Expression of growth factors during the healing process of alveolar ridge augmentation procedures using autogenous bone grafts in combination with GTR and an anorganic bovine bone substitute: an immunohistochemical study in the sheep

Abstract

Objectives: This study aims to evaluate the expression of various immunohistochemical growth factors and vascularization markers in augmentation on the mandible comparing onlay bone grafts and Guided Bone Regeneration (GBR).

Materials and methods: Using a sheep in vivo model, autogenous bone grafts were harvested from the iliac crest. A combination of a resorbable collagen membrane (CM) and a Deproteinized Bovine Bone Material (DBBM) was performed. This modification of the host side was compared with an onlay bone graft control group. Expression of different vascularization markers was compared between these groups.

Results: The expression of revascularization markers was significantly higher within the modification of the host side using GBR and DBBM. Regarding different graft regions, a significantly higher expression within the bone graft using GBR and DBBM could be observed in staining on bone morphogenetic protein-2 (BMP-2) (5.75 vs. 3.55), vascular endothelial growth factor (VEGF) (3.08 vs. 1.64), VEGF Receptor 1 (VEGFR-1) and VEGF Receptor 2 (VEGFR-2) (4.88 vs. 2.24 and 5.06 vs. 2.74), and endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) (5.29 vs. 3.28 and 5.22 vs. 3.09; p = 0.000, all others p < 0.05), whereas the control group showed a higher rate of resorption during the surveillance period until euthanasia of sheep after 16 weeks.

Conclusion: The use of GBR and DBBM in the transplantation process of autogenous bone grafts compared with the therapeutical use of certain growth factors may enhance vascularization and lower atrophy and resorption.

Clinical relevance: The use of a combination of GBR and DBBM in augmentation procedures on the mandible shows less resorption than simple onlay bone grafts and seems to be superior in a clinical use.