The use of a membrane to protect the more slowly growing bone from the faster proliferating soft tissue has been the basis of guided bone regeneration for more than 50 years. Today microvascularisation and the associated microcirculation are additionally considered to be crucial processes in successful bone regeneration. More recent findings demonstrate that fast and complete vascularisation using a GBR membrane supports bone formation in many respects: wound stabilisation, excellent tissue integration and uneventful wound healing go hand in hand with neo-vascularisation and thus contribute to optimum soft tissue healing and bone regeneration.
Collagen membranes
In GBR the revascularisation of the augmentation material depends on the membrane used. Only the formation of capillaries brings the osteoblasts to the place of action. Capillary formation precedes any bone formation. Immediately after the operation the augmentation material is supplied solely by diffusion. This changes as soon as angiogenesis starts. Then blood vessels assume this task. Accordingly, the early vascularisation of a membrane also facilitates healing and bone regeneration. Amongst all the materials used for GBR membranes native collagen is vascularised the best. To obtain a closer insight into these processes, different membranes were compared in several studies. In the course of this the native collagen membrane Geistlich Bio-Gide was ingrown the most quickly and uniformly by new blood vessels.
Impermeable membranes
Owing to its early vascularisation Geistlich Bio-Gide allows blood to supply the entire defect area (fig 1). Thus bone formation also occurs directly beneath the membrane (fig 2), throughout the area of the augmentation material. Neo-vascularisation is limited to the bony edge of the defect with an impermeable membrane or in delayed angiogenesis (fig 3).
A membrane allowing a vascularisation thereby supports the close relationship between angiogenesis and osteogenesis. That is a major advantage over impermeable membranes preventing this biological communication.
Vascularisation of Geistlich Bio-Gide is a natural process. This occurs in concert with the physiological speed of the surrounding tissue's regeneration. This early vascularisation of Geistlich Bio-Gide is an important membrane attribute. The sooner the osteogenic cells resettle the defect, the greater is their impact on the continued development of the augmentation material into stable bone: the new blood vessels bring oxygen and nutrients to the augmentation material and accelerate bone regeneration by supplying an endogenous cocktaiI of growth factors.
Comprehensive healing
For successful bone regeneration it is not only important what happens beneath the membrane. In the same way as osteoblasts accumulate on the coarse lower surface, fibroblasts, the progenitors of the soft tissue cells, accumulate on the smooth top side of the Geistlich Bio-Gide. The outstanding biocompatibility ensures good initial adhesion and proliferation of the two cell types on each side of the membrane. This forms the basis for a good preliminary wound stabilisation and so also for a later optimum integration of tissues. The micro movements in the area of the wound are thus lessened along with the early vascularisation of the membrane. The mechanical stabilization likewise supports optimum bone regeneration. A good and stable membrane integration into the surrounding soft tissue also permits optimum bone regeneration in purely mechanical terms. Therefore both biological and mechanical factors contribute positively to the healing of a defect.
Right place, right time
Artificial extension of barrier time (for example, by cross linking the collagen) offers no advantages for GBR over the shorter barrier time of native collagen. On the contrary: it is in particular the outstanding biocompatibility and resultant rapidly occurring angiogenesis and good tissue integration which ensure the reliable, reproducible clinical results with Geistlich Bio-Gide. This has been demonstrated in many clinical and preclinical studies. The rapid membrane vascularisation contributes to the successful GBR. Owing to the combination of high biocompatibility and fast wound stabilisation, nutrient intake and tissue integration bone regeneration with Geistlich Bio-Gide is crowned by aesthetically appealing results. Geistlich Bio-Gide offers more than just a barrier function.