Biodegradable polylactide membranes for bone defect coverage: biocompatibility testing, radiological and histological evaluation in a sheep model

Abstract

Large bony defects often show a delayed healing and have an increasing risk of infection. Several materials are used for the coverage of large defects. These materials must be biocompatible, easy to use, and must have an appropriate stability to present a mechanical hindrance. Aim of this study was to investigate two different biodegradable membranes for defect coverage in a sheep model. Round cranial defects (1.5 cm diameter) were created in sheep. Six different treatments were investigated: defects without membrane, defects covered with a poly(D,L-lactide) or with a 70/30 poly(L/D,L-lactide) membrane and all defects with or without spongiosa filling. The sheep were sacrificed 12 or 24 weeks postoperatively. Bone formation in the defects was quantified by computer-assisted measurements of the area of the residual defect on CT radiographs. Histomorphometry and host-tissue response were evaluated by light microscopy. The biocompatibility was investigated by analyzing the amount of osteoclasts and foreign body cells. Both membranes served as a mechanical hindrance to prevent the prolapse of soft tissue into the defect. The biocompatibility test revealed no differences in the amount and distribution of osteoclasts at the two investigated time points and between the investigated groups. No negative effect on the tissue regeneration was detectable between the investigated groups related to the type of membrane, but a foreign body reaction around the two membrane types was observed. In the membrane-covered defects, the spongiosa showed a progressing remodeling to the native bony structure of the cranium. The groups without spongiosa partly revealed new bone formation, without complete bridging in any group or at any time point. Comparing the 12 and 24 weeks groups, an increased bone formation was detectable at the later time point. In conclusion, the results of the present in vivo study reveal a good biocompatibility and prevention of soft tissue prolapse of the two used membranes without differences between the membranes. An enhanced remodeling of the spongiosa into native bony structures under the membranes was detectable, but no osteopromoting effect was observed due to the membranes.

Bone Regeneration after Treatment with Covering Materials Composed of Flax Fibers and Biodegradable Plastics: A Histological Study in Rats

“…Enhanced remodeling of the spongiosa into native bony under the membranes could be detected in cranial defects but also without an osteopromoting effect. In contrast to our study, a foreign body reaction around the tested membranes was observed in sheep [73]. …”

Nanomaterials for Tissue Engineering In Dentistry

“…These membranes have first been not absorbable [32,158,159] and then adsorbable [33,160,161,162], bringing to two types of clinical application, the Guided Tissue Regeneration (GTR) and the Guided Bone Regeneration (GBR). It is one of the most fertile fields of applied clinical research and the recent introduction of the use of nanomaterials [78,163] has led to further advances: on the one hand, the use of nanopowders [164] but above all the development of periodontal membranes, both for GTR and GBR, obtained by nanotechnological methods such as film-casting [165,166,167], dynamic filtration [168] or electrospinnig [169,170].…”

Electrospun Nanofibrous P(DLLA–CL) Balloons as Calcium Phosphate Cement Filled Containers for Bone Repair: in Vitro and in Vivo Studies

“…However, although systematic comparisons between the in vitro and in vivo behaviors of ENPBs are important before they are evaluated in the clinic, such comparisons were not made in our previous work Polymer materials have been widely used as biomedical materials. [27][28][29][30][31] Many synthetic polymer biomaterials similar to P(DLLA-CL), such as PDLLA, [32][33][34][35] PLGA, 36-37 P(LLA-CL), 38 and PCL, [39][40] have been assessed in vivo to determine their behaviors in the bone microenvironments of sheep, [32][33][35][36] rabbit, 34,37 and pig. [38][39][40] However, there have been no reports evaluating the in vivo behaviors of P(DLLA-CL) biomaterials in bone microenvironments thus far.…”