Do Collagenated Xenogenic Bone Substitutes Enhance Gingival Healing and Angiogenesis Through a Barrier Membrane? An In Vitro Study

TL;DR

This study shows that collagenated bone substitutes improve soft tissue healing and blood vessel growth in the gums, suggesting benefits beyond just bone regeneration.

Contribution

The study demonstrates that collagenated bone substitutes enhance gingival healing and angiogenesis via barrier membranes, extending their role beyond bone regeneration.

Findings

Collagenated GTO and Gen-Os significantly increased human gingival cell proliferation and migration compared to controls.

GTO showed higher VEGF and FGF-2 secretion, leading to enhanced tube formation in angiogenesis assays.

Collagenated materials promoted mesenchymal stem cell recruitment, though BMP-2 secretion was unaffected.

Abstract

Research in implant dentistry has predominantly focused on bone regeneration, osseous volume maintenance, and successful osseointegration. However, soft tissue healing, which influences implant functional sealing, long-term stability, and esthetic integration, remains underexplored. This study investigated the effects of three xenogenic bone substitutes on gingival healing in vitro. Three experimental groups were established using extracts from bone substitutes diffusing through the OsteoBiol® Evolution collagen membrane: two collagenated substitutes, OsteoBiol® Gen-Os® (Gen-Os) and OsteoBiol® GTO® (GTO), and one inorganic substitute, Bio-Oss® (Bio-Oss). The substitutes were prepared in test tubes, and the extracts diffusing through the collagen membrane were used to evaluate human gingival cell (hGC) proliferation (MTT assay), migration (scratch assay), and growth factor release (ELISA). Angiogenic potential was assessed by endothelial cell proliferation, recruitment (Boyden chambers), and organization (Matrigel® assays). The indirect interaction between stimulated gingival cells and human bone marrow mesenchymal stem cells (hMSC) was investigated by analyzing hMSC recruitment and osteogenic BMP-2 secretion. Collagenated GTO and Gen-Os significantly enhanced hGC proliferation and migration in the scratch assay, with 1.8-fold and 1.6-fold increases, respectively, compared to control. All three substitutes enhanced neoangiogenesis in vitro. VEGF and FGF-2 secretion was significantly higher with GTO, showing 5-fold and 5.7-fold increases, respectively, resulting in a 3.7-fold increase in tube formation compared to control. Collagenated materials promoted hMSC recruitment, whereas BMP-2 secretion was not affected by any material. The observed effects were higher with the collagenated Gen-Os and GTO, with 2.5-fold and 2.8-fold increases, respectively, than with the non-collagenated Bio-Oss, which showed a 1.5-fold increase. These findings demonstrate that collagenated bone substitutes enhance gingival healing and angiogenic potential through barrier membranes and confirm that stimulated gingival cells indirectly promote hMSC recruitment, indicating that bone substitute effects extend beyond bone regeneration to include soft tissue healing and inter-tissue communication.

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