Comparative study of chitosan/fibroin–hydroxyapatite and collagen membranes for guided bone regeneration in rat calvarial defects: micro-computed tomography analysis

This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.

Real-time-guided bone regeneration around standardized critical size calvarial defects using bone marrow-derived mesenchymal stem cells and collagen membrane with and without using tricalcium phosphate: an in vivo microcomputed tomographic and histologic e

The aim of the present real time in vivo micro-computed tomography （pCT） and histologic experiment was to assess the efficacy of guided bone regeneration （GBR） around standardized calvarial critical size defects （CSD） using bone marrow-derived mesenchymal stem cells （BMSCs）, and collagen membrane （CM） with and without tricalcium phosphate （TCP） graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD （diameter 4.6 mm） were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone （NFB） and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo pCT. At the lOth week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness of NFB was similar to that of the native bone in groups I and 2 as compared to the NFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical ＂lock＂ between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adiunct BMSC therapy.

Comparative evaluation of effect of injectable platelet-rich fibrin with collagen membrane compared with collagen membrane alone for gingival recession coverage

BACKGROUND Collagen membrane and platelet-rich fibrin(PRF)have emerged as vital biomaterials in the field of periodontal regeneration.Minimally invasive techniques are being preferred by most periodontists,as it is patient compliant with fewer post-surgical complications as compared to conventional surgical techniques.Thus,in this study we have evaluated the effect of injectable PRF(i-PRF)with collagen membrane compared with collagen membrane alone using vestibular incision subperiosteal tunnel access(VISTA)technique for gingival recession coverage.AIM To compare the efficacy of VISTA using collagen membrane with collagen membrane soaked in injectable PRF for gingival recession coverage.METHODS A split mouth randomized controlled clinical trial was designed;13 subjects having at least 2 teeth indicated for recession coverage were enrolled in this study.The sites were randomly assigned to control group(VISTA using collagen membrane alone)and the test group(VISTA using collagen membrane with i-PRF).The clinical parameters assessed were pocket depth,recession depth(RD),recession width(RW),relative attachment level,keratinised tissue width(KTW),keratinised tissue thickness(KTT),and percentage root coverage.RESULTS RD showed a statistically significant difference between the test group at 3 mo(0.5±0.513)and 6 mo(0.9±0.641)and the control group at 3 mo(0.95±0.51)and 6 mo(1.5±0.571),with P values of 0.008 and 0.04,respectively.RW also showed a statistically significant difference between the test group at 3 mo(1±1.026)and 6 mo(1.65±1.04)and the control group at 3 mo(1.85±0.875)and 6 mo(2.25±0.759),with P values of 0.008 and 0.001,respectively.Results for KTW showed statistically significant results between the test group at 1 mo(2.85±0.489),3 mo(3.5±0.513),and 6 mo(3.4±0.598)and the control group at 1 mo(2.45±0.605),3 mo(2.9±0.447),and 6 mo(2.75±0.444),with P values of 0.04,0.004,and 0.003,respectively.Results for KTT also showed statistically significant results between test group at 1 mo(2.69±0.233),3 mo(2.53±0.212),and 6 mo(2.46±0.252)and the control group at 1 mo(2.12±0.193),3 mo(2.02±0.18),and 6 mo(1.91±0.166),with P values of 0.001,0.001,and 0.001,respectively.The test group showed 91.6%,81.6%,and 67%root coverage at 1 mo,3 mo,and 6 mo,while the control group showed 82.3%,66.4%,and 53.95%of root coverage at 1 mo,3 mo,and 6 mo,respectively.CONCLUSION The use of minimally invasive VISTA technique along with collagen membrane and injectable form of platelet-rich fibrin can be successfully used as a treatment method for multiple or isolated gingival recessions of Miller’s class-I and class-II defects.

Systematic evaluation of three porcine-derived collagen membranes for guided bone regeneration

Guided bone regeneration is one of the most common surgical treatment modalities performed when an additional alveolar bone is required to stabilize dental implants in partially and fully edentulous patients.The addition of a barrier membrane prevents non-osteogenic tissue invasion into the bone cavity,which is key to the success of guided bone regeneration.Barrier membranes can be broadly classified as non-resorbable or resorbable.In contrast to non-resorbable membranes,resorbable barrier membranes do not require a second surgical procedure for membrane removal.Commercially available resorbable barrier membranes are either synthetically manufactured or derived from xenogeneic collagen.Although collagen barrier membranes have become increasingly popular amongst clinicians,largely due to their superior handling qualities compared to other commercially available barrier membranes,there have been no studies to date that have compared commercially available porcine-derived collagen membranes with respect to surface topography,collagen fibril structure,physical barrier property,and immunogenic composition.This study evaluated three commercially available non-crosslinked porcine-derived collagen membranes(Striate+TM,Bio-Gide®and CreosTM Xenoprotect).Scanning electron microscopy revealed similar collagen fibril distribution on both the rough and smooth sides of the membranes as well as the similar diameters of collagen fibrils.However,D-periodicity of the fibrillar collagen is significantly different among the membranes,with Striate+TM membrane having the closest D-periodicity to native collagen I.This suggests that there is less deformation of collagen during manufacturing process.All collagen membranes showed superior barrier property evidenced by blocking 0.2–16.4µm beads passing through the membranes.To examine the immunogenic agents in these membranes,we examined the membranes for the presence of DNA and alpha-gal by immunohistochemistry.No alpha-gal or DNA was detected in any membranes.However,using a more sensitive detection method(real-time polymerase chain reaction),a relatively strong DNA signal was detected in Bio-Gide®membrane,but not Striate+TM and CreosTM Xenoprotect membranes.Our study concluded that these membranes are similar but not identical,probably due to the different ages and sources of porcine tissues,as well as different manufacturing processes.We recommend further studies to understand the clinical implications of these findings.

