cylindric bone biopsy of both graft and native bone was retrieved and analyzed with both micro-CT and standard histology. Two- and three-dimensional (2D, 3D) micro-CT analyses allowed bone connectivity indices to be evaluated. This is useful for estimating bone strength and observing bone structure. The integration of the grafted calvarial bone with the residual bone of the recipient site was considered satisfactory. Histologic analysis allowed observations to be made at a higher resolution. Calvarial bone grafts seem to have positive effects when used as grafting materials. The application of both histologic and micro-CT techniques allows a better evaluation of grafted bone by concurrently allowing 2D and 3D visual and morphometric analysis of bone vitality, structure, turnover, and strength.
The International journal of periodontics & restorative dentistry 01/2011; 31(4):e29-36. · 1.42 Impact Factor
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