Histologic Evaluation of Osseous Regeneration Following Combination Therapy With Platelet-Rich Plasma and Bio-Oss in a Rat Calvarial Critical-Size Defect Model
Platelet-rich plasma (PRP) is an autogenous source of growth factors shown to facilitate human bone growth. Bio-Oss, an osteoconductive xenograft, is used clinically to regenerate periodontal defects, restore dental alveolar ridges, and facilitate sinus-lift procedures. The purpose of this study was to analyze whether a combination of PRP and Bio-Oss would enhance bone regeneration better than either material alone. PRP and/or Bio-Oss were administered in an 8-mm critical-size defect (CSD) rat calvarial model of bone defect between 2 polytetrafluoroethylene membranes to prevent soft tissue incursion. Eight weeks after the induction of the CSD, histologic sections were stained with hematoxylin and eosin stain and analyzed via light microscopy. Qualitative analyses revealed new bone regeneration in all 4 groups. The Bio-Oss and PRP plus Bio-Oss groups demonstrated greater areas of closure in the defects than the control or PRP-only groups because of the space-maintaining ability of Bio-Oss. The groups grafted with Bio-Oss showed close contact with new bone growth throughout the defects, suggesting a stronger graft. The use of PRP alone or in combination with Bio-Oss, however, did not appear to enhance osseous regeneration at 8 weeks. Areas grafted with Bio-Oss demonstrated greater space-maintaining capacity than controls, and PRP was an effective vehicle for placement of the Bio-Oss. However, at 8 weeks this study was unable to demonstrate a significant advantage of using PRP plus Bio-Oss over using Bio-Oss alone.
The greater space-maintaining capability of the groups containing Bio-Oss is evident in these representative comparisons, and a thin layer of new bone transverses the defect in the platelet-rich protein only group. Original magnification ×40, then digitally enhanced using SimplePCI imaging software.
Figure 2. New bone is forming within and outside the polytetrafluoroethylene membranes in this control specimen. Note the collapsed nature of the defect. NB indicates new bone; CT, connective tissue; M, membrane. Original magnification ×40, then digitally enhanced using simple PCI. Figure 3. Note the thin layer of new bone below the membrane that nearly transverses the defect in the platelet-rich protein only group and the collapsed nature of the defect. New bone is forming within and outside the membrane, and in contact with the membrane. NB indicates new bone; CT, connective tissue; M, membrane. Original magnification ×40, then digitally enhanced using simple PCI. Figure 4. Note the space maintained by the Bio-Oss particles and the new bone formed in contact with the Bio-Oss particles in the Bio-Oss only group. NB indicates new bone; B-O, Bio-Oss; M, membrane. Original magnification ×40, then digitally enhanced using simple PCI. Figure 5. Note the space being maintained by the nonresorbed Bio-Oss particles in the platelet-rich protein plus Bio-Oss group, surrounded by new bone. NB indicates new bone; CT, connective tissue; B-O Bio-Oss; M, membrane. Original magnification ×40, then digitally enhanced using SimplePCI.
New bone formation can be seen around the periphery of the defects in the control and platelet-rich protein group x-rays. The lack of Bio-Oss resorption at 8 weeks is evidenced in the Bio-Oss and the platelet-rich protein plus Bio-Oss group x-rays.
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