Test in canine extraction site preservations by using mineralized collagen plug with or without membrane

Bilayer scaffolds/membranes for bone tissue engineering applications: A systematic review

OBJECTIVE

This systematic review evaluates the purpose, materials, physio-mechanical, and biological effects of bilayer scaffolds/membranes used for bone tissue engineering applications.

METHODS

A comprehensive electronic search of English-language literature from 2012 to October 2022 was conducted in PubMed, Scopus, ScienceDirect, and Google Scholar online databases according to the PRISMA 2020 guidelines. The quality of animal studies was evaluated through the SYRCLE's risk of bias tool.

RESULTS

A total of 77 studies were sought for retrieval, and 39 studies met the inclusion criteria. According to the synthesis results, most bilayers had a dense barrier layer that prevented connective tissue penetration and a loose osteogenic layer that supported cell migration and osteogenesis. PLGA, PCL, and chitosan were the most common polymers in the barrier layers, while the most utilized polymers in osteogenic layers were PLGA and gelatin. Electrospinning and solvent casting were the most common fabrication methods to design the bilayer structures. Many studies reported higher biological results for bilayers compared to their single layers. Also, fabricated bilayers' in vitro osteogenesis and in vivo new bone formation were significantly superior or at least comparable to the frequently used commercial membranes.

CONCLUSION

1) Bilayers with two distinct layers and different materials, porosities, mechanical properties, and biological behavior can significantly improve heterogeneous bone regeneration; 2) the addition of ceramics and/or drugs to the osteogenic layer enhances the osteogenic properties of the bilayers; 3) fabrication method and pore size of the layers play an important role in determining the mechanical and biological behavior of them.

Use of Injectable Platelet-Rich Fibrin Accompanied by Bone Graft in Socket Endurance: A Radiographic and Histological Study

Background Ridge preservation became a crucial dental health issue and strategy to keep away from ridge defacement after post-tooth loss. The recent scientific evolution of platelet-rich fibrin (PRF) comprises a parenteral formulation of PRF. The combined allograft for socket preservation gives benefits. In this study, bone allografts, demineralized freeze-dried bone allografts (DFDBA) and freeze-dried bone allografts (FDBA) are used in a 30:70 ratio alone or in combination with injectable PRF (I-PRF) for socket preservation. Methods This study is a radiographic and histological examination conducted on 60 participants aged between 19-65 years. Participating patients agreed voluntarily that they would not bear any fixed prosthesis for the next nine months and plan for implanted teeth placement, including multi-rooted mandibular molars denticles. Both groups received atraumatic extraction; then, the socket was preserved with bone allograft alone in the control group and bone allograft mixed with I-PRF, forming sticky bone, in the experimental group. Clinical, radiological, and histological assessments were taken at the inception stage, three months, six months, and nine months. A multivariate regression model and a generalized estimating equation (GEE) model were used to analyse the effects of these changes on outcomes. Results In all the parameters, the test group indicated a good amount of bone growth with increasing intervals of time for bone height radiographically with statistically significant difference present (p<0.05) and histologically after nine months when socket site grafted with bone graft in combination with I-PRF. Conclusion This study's results demonstrated that I-PRF possesses the potential to regenerate and heal in the tooth-extracted socket. This study further recommends the implementation of I-PRF in safeguarding and conserving the raised rim of the tooth. Future research should take place on the osteogenic capability of I-PRF in more comprehensive ridge accession surgical procedures and additional expanding and improving capacities in periodontal reconstruction.

Collagen Versus Xenograft Bovine Bone Inserted Into Extraction Sockets: Healing and Pain Management

Background

Different materials can be used in filling the extraction socket to achieve an alveolar ridge preservation. The present study compared the wound healing potential and pain management efficacy of the collagen and the xenograft bovine bone, covered by a cellulose mesh, inserted into the socket of extracted teeth.

Materials and Methods

Thirteen patients were willingly chosen to enter our split-mouth study. It was a clinical trial of crossover design with a minimum of two teeth to be extracted for each patient. Randomly, one of the alveolar sockets was filled with collagen material as Collaplug®, and the second alveolar socket was filled with xenograft bovine bone substitute Bio-Oss® and covered with a cellulose mesh Surgicel®. Post-extraction follow-up was observed at day 3, 7 and 14, and each participant was told to document his/her pain experience in our prepared Numerical Rating Scale (NRS) document for 7 consecutive days.

Results

Clinically, the differential wound closure potential between the two groups was significant in the buccolingual (P = 0.045) but not significant in the mesiodistal (P = 0.204) mouth areas. The pain expressed as rated in the NRS was higher in the case of the Bio-Oss®, but there was no significant difference upon comparing the two procedures for 7 consecutive days (P = 0.397) except on day 5 (P = 0.004).

Conclusions

Collagen appears to support faster wound healing rate, higher potential influence on socket healing and decreased pain perception than xenograft bovine bone.

