Current barrier membranes: Titanium mesh and other membranes for guided bone regeneration in dental applications

A 3D micro-CT assessment of composition and structure of bone tissue after vertical and horizontal alveolar ridge augmentation using CAD/CAM-customized titanium mesh

OBJECTIVES

To date, no studies have exploited micro-CT in humans to evaluate bone morphology and structure after bone augmentation with CAD/CAM-customized titanium mesh, in mandible and maxilla. The aim of this study was to assess the composition and microstructure of bone biopsy through micro-CT analysis.

MATERIALS AND METHODS

Bone augmentation at both maxillary and mandible sites was performed on 30 patients randomly treated with customized mesh, either alone (M-) or covered with resorbable membrane (M+), in both cases filled 50:50 with autogenous bone and xenograft. After 6 months, biopsies were taken and micro-CT was performed on consecutive 1-mm-thick VOIs from coronal to apical side, measuring tissue volumes, trabecular thickness, spacing, and number.

RESULTS

In both groups, irrespective of membrane use, bone tissue (M-: 29.76% vs. M+: 30.84%) and residual graft material (M-: 14.87% vs. M+: 13.11%) values were similar. Differences were site-related (maxillary vs. mandibular) with higher percentage of bone tissue and trabecular density of low-mineralized bone and overall bone in the mandible.

CONCLUSIONS

The composition and structure of bone tissue, as assessed by micro-CT after alveolar ridge augmentation using CAD/CAM-customized titanium meshes, showed similar features regardless of whether a collagen membrane was applied.

A novel bi-layered asymmetric membrane incorporating demineralized dentin matrix accelerates tissue healing and bone regeneration in a rat skull defect model

Objectives: The technique of guided bone regeneration (GBR) has been widely used in the field of reconstructive dentistry to address hard tissue deficiency. The objective of this research was to manufacture a novel bi-layered asymmetric membrane that incorporates demineralized dentin matrix (DDM), a bioactive bone replacement derived from dentin, in order to achieve both soft tissue isolation and hard tissue regeneration simultaneously. Methods: DDM particles were harvested from healthy, caries-free permanent teeth. The electrospinning technique was utilized to synthesize bi-layered DDM-loaded PLGA/PLA (DPP) membranes. We analyzed the DPP bilayer membranes' surface topography, physicochemical properties and degradation ability. Rat skull critical size defects (CSDs) were constructed to investigate in vivo bone regeneration. Results: The synthesized DPP bilayer membranes possessed suitable surface characteristics, acceptable mechanical properties, good hydrophilicity, favorable apatite forming ability and suitable degradability. Micro-computed tomography (CT) showed significantly more new bone formation in the rat skull defects implanted with the DPP bilayer membranes. Histological evaluation further revealed that the bone was more mature with denser bone trabeculae. In addition, the DPP bilayer membrane significantly promoted the expression of the OCN matrix protein in vivo. Conclusions: The DPP bilayer membranes exhibited remarkable biological safety and osteogenic activity in vivo and showed potential as a prospective candidate for GBR applications in the future.

Evaluation of platelet-rich fibrin versus collagen membrane for enhancing healing of secondary grafted alveolar cleft: a randomised controlled trial

The purpose of this study was to compare the efficiency of using autologous platelet-rich fibrin versus a resorbable collagen membrane in secondary alveolar bone grafting. Patients were randomly allocated to the three treatment groups: Group 1 - twelve children in whom the nasal layers of the alveolar clefts were repaired using autologous platelet-rich fibrin with autogenous chin bone; Group 2 - twelve children in whom the nasal layers of the alveolar clefts were repaired using bovine collagen membrane type I (Colla-D) with autogenous chin bone; and Group 3 - twelve children in whom the bony alveolar clefts were grafted with autogenous chin bone after construction of a watertight nasal floor had been completed. The study population comprised 36 patients with alveolar clefts, ranging in age from seven to 12 years. At the last follow-up period all groups had stable healing conditions and good radiological outcomes in terms of the alveolar bone height bordering the teeth (both mesially and distally) and the incorporation of grafting material with the surrounding bone. The use of either a PRF membrane and a collagen membrane as an interpositional layer between the nasal layer and the autogenous chin bone graft enhanced bone formation and density in alveolar clefts compared with the control group.

