Physicochemical Characterization And Degradation Products Osteogenic Activity Of Four Collagen Membranes

To date,various researches have been performed on dental implants and related implant surgeries,which enables dental implant prosthodontics as a preferred treatment modality towards missing teeth and edentulous dental arches.It is well established that sufficient bone quantity is the prerequisite for the long-term success of dental implants,thus it is required to augment/enhance the bone quantity for patients with severe bone resorptions.Among the various modalities to augment bone quantity,guided bone regeneration(GBR)is regarded as the “gold standard” for its predictability and scalability,which mainly covers the surgical sites with a barrier membrane to form an enclosed but stabilized region to regenerate alveolar bones.Success of GBR is largely attributed to the barrier membrane which blocks the fibroblasts from invading into GBR sites,and thus guaranteed the therapeutic outcomes of bone regeneration at surgical sites.Based on such theory,scholars have summarized criteria an ideal barrier membrane should fulfill,including space maintenance,biocompatibility,occlusivity,clinical manageability,tissue integration and bioactivity.Thus up until the present,an ideal barrier membrane which fulfill all these criteria,is still under exploration.Initially,the non-absorbable membranes were clinically preferred due to their stability and degradation resistance.However such non-absorbable membranes are always rigid and easy to penetrate the oral mucosa during wound healing,which will expose the GBR region and cause postsurgical inflammation/infection,also the required second-stage surgery to remove such membrane will cause excessive surgical trauma to the patients.While the absorbable membrane does not have such concerns,for its flexible/soft mechanical properties and easily degradation features,and collagen membrane is the most widely applied options.Aim of this study is to compare the therapeutic outcomes of four clinically preferred commercial collagen membranes by evaluating their barrier functions,and bioactivities,to find the optimized collagen membrane for a reliable GBR.The following experiments were performed:Experiment 1 is to compare the physical/chemical properties of four selected collagen membranes,by evaluating their tensile strength,elongation at break and Young's modulus.Furthermore,their hydrophilicities were investigated by a water contact angle(WCA),and surface topographies studied by a field emission scanning electron microscopy(FESEM).Finally,the absorption of such membranes were stimulated by in vitro degradation experiment and their weight loss during degradation were calculated.The results showed that the Lyoplant membrane performed better mechanical property,and the Bio-Gide membrane was more hydrophilic,the Giterui membrane performs better in terms of micro-morphology,including three-dimension network and porous structure,and the Bio-Gide membrane was shown with lowest degradation speed.Experiment 2 aims at comparing the osteogenicity of the degradation products of collagen membranes.The degradation of collagen membranes were mimicked by in vitro degradation experiments,and the total protein quantity of the degradation products was detected by the BCA protein concentration kits.Components of degradation products were detected by SDS-PAGE gel electrophoresis,and the proliferation of MC3T3-E1 cells in degradation products were evaluated by CCK-8 kit.Furthermore,the ALP activity and osteogenesis-related gene mRNA expression levels of MC3T3-E1 cells that cultured in degradation products were evaluated.The results showed a highest total protein residual from Hai'ao membrane after the degradation,and the components of four collagen membranes degradation products were similar with minor deviations.The degradation products of Haiao membrane showed optimized in promoting MC3T3-E1 cell proliferation and differentiation.Generally,all the membranes showed different mechanical property and degradation performances,including excellent mechanical properties of Lyoplant,high hydrophilicity and slow degradation rate of Bio-Gide,optimized microstructure of Giterui,and superior bioactivity of Hai'ao,which is compatible with complex clinical needs.Based on the research data,our recommendations are as follows,for membrane with poor mechanical properties,addition supoort such as bone graft materials,membrane nails and sutrue retention could be given to compensate for their mechanical strength;for clinical cases that require more support from the barrier membrane,such as simultaneous vertical and horizontal bone augmentation Lyoplant membranes with superior mechanical properties can be selected;for cases with bad oral hygiene,high wound tension,and potential membrane exposure,Bio-Gide membranes with strong enzyme resistance can be selected.What's more,for more complex clinical,the double-layer membrane implantation method could be chosen when needed.To place different collagen membranes to the wound side and the defect side could maximize the advantages of different collagen membranes.Lyoplant membrane with excellent mechanical properties or Bio-Gide membrane with higher enzyme-resistance or Gitterui membrane with microscopic morphology benefit for fibroblast adhesion and proliferation could be implant to the woud side,at the same time,the bioactive Hai'ao membrane could be placed on the defect side.