Purpose: The purpose of this study was to conduct a comparative immunohistochemical evaluation of microvessel density (MVD) in alveolar sites augmented with autologous bone or Bio-Oss.
Materials and Methods: Eighteen patients participated in this study. All patients presented maxillary ridge defects. These defects were filled in a random fashion with autologous bone or Bio-Oss. Endosseous implants were inserted after a mean of 3 months in the sites augmented with autologous bone and after a mean of 6 months in the sites augmented with Bio-Oss. As part of the implant site preparation, a trephine was used to harvest bone cores. As control, bone cores retrieved in nonaugmented sites were used. The mean value of MVD in control bone was 25.6 ± 3.425. In the sites augmented with autologous bone, the MVD was 29.8 ± 4.4, while in the sites regenerated with Bio-Oss, the MVD was 29.7 ± 2.4. The statistical analysis showed that the difference in MVD between control bone and autologous bone (P = 0.057) and between control bone and Bio-Oss (P = 0.023) was statistically significant. The difference between the sites regenerated with autologous bone and those regenerated with Bio-Oss was not significant (P = 0.6889).
Conclusions: Our results show that both sites augmented with autologous bone and Bio-Oss presented a higher and statistically significant quantity of microvessels compared with control specimens. No significant differences were found when comparing the MVD of the sites regenerated with autologous bone and those regenerated with Bio-Oss. The retrieval time was, however, a mean of 3 months for the autologous bone sites and a mean of 6 months for the Bio-Oss sites. These data could support the hypothesis of faster healing for the sites augmented with autologous bone.
Localized ridge atrophy may be a hindrance to correct implant placement so that a ridge augmentation procedure may be in order. 1–3 These techniques include the use of bone grafts and barrier membranes. 4–6 The preferred bone graft material is autologous bone because it carries proteins as bone-enhancing substrates, minerals, and vital bone cells. 2,7–9 Other bone grafts, ie, allografts or xenografts do not carry vital cells and have been shown to be unpredictable in terms of the amount of osteogenic promoters that may be present. 2 Blood vessels are an important component of bone formation and maintenance. 10 Haversian and Volkmann’s canals provide the vascularization of the cortical bone (nutrients and cytokines pass through them to reach the osteocytes and the osteoblasts). 10 The process of vascular induction is termed angiogenesis and it plays a key role in all regenerative processes. 10,11 Angiogenesis is important in several conditions, such as wound healing, inflammatory diseases, and tumors. 12 Also, the differentiation of bone tissue is affected by local vascularity. The low oxygen tension and high metabolic activity present at the injury sites promote angiogenesis. 11 For the repair of tissue, the development of a vascular system at the site of injury is necessary for the delivery of oxygen and nutrients and to clear away cell debris. 10 Angiogenesis is regulated through a complex interplay of molecular signals mediated by growth factors 10 involving extracellular matrix remodeling, endothelial cell migration and proliferation, capillary differentiation, and anastomosis. 12 One of the methods to evaluate the presence of blood vessels in tissue is the counting of microvessels to evaluate the microvessel density (MVD). MVD has been extensively studied in tumors and seems to be correlated with prognosis in several malignant tumors. 13 The aim of the present study was to conduct a comparative immunohistochemical evaluation of MVD in alveolar sites augmented with autologous bone or Bio-Oss (Geistlich, Wohlhusen, Switzerland).