Collagen membrane alleviates peritendinous adhesion in the rat Achilles tendon injury model

Background Tendon adhesion is one of the most common causes of disability following tendon surgery. Therefore, prevention of peritendinous adhesion after surgical repair of tendon is a major challenge. The aim of this study was to explore the possible application of a collagen membrane for the prevention or attenuation of peritendinous adhesions. Methods Sprague-Dawley （SD） rat Achilles tendon was cut and sutured by a modified Kessler＇s technique with or without the collagen membrane wrapped. Macroscopic, morphological and biomechanical evaluations were applied to examine the recovery of the injured tendon at 4 and 8 weeks after surgery. Results The surgery group wrapped by collagen membranes had a better outcome than the group with surgery repair only. In the collagen membrane-treated group, less adhesion appeared, stronger tensile strength was detected, and more tendon fibers and collagen I expression were observed morphologically. Conclusion Wrapping the tendon with a collagen membrane may be an efficient approach for tendon repair and preventing tendon adhesion after its ruptures.

Porous titanium granules in critical size defects of rabbit tibia with or without membranes

Recently, porous titanium granules （PTGs） have been indicated for the preservation of the dimensions of post-extraction sockets, as a filler in sinus lift procedures and for the treatment of peri-implant and periodontal defects, based on the osteoconductivity and dimensional stability of the titanium granules. However, there is a lack of information regarding the use of this material in larger defects and in conjunction with membranes. The objective of this study is to test the behavior of PTGs used to fill critical size defects in rabbit tibiae, with and without membranes. Critical defects were created in both tibiae of rabbits, divided randomly into three groups： Group A （defect filled with PTG）, Group B （defect filled with PTG＋collagen membrane） and a control group （empty defect）. After six weeks, histomorphometric analysis was performed. The results showed more defect closures at the cortical area （87.37%±2.2%） and more bone formation at the marrow area （57.6%± 1.3%） in Group B, in comparison with the other groups （P〈0.05）; the use of membranes improved the material stability expressed as more percentages of the original material when membranes were used （P〈0.05）. Finally, inflammatory reactions were observed when the granules were not protected by membranes. In spite of the limitations of this animal study, it may be concluded that PTG particles are osteoconductive and allow bone growth. The PTG particles must be covered by a membrane, especially when grafting larger defects, in order to control particle migration, promote clot stabilization and separate the PTG graft from undesired soft tissue cells.

Collagen fiber membrane-derived chemically and mechanically durable superhydrophobic membrane for high- performance emulsion separation

Developing high-performance separation membrane with good durability is a highly desired while challenging issue.Herein,we reported the successful fabrication of chemically and mechanically durable superhydrophobic membrane that was prepared by embedding UiO-66 as size-sieving sites within the supramolecular fiber structure of collagen fiber membrane(CFM),followed by the polydimethylsiloxane(PDMS)coating.The as-prepared CFM/UiO-66(12)/PDMS membrane featured capillary effect-enhanced separation flux and homogeneous porous channels guaranteed high separation efficiency.When utilized as double-layer separation membranes,this new type of composite membranes separated various surfactant stabilized water-in-oil microemulsions and nanoemulsions,with the separation efficiency high up to 99.993%and the flux as high as 973.3 L m−2 h−1.Compared with commercial polytetrafluoro ethylene(PTFE)membrane,the advantage of the double-layer CFM/UiO-66(12)/PDMS membranes in separation flux was evident,which exhibited one order of magnitude higher than that of commercial PTFE membrane.The CFM/UiO-66(12)/PDMS membrane was acid-alkali tolerant,UV-aging resistant and reusable for emulsion separation.Notably,the CFM/UiO-66(12)/PDMS membrane was mechanically durable against strong mechanical abrasion,which was still capable of separating diverse water-in-oil emulsions after the abrasion with sandpaper and assembled as double-layer separation membranes.We anticipate that the combination of CFM and metal organic frameworks(MOFs)is an effective strategy for fabricating high-performance separation membrane with high mechanical and chemical durability.

Study on repairing canine mandibular defect with porous Mg-Sr alloy combined with Mg-Sr alloy membrane

To discuss the feasibility of the application of porous Mg-Sr alloy combined with Mg-Sr alloy membrane in the repair of mandibular defects in dogs.The second and third mandibular premolars on both sides were extracted from six dogs.The model of mandible buccal fenestration bone defects were prepared after the sockets healed.Twelve bone defects were randomly divided into groups A and B,then Mg-Sr alloy was implanted in bone defects of group A and covered by Mg-Sr alloy membrane while Mg-Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane.Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4,8 and 12 weeks.After 12 weeks,the healing of bone defects were evaluated by gross observation,X-ray microscopes and histological observation of hard tissue.Bone defects in each group were repaired.At 8 and 12 weeks,the gray value of group A was higher than that of group B(P<0.05).At 12 weeks,the bone volume fraction of group A was higher than that of group B(P<0.05).The newly woven bone in group A is thick and arranged staggered,which was better than that of group B.Porous Mg-Sr alloy combined with Mg-Sr alloy membrane could further promote the repair of mandibular defects,and obtain good osteogenic effect.