In vivo comparison of customized zirconia barriers in guided bone regeneration: An experimental study

Objective

This study aims to evaluate the effects of customized zirconia barrier membranes produced for guided bone regeneration (GBR) approaches on bone healing researched with histological and histomorphometric methods.

Methods

The digital modeling was used to create zirconia barrier membranes suitable for the defect on the tibia bone. The membranes were designed using a 3D software system and transferred to the CAD/CAM software system in stl. Afterward, zirconia discs (1400 Mpa) (Aconia BSM- D98 × 16, HT+, Germany) were milled and sintered. Titanium mesh, titanium reinforced d-PTFE, and zirconia barrier membranes were used to cover the defects. As a control group, one defect was left empty. 3 and 6 weeks of the healing term, preparates were obtained from each group after animals were sacrificed. New bone formation, amount of the remaining grafts and tissue response parameters were analyzed histomorphometrically and histologically.

Results

The highest percentage of newly formed bone in the early period was observed in the titanium mesh membrane group (26.39 ± 5.38); In the late period, this rate was highest in the zirconia group (64.42 ± 9.95). However, no statistically significant difference was found in both periods between the groups. The amount of residual graft progressed at a low level in both periods without any difference in the other groups except the control group. In the 3rd and 6th weeks, the amount of new bone formation was the lowest in the control group. No foreign body reaction or necrosis was observed in any of the defects.

Conclusion

With the limitation of the study, it has been concluded that effective results can be obtained with customized zirconia barrier membranes in GBR procedures.

Titanium mesh for guided bone regeneration: a systematic review

This systematic review aimed to evaluate results reported in the literature regarding the success rate of the titanium mesh technique for the placement of dental implants. The topic focused on titanium mesh used as a physical barrier for ridge reconstruction in cases of partial or total edentulism. The authors conducted an electronic search of four databases up to October 2023. Six articles fulfilled the inclusion criteria and were analysed. A total of 100 titanium meshes with a minimum of 4.6 months follow up after surgery were studied, and 241 implants were placed. The review shows that the use of titanium mesh is a predictable method for the rehabilitation of complex atrophic sites. Further investigation generating long-term data is needed to confirm these findings.

Functionalizable bacterial cellulose composite membrane for guided tissue regeneration

This research aims to develop guided tissue regeneration (GTR) membranes from bacterial cellulose (BC), a natural polysaccharide-based biopolymer. A double-layered BC composite membrane was prepared by coating the BC membrane with mixed carboxymethyl cellulose/poly(ethylene oxide) (CMC/PEO) fibers via electrospinning. The CMC/PEO-BC membranes were then characterized for their chemical and physical characteristics. The 8 % (wt/v) CMC/PEO (1:1) aqueous solution yielded well-defined electrospun CMC/PEO nanofibers (125 ± 10 nm) without beads. The CMC/PEO-BC membranes exhibited good mechanical and swelling properties as well as good cytocompatibility against human periodontal ligament cells (hPDLs). Its functionalizability via carboxyl entities in CMC was tested using the calcium-binding domain of plant-derived recombinant human osteopontin (p-rhOPN-C122). As evaluated by enzyme-linked immunosorbent assay, a 98-99 % immobilization efficiency was achieved in a concentration-dependent manner over an applied p-rhOPN-C122 concentration range of 7.5-30 ng/mL. The biological function of the membrane was assessed by determining the expression levels of osteogenic-related gene transcripts using quantitative real-time reverse-transcriptase polymerase chain reaction. Mineralization assay indicated that the p-rhOPN-C122 immobilized CMC/PEO-BC membrane promoted hPDLs osteogenic differentiation. These results suggested that the developed membrane could serve as a promising GTR membrane for application in bone tissue regeneration.