Hierarchical Intrafibrillarly Mineralized Collagen Membrane Promotes Guided Bone Regeneration and Regulates M2 Macrophage Polarization

Mineralized collagen has been introduced as a promising barrier membrane material for guided bone regeneration (GBR) due to its biomimetic nanostructure. Immune interaction between materials and host significantly influences the outcome of GBR. However, current barrier membranes are insufficient for clinical application due to limited mechanical or osteoimmunomodulatory properties. In this study, we fabricated hierarchical intrafibrillarly mineralized collagen (HIMC) membrane, comparing with collagen (COL) and extrafibrillarly mineralized collagen (EMC) membranes, HIMC membrane exhibited preferable physicochemical properties by mimicking the nanostructure of natural bone. Bone marrow mesenchymal stem cells (BMSCs) seeded on HIMC membrane showed superior proliferation, adhesion, and osteogenic differentiation capacity. HIMC membrane induced CD206+Arg-1+ M2 macrophage polarization, which in turn promoted more BMSCs migration. In rat skull defects, HIMC membrane promoted the regeneration of new bone with more bone mass and more mature bone architecture. The expression levels of Runx2 and osterix and CD68 + CD206 + M2 macrophage polarization were significantly enhanced. HIMC membrane provides an appropriate osteoimmune microenvironment to promote GBR and represents a promising material for further clinical application.

In vitro and in vivo study on the osseointegration of magnesium and strontium ion with two different proportions of mineralized collagen and its mechanism

To explore the optimal combination of Mg²⁺, Sr²⁺ and mineralized collagen (nHAC) with two different proportions of hydroxyapatite (HA) and collagen (COL) on differentiation of MC3T3-E1 and the underlying mechanism, as well as achieve bone osseointegration. MC3T3-E1 cells were cultured in a complete medium with Mg²⁺ at the concentration of 0, 4, 8, 12, 16, 20 mmol/L, Sr²⁺ at the concentration of 0, 3, 6, 12 mmol/L, and the impregnation solution of 3:7 and 5:5nHAC. The differentiation of MC3T3-E1 was measured by expression of osteogenic genes and proteins including Runx-2, BMP-2 and OCN and determined the activation of PI3K/AKT/GSK3β/β-catenin signaling pathway in 12 mmol/LMg²⁺+3 mmol/LSr²⁺+3:7nHAC group. Osteoporosis was induced in 18 female rats by means of ovariectomy, the implants were immersed in 60 mmol/LMg²⁺+15 mmol/LSr²⁺+3:7nHAC impregnation solution and implanted into the mesial alveolar fossa for immediate implantation. The osseointegration of the implants was observed by Confocal laser scanning microscopy (CLSM) and histology at 4 and 8 weeks. The groups cultured with 12 mmol/LMg²⁺, 3 mmol/LSr²⁺ and 3:7nHAC impregnation solution showed the osteogenic genes and proteins were significantly higher respectively (P < 0.05), as well as p-Akt, p-GSK3β and β-catenin proteins (P < 0.05). CLSM and histology showed that the implant surface was surrounded by thick lamellar bone plate, and the trabecular bone were dense and continuous in the impregnation solution. These results found that magnesium and strontium ion-loaded mineralized collagen play an critical role in up-regulating the cells activity through PI3K/AKT/GSK3β/β-catenin signaling pathway and could be promote the formation of osseointegration.

[Efficacy of two barrier membranes and deproteinized bovine bone mineral on bone regeneration in extraction sockets: A microcomputed tomographic study in dogs]

OBJECTIVE

To evaluate the effect of two barrier membranes [multilaminated small intestinal submucosa (mSIS) and bioresorable collagen membrane (Bio-Gide)] combined with deproteinized bovine bone mineral Bio-Oss on guided bone regeneration through a canine extraction sockets model.

METHODS

The distal roots of 18 premolars of the Beagle' s bilateral maxillary and mandibular were removed, and 18 extraction sockets were obtained. They were randomly divided into 3 groups, and the following procedures were performed on the sockets: (1) filled with Bio-Oss and covered by mSIS (mSIS group), (2) filled with Bio-Oss and covered by Bio-Gide (BG group), (3) natural healing (blank control group). Micro-computed tomograph (Micro-CT) was performed 4 and 12 weeks after surgery to eva-luate the new bone regeneration in the sockets of each group.

RESULTS

The postoperative healing was uneventful in all the animals, and no complications were observed through the whole study period. Micro-CT analysis showed that the new bone fraction in the mSIS group and the BG group was significantly higher than that in the blank control group at the end of 4 weeks and 12 weeks (P < 0.05), and more new bone fraction was observed in the mSIS group than in the BG group, but the difference was not statistically significant (P>0.05). The new bone fraction of coronal third part of the socket in the mSIS group and BG group at the end of 4 weeks were significantly higher than that of the middle and apical third part of each group (P < 0.05). The values of bone mineral density were similar at 4 weeks in all the groups (P>0.05), but were significantly higher than that in the control group at the end of 12 weeks (P < 0.05). The bone morphometric analysis showed that the trabecular number and trabecular spacing were significantly better in the mSIS group and the BG group than in the control group at the end of 4 weeks and 12 weeks (P < 0.05), while the value in the mSIS group was slightly higher than in the BG group, but the difference was not statistically significant (P>0.05). The difference in trabecular thickness between all the groups was not statistically significant (P>0.05).

