2D and 3D pore structure characterization of bi-layered porous polyethylene barrier membrane using SEM and micro-CT

Abstract

Barrier membrane is an essential component in guided bone regeneration for successful bone augmentation in implant dentistry. The microstructure of barrier membrane can remarkably impact its mechanical properties and biological performances. This study was aimed to investigate the pore structures of a bi-layered porous polyethylene (PPE) barrier membrane by 2D and 3D characterization techniques. Two opposite sides of PPE barrier membrane were imaged with scanning electron microscope and micro-computed tomography (micro-CT). The 2D and 3D pore characteristics were then analysed with associated software, respectively. Both techniques similarly showed that PPE barrier membrane comprised two different structures including one with low porosity (smooth) and one with high porosity (coarse) as designed. In 2D analysis, both surfaces possessed similar positively skewed distributions in pore area and circle diameter. The smooth side had significantly smaller pore amount, pore density, surface porosity, pore area, circle diameter, Feret diameter and aspect ratio, but larger roundness, circularity and solidity than the coarse side (p < 0.05). In 3D analysis, the smooth side possessed significantly smaller pore diameter and volume porosity than the coarse one (p < 0.05). No significant differences in strut thickness, specific surface area, connectivity density (Conn.D), and degree of anisotropy (DA) were found between two layers (p > 0.05). The combination of 2D and 3D techniques could be effectively employed to characterize the pore microstructure and morphology of PPE barrier membrane. The limitations of each technique were also discussed.

Effectiveness of bilayer porous polyethylene membrane for alveolar ridge preservation: A randomized controlled trial

“…Alternative materials are continuing to be developed to improve their properties at a lower cost. Novel B‐PPM used in this study contained two layers with different pore sizes and porosity which were suitable for both rapid fibrovascularization and facilitated new bone formation 12,13,15,35 …”

“…B‐PPM was prepared as described previously 15 . One side of the membrane contained higher porosity with the pore sizes ranging from 140 to 830 mm to facilitate osteoblast proliferation while the other side was designed with less porosity and lower pore size to prevent epithelial cell penetration (Figure 2).…”

Clinical and histological evaluations of alveolar ridge augmentation using a novel bi-layered porous polyethylene barrier membrane

“…From the clinical perspective, in this study, the tight soft tissue adhesion and attachment to PPE membrane observed at re-entry indicate its good biocompatibility and tissue integration that in turn enhance postoperative membrane stability. This feature may be attributed to the specific 2D and 3D pore microstructures characterized previously [22]. These pores not only facilitate transmembrane transport of blood supply, nutrients, oxygen, and thus bone regeneration, but also enable cell occlusiveness.…”

“…The PPE membrane was prepared as described previously [21,22]. Briefly, the mixture of high-density polyethylene (Thaizex 7000F, Bangkok Polyethylene Co., Ltd., Bangkok, Thailand), maltodextrin (Shandong Duqing, Inc., Heze, P. R. China), and polyvinyl alcohol (Sigma-Aldrich Inc., Natick, MA, USA), was prepared at a ratio of 70:20:10 w/w.…”

“…Based on these studies, a new bi-layered porous polyethylene (PPE) that contained both low-and high-porosity layers in a single sheet was developed using a wet salt bed technique, as reported [21]. Its pore microstructure, material properties, and preclinical performance were already characterized [22]. It was postulated that PPE could be utilized as a barrier membrane in GBR procedure for ridge augmentation.…”