Macrophages in guided bone regeneration: potential roles and future directions

Guided bone regeneration (GBR) is one of the most widely used and thoroughly documented alveolar bone augmentation surgeries. However, implanting GBR membranes inevitably triggers an immune response, which can lead to inflammation and failure of bone augmentation. It has been shown that GBR membranes may significantly improve in vivo outcomes as potent immunomodulators, rather than solely serving as traditional barriers. Macrophages play crucial roles in immune responses and participate in the entire process of bone injury repair. The significant diversity and high plasticity of macrophages complicate our understanding of the immunomodulatory mechanisms underlying GBR. This review provides a comprehensive summary of recent findings on the potential role of macrophages in GBR for bone defects in situ. Specifically, macrophages can promote osteogenesis or fibrous tissue formation in bone defects and degradation or fibrous encapsulation of membranes. Moreover, GBR membranes can influence the recruitment and polarization of macrophages. Therefore, immunomodulating GBR membranes are primarily developed by improving macrophage recruitment and aggregation as well as regulating macrophage polarization. However, certain challenges remain to be addressed in the future. For example, developing more rational and sophisticated sequential delivery systems for macrophage activation reagents; addressing the interference of bone graft materials and dental implants; and understanding the correlations among membrane degradation, macrophage responses, and bone regeneration.

Long-Term Volumetric Stability of Maxillary Sinus Floor Augmentation Using a Xenograft Bone Substitute and Its Combination with Autologous Bone: A 6+ Year Retrospective Follow-Up Study Using Cone Beam Computed Tomography

Deproteinised bovine bone (DBB) is widely used as bone substitute in maxillary sinus floor augmentation (MSFA) surgery. No previous studies have shown the long-term volumetric changes in the augmented bone when using DBB. The selected patients had MFSA performed using a lateral window technique and a xenograft, alone or in combination with the patient's autologous bone from the mandible. Cone beam computed tomography (CBCT) images were used to compare the volumetric changes in the augmented bone for patients over a period of 6 or more years. No significant bone reduction was seen in the augmented bone region when comparing MSFA after 7 months and 6 or more years after dental implantation.

Advances in guided bone regeneration membranes: a comprehensive review of materials and techniques

Guided tissue/bone regeneration (GTR/GBR) is a widely used technique in dentistry to facilitate the regeneration of damaged bone and tissue, which involves guiding materials that eventually degrade, allowing newly created tissue to take its place. This comprehensive review the evolution of biomaterials for guided bone regeneration that showcases a progressive shift from non-resorbable to highly biocompatible and bioactive materials, allowing for more effective and predictable bone regeneration. The evolution of biomaterials for guided bone regeneration GTR/GBR has marked a significant progression in regenerative dentistry and maxillofacial surgery. Biomaterials used in GBR have evolved over time to enhance biocompatibility, bioactivity, and efficacy in promoting bone growth and integration. This review also probes into several promising fabrication techniques like electrospinning and latest 3D printing fabrication techniques, which have shown potential in enhancing tissue and bone regeneration processes. Further, the challenges and future direction of GTR/GBR are explored and discussed.

Semi-customized three-dimensional ultra-fine titanium meshes in guided bone regeneration for implant therapy in severe alveolar bone defect: a case report

This case report provides a detailed description of a simple and fast bone regeneration procedure using a semi-customized three-dimensional ultra-fine titanium mesh. A 50-year-old male with a severe vertical and horizontal bone defect in the anterior mandible underwent implant treatment in a staged approach. The autologous bone was combined with a xenograft, and the mixture was grafted to augment the bone defect and covered with semi-customized ultra-fine titanium meshes, which were selected among its various types according to size and configuration of the bone defect, directly connected and immobilized on the tenting screws with minimal shaping. In a postoperative 6 months re-entry surgery, the performed titanium meshes were removed, implants were placed, and a bone core biopsy was obtained that demonstrated satisfactory new bone formation. Finally, two months later, the definitive prosthesis was installed. This semi-customized ultra-fine titanium mesh could help an implant clinician obtain more predictable results in the guided bone regeneration (GBR).

