Properties of three collagen scaffolds in comparison with native connective tissue: an in-vitro study

Abstract

Purpose To evaluate collagen scaffolds (CS) in terms of their in vitro resorption behavior, surface structure, swelling behavior, and mechanical properties in physiologically simulated environments, compared with porcine native connective tissue. Materials and methods Three test materials—one porcine collagen matrix (p-CM), two acellular dermal matrices (porcine = p-ADM, allogenic = a-ADM)—and porcine native connective tissue (p-CTG) as a control material were examined for resorption in four solutions using a high-precision scale. The solutions were artificial saliva (AS) and simulated body fluid (SBF), both with and without collagenase (0.5 U/ml at 37 °C). In addition, the surface structures of CS were analyzed using a scanning electron microscope (SEM) before and after exposure to AS or SBF. The swelling behavior of CS was evaluated by measuring volume change and liquid absorption capacity in phosphate-buffered saline (PBS). Finally, the mechanical properties of CS and p-CTG were investigated using cyclic compression testing in PBS. Results Solutions containing collagenase demonstrated high resorption rates with significant differences (p < 0.04) between the tested materials after 4 h, 8 h and 24 h, ranging from 54.1 to 100% after 24 h. SEM images revealed cross-linked collagen structures in all untreated specimens. Unlike a-ADM, the scaffolds of p-CM and p-ADM displayed a flake-like structure. The swelling ratio and fluid absorption capacity per area ranged from 13.4 to 25.5% among the test materials and showed following pattern: p-CM > a-ADM > p-ADM. P-CM exhibited higher elastic properties than p-ADM, whereas a-ADM, like p-CTG, were barely compressible and lost structural integrity under increasing pressure. Conclusions and clinical implications Collagen scaffolds vary significantly in their physical properties, such as resorption and swelling behavior and elastic properties, depending on their microstructure and composition. When clinically applied, these differences should be taken into consideration to achieve the desired outcomes. Graphical Abstract

Influence of an allogenic collagen scaffold on implant sites with thin supracrestal tissue height: a randomized clinical trial

“…An essential consideration in the discourse on effective tissue thickening is the quality of the applied matrix material. In a recent in-vitro trial, the authors observed a low swelling behavior of the allogenic acellular dermal matrix (ADM) used herein, in comparison to a xenogeneic collagen matrix (CM) [ 30 ]. This difference was attributed, in part, to the CM’s sponge-like, multilayered structure as opposed to the more compact structure of an ADM.…”

“…Intriguingly, the native control material also demonstrated minimal compressibility and an inability to sustain its structural integrity. This observation could imply that the allogenic ADM structurally resembles the native material most closely [ 30 ]. In addition to soft tissue considerations, various factors such as implant surface characteristics and the design and type of implant connection seem to play a role in influencing peri-implant hard tissue stability.…”