CONCLUSION

mSIS membrane as a barrier membrane combined with deproteinized bovine bone mineral can enhance new bone formation in canine extraction sockets, similar to Bio-Gide collagen membrane.

Extraction socket preservation using a collagen plug combined with platelet-rich plasma (PRP): A comparative clinico-radiographic study

Background. Alveolar bone remodeling after tooth loss results in reduced ridge dimensions in horizontal and vertical planes. To prevent this, various authors have proposed different ridge preservation techniques. A collagen plug is a novel material that has shown promising results in preserving the alveolar bone. PRP has also yielded favorable outcomes in wound healing and promoted osteoinduction and osteoconduction Methods. Thirty patients of both sexes with an age range of 30-18 years requiring bilateral extraction of teeth with similar tooth root anatomy in the maxilla or mandible were included in the study. The extraction of teeth was carried out atraumatically. The patients' arches were randomly divided and labeled as the test or control sides. Bone width was measured on both sides. A collagen plug, with PRP, was placed, and the extraction socket was sutured on the test side. The control side was just sutured. A baseline RVG was taken to record the apico-coronal height. The patients were recalled after 10 days for suture removal and evaluation of wound healing. Parameters were re-evaluated at three and six months postoperatively. The data were subjected to t-test and one-way ANOVA. Results. The height of the crestal bone on the grafted side was more when compared to the non-grafted side three and six months after tooth extractions, and the difference was statically significant (P<0.001). No statistically significant difference was seen in the width of the alveolar bone three and six months after tooth extraction (P>0.05). Conclusion. Collagen and PRP provided reasonable socket preservation as simple and inexpensive options as compared to other materials.

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.

Mineralized collagen-modified PMMA cement enhances bone integration and reduces fibrous encapsulation in the treatment of lumbar degenerative disc disease

As a minimally invasive surgery, percutaneous cement discoplasty (PCD) is now contemplated to treat lumbar disc degeneration disease in elder population. Here, we investigated whether the osteogenic mineralized collagen (MC) modified polymethylmethacrylate (PMMA) cement could be a suitable material in PCD surgery. Injectability, hydrophilicity and mechanical properties of the MC-modified PMMA (PMMA-MC) was characterized. The introduction of MC did not change the application and setting time of PMMA and was easy to be handled in minimally invasive operation. Hydrophilicity of PMMA-MC was greatly improved and its elastic modulus was tailored to complement mechanical performance of bone under dynamic stress. Then, PCD surgery in a goat model with induced disc degeneration was performed with implantation of PMMA-MC or PMMA. Three months after implantation, micro-computed tomography analysis revealed a 36.4% higher circumferential contact index between PMMA-MC and bone, as compared to PMMA alone. Histological staining confirmed that the surface of PMMA-MC was in direct contact with new bone, while the PMMA was covered by fibrous tissue. The observed gathering of macrophages around the implant was suspected to be the cause of fibrous encapsulation. Therefore, the interactions of PMMA and PMMA-MC with macrophages were investigated in vitro. We discovered that the addition of MC could hinder the proliferation and fusion of the macrophages. Moreover, expressions of fibroblast-stimulating growth factors, insulin-like growth factor, basic fibroblast growth factor and tumor necrosis factor-β were significantly down-regulated in the macrophages cocultured with PMMA-MC. Together, the promoted osteointegration and reduced fibrous tissue formation observed with PMMA-MC material makes it a promising candidate for PCD surgery.

Mineralized collagen/Mg-Ca alloy combined scaffolds with improved biocompatibility for enhanced bone response following tooth extraction

Mineralized collagen has been used clinically as a bone grafting material in oral applications. We have developed a mineralized collagen/Mg-Ca alloy combined scaffold to overcome the mechanical limitations of mineralized collagen. This study discusses the cytocompatibility of the mineralized collage/Mg-Ca alloy combined scaffold in vitro and the bone regeneration following tooth extraction in vivo. Using an indirect proliferation assay adapted from ISO 10993-5, it was found that mineralized collagen/Mg-Ca alloy combined scaffold enhanced cell proliferation and migration in addition to MC3T3-E1 cells not showing a cytotoxicity response in vitro. Finally, the ability of the combined scaffold to enhance osteogenesis was assessed in a canine socket preservation model. Cone beam CT, x-ray microscopes and biomechanical analysis showed the mineralized collagen/Mg-Ca alloy combined scaffold to be more effective at reducing the absorption of alveolar ridge and preserving the socket site than mineralized collagen alone. The combined scaffolds can promote bone regeneration with good biocompatibility, providing a new concept of the combined application of mineralized collagen and magnesium alloy.