The efficacy of a semi-resorbable membrane based on silk fibroin-Glycerol on bone regeneration in rabbit calvarial defects compared to a commercial collagen membrane.

Silk fibroin-glycerol-based membranes were fabricated and characterized for use as a self-maintaining and non-collapsible semi-resorbable membrane in guided bone regeneration. The study assessed the bone regeneration capacity of silk fibroin-glycerol-based membranes compared to a collagen membrane in 10-mm circular bilateral calvarial defects of 20 male New Zealand white rabbits. The animals were divided into two sets of time frames of 4 and 12 weeks and allocated into four groups (n = 5/group); an empty defect (E), a collagen membrane (Bio-Gide®; BG), a silk fibroin-glycerol-collagen membrane (SGC), and a silk fibroin-glycerol membrane (SG). The bone density (optical density, OD) from the 2D radiographs, tissue reaction from histological sections, new bone volume, and area from micro-CT and the histomorphometry were evaluated. The Mean OD of the E (34.49 ± 14.21%) and BG groups (35.71 ± 9.65%) at 12 weeks were higher than at 4 weeks, but the SGC (39.04 ± 7.94%) and SG (40.96 ± 9.25%) groups were lower at 4 weeks. The new bone volumes at 4 weeks of the SG (24.19 ± 1.35%) and SGC groups (24.19 ± 3.47%) were significantly higher than the BG group (16.93 ± 2.95%) but were not different from the E group (18.39±4.78%). At 12 weeks, the new bone volumes in the SGC (29.09 ± 3.81%), SG (29.11 ± 5.94%), and BG groups (26.26 ± 4.42%) were higher than in the E group (21.63 ± 5.81%) without statistical significance. Histological images in the SGC and SG groups showed slow biodegradation without a foreign body reaction. The new bone area at 4 weeks was lowest in BG (12.95 ± 5.44%), and the others were comparable. At 12 weeks, the new bone area in the E group (23.55±8.69%) was lower than the BG (31.42 ± 6.18%), SG (35.25 ± 13.92%), and SGC groups (36.35 ± 10.23%). Silk fibroin-glycerol-based membranes are semi-resorbable membranes that possess a self-maintaining property, have a barrier function without collapsing, and are successful in facilitating bone regeneration.

In Vitro Biocompatibility of a Novel Semi-Rigid Shell Barrier System: As a New Application for Guided Bone Regeneration.

This study evaluated the in vitro biocompatibility of a novel, semi-rigid shell barrier system for guided bone regeneration (GBR) based on polycaprolactone and biphasic calcium phosphate membranes and consisting of a semi-rigid shell (SR) and two semi-resorbable barrier membranes, i.e., a buffered (BF) and an airdried (AD) membrane. In vitro biocompatibility, cell cytotoxicity, cell proliferation and differentiation were evaluated with osteoblast (MC3T3-E1) and fibroblast (L929) cells compared to the d-PTFE membrane (Cytoplast®, CP). The osteoblasts and fibroblasts were well attached and proliferated on all materials from days 1, 3, and 7 without cell cytotoxicity. All groups showed that osteoblast and fibroblast cell proliferation increased from day 1 to day 14-17 and decreased on day 21. On day 21, the CP membrane presented significantly higher osteoblast cell numbers than the BF membrane and the SR shell (p = 0.000). The CP membrane presented a significantly higher amount of fibroblast cells than the other groups (p = 0.000). The SR shell and the BF membrane demonstrated higher osteoblast cell differentiation markers including ALP activity, osteocalcin, and mineral secretion than the CP and the AD membrane. The semi-rigid shell barrier system demonstrated good in vitro biocompatibility and supported osteogenic cell proliferation and differentiation better than the d-PTFE membrane.

Fabrication and characterization of a semi-rigid shell barrier system made of polycaprolactone and biphasic calcium phosphate: A novel barrier system for bone regeneration.

INTRODUCTION: Nowadays, no barrier membrane serves all purposes of bone augmentation. This study aimed to fabricate a semi-rigid shell barrier system composed of a semi-rigid shell and a covering membrane or a semi-resorbable barrier membrane, based on polycaprolactone (PCL) and biphasic calcium phosphate (BCP) for guided bone regeneration (GBR). MATERIALS AND METHODS: A shell and a covering membrane were fabricated by a solvent casting technique based on PCL (70) and BCP (30). The experimental groups were a semi-rigid shell, an airdried membrane, a buffered membrane, and a commercial d-PTFE as a control. Physico-chemical, mechanical properties, and in vitro biocompatibility with osteoblasts and fibroblasts cells were evaluated in all groups. RESULTS: The fabricated materials had rough surfaces with a homogeneous distribution of BCP particles on one side and a smooth surface on the opposite side. The airdried membrane presented a rougher surface on both top and bottom sides (Sq = 605.45 nm, 556.82 nm) than the semi-rigid shell (310.74 nm, 424.56 nm) and the buffered membrane (277.9 nm, 306.98 nm), respectively. The pore sizes of the airdried membrane (25-40 µm) were larger than the semi-rigid shell (5-40 µm) and the buffered membrane (5-25 µm). The porosities of the airdried and buffered membranes (∼40%) were higher than the semi-rigid shell (∼20%) significantly (p < 0.05). All fabricated materials were hydrophilic, with the lowest water contact angle in the semi-rigid shell (54.7° ± 3.06°), then the airdried (61.15° ± 4.76°), and the buffered (75.74° ± 2.8°) respectively. The semi-rigid shell resisted a higher load on compressive force (18.82 ± 2.72 N) than the d-PTFE membrane (4.23 ± 0.5 N). The tensile stress of the buffered membrane (2.544 ± 0.19 MPa) was not different from the d-PTFE (2.908 ± 0.12 MPa) but was higher than the airdried membrane (1.302 ± 0.13 MPa) significantly (P < 0.05). The airdried membrane had reached 100% swelling ability within 1 h, which was significantly faster than the buffered membrane (12 h) and the semi-rigid shell (7 days), and they were slowly degraded by lysozyme at 6 months (airdried: 24.88% ± 0.96%, buffered: 13.67% ± 0.55%, and semi-rigid: 8.62% ± 0.88%). All fabricated membranes showed no toxicity to osteoblast and fibroblast cells. CONCLUSION: The semi-rigid shell and the covering membranes demonstrated suitable physical and mechanical properties, and biocompatibility, and can be assembled as the novel semi-rigid shell barrier system for bone regeneration.