Biodegradation pattern and tissue integration of native and cross-linked porcine collagen soft tissue augmentation matrices – an experimental study in the rat

Abstract

IntroductionWithin the last decades, collagen types I and III have been established as a sufficient biomaterial for GBR and GTR procedures. They might also be an adequate matrix for soft tissue augmentations. However, collagen materials differ significantly regarding resorption time, biodegradation pattern and the invasion of inflammatory cells.The aim of the present study was to compare the biodegradation and tissue integration of native, differently processed and cross-linked collagen scaffolds in rats.MethodsFour experimental porcine collagen matrices of 1.0 mm thickness, developed for soft tissue augmentation procedures, were tested. Based on the same native dermal Type I and III collagen, native (ND, Mucoderm® prototype), specifically defatted (DD), ethylene dioxide cross-linked (ECL) and dehydrothermally cross-linked (DCL) dermis collagen (AAP/Botiss Biomaterials, Berlin, Germany) were evaluated. Two specimens of 1 × 1 cm were fixed around a non-absorbable spacer using non-absorbable sutures. After rehydration, specimens (N = 8) were randomly allocated in unconnected subcutaneous pouches on the back of 40 Wistar rats. Rats were divided into five groups (1, 2, 4, 8 and 12 weeks), including eight animals each. After each period, eight rats were sacrificed and explanted specimens were prepared for histological analysis. The following parameters were evaluated: membrane thickness as a sign of biodegradation and volume stability, cell ingrowth, vascularization, tissue integration and foreign body reaction.ResultsBiodegradation pattern of the non cross-linked collagen scaffolds differed only slightly in terms of presence of inflammatory cells and cell invasion into the matrix. In terms of biodegradation, ECL displayed a considerable slower resorption than ND, DCL and DD. Chemical cross-linking using ethylene dioxide showed a significant higher invasion of inflammatory cells.ConclusionWithin the limits of the present study it was concluded that the processing techniques influenced the collagen properties in a different intensity. Dehydrothermal cross-linking and special defatting did not notably change the biodegradation pattern, whereas cross-linking using ethylene dioxide led to significant higher volume stability of the matrix. However, ECL showed an increased inflammatory response and compromised tissue integration. Therefore, ethylene dioxide seems to be not suitable for stabilization of collagen matrices for soft tissue augmentation procedures.

Changes of the peri-implant soft tissue thickness after grafting with a collagen matrix

“…In an animal model, the rough and porous collagen structure was shown to serve as a scaffold for ingrowing blood vessels and cells, enabling revascularization of the matrix and its integration into the surrounding tissue with progressive complete remodeling. [91011] This property may explain the good integration, demonstrated by histological findings, observed in this study. Biopsy samples from all sites showed evidence of angiogenesis and mature connective tissue covered by keratinized epithelium, with clinical gains in mucosal thickness ranging from 0.7 to 1.5 mm.…”

Sequential healing of onlay bone grafts using combining biomaterials with cross‐linked collagen in dogs

“…However, Rothamel et al found no difference in degradation pattern between using NCCM and CCM after 12 weeks in a subcutaneous model (Rothamel et al 2014). Those authors reported that the faster degradation of thermally produced CCM might result from combining collagen types I and III in a porous structure.…”

“…Chemically produced CCM showed improved mechanical properties, but it induced severe inflammatory reactions. Another recent study found that dehydrothermally produced CCM showed comparable biodegradation pattern without inducing a foreign-body reaction (Rothamel et al 2014). …”

Use of Collagen Matrix for Augmentation of the Peri-implant Soft Tissue at the Time of Immediate Implant Placement

“…[21][22][23][24][25] Clinical studies have proven that tissue integration is satisfactory and unproblematic, with complete CM remodeling and biodegradation. 8,9 These promising results can be confirmed by the functional and esthetic outcomes observed in this study.…”