Green synthetic sodium alginate-glycerol-MXene nanocomposite membrane with excellent flexibility and mineralization ability for guided bone regeneration

Developing a novel bioactive material as a barrier membrane for guided bone regeneration (GBR) surgery remains challenging. As a new member of two-dimensional (2D) material family, MXene is a promising candidate component for barrier membranes due to its high specific surface area and osteogenic differentiation ability. In this work, a green and simple SA/glycerol/MXene (SgM) composite membrane was prepared via solvent casting method by using sodium alginate (SA) and MXene (M) as raw materials while employing glycerol (g) as a plasticizer. The addition of glycerol significantly increased the elongation at the break of SA from 10%-20% to 240%-360%, while the introduction of MXene promoted the deposition of calcium and phosphorus to form hydroxyapatite. At the same time, the roughness of the SgM composite membrane is apparently improved, which is conducive to cell adhesion and proliferation. This work provides a basis for further research on SgM composite membrane as GBR membrane for the treatment of bone defects.

Critical-size defects reconstruction with four different bone grafts associated with e-PTFE membrane: A histomorphometric experimental in vivo study

OBJECTIVES

The goal of this study was to assess the newly formed bone and the remnant biomaterial by comparing four different bone grafts used to treat critical-size defects, associated or not with the non-resorbable membrane.

MATERIALS AND METHODS

Two calvaria critical-size bone defects were created in 50 male Wistar rats. They were divided into blood (G1), autogenous (G2), bioglass (G3), hydroxyapatite (G4), and xenograft (G5) groups, associated or not with e-PTFE. The experimental periods were 15 and 45 days. Sections were prepared for histomorphometric assessment. All data were analyzed by the mixed-effects model with multiple comparisons (significance level, p < .05).

RESULTS

A similar level of new bone was observed for all groups, associated with a high level of vascularization. G1 and G2 ensured sovereignty over the greater quantity of new bone. A non-significant result was reported comparing groups with and without membranes. No significant result was found between the experimental synthetic biomaterials (G3 and G4). G5L achieved 22.0% of new bone after 45 days (p > .05). All groups had a stable volume of biomaterial kept in the short term (p > .05). G2 was the best material for new bone formation and final volume of biomaterial, followed by G4 < G5 < G3. Thus, it is possible that G4 had a better degradation profile among the experimental groups.

CONCLUSIONS

The best results were found in the autogenous group, with higher resorption and integration; non-significative new bone was found among the experimental groups; and the regeneration of critical bone defects using an e-PTFE barrier did not present significant results on new bone formation.

Guided bone regeneration of calcium phosphate-coated and strontium ranelate-doped titanium mesh in a rat calvarial defect model

PURPOSE

When applied alone, titanium (Ti) mesh may not effectively block the penetration of soft tissues, resulting in insufficient new bone formation. This study aimed to confer bioactivity and improve bone regeneration by doping calcium phosphate (CaP) precipitation and strontium (Sr) ranelate onto a TiO2 nanotube (TNT) layer on the surface of a Ti mesh.

METHODS

The TNT layer was obtained by anodizing on the Ti mesh, and CaP was formed by cyclic pre-calcification. The final specimens were produced by doping with Sr ranelate. The surface properties of the modified Ti mesh were investigated using high-resolution field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. To evaluate the effects of surface treatment on cell viability, osteoblasts were cultured for 1-3 days, and their absorbance was subsequently measured. In an in vivo experiment, critical-size defects were created in rat calvaria (Ф=8 mm). After 5 weeks, the rats were sacrificed (n=4 per group) and bone blocks were taken for micro-computed tomography and histological analysis.

RESULTS

After immersing the Sr ranelate-doped Ti mesh in simulated body fluid, the protrusions observed in the initial stage of hydroxyapatite were precipitated as a dense structure. On day 3 of osteoblast culture, cell viability was significantly higher on the pre-calcified Sr ranelate-doped Ti mesh surface than on the untreated Ti mesh surface (P<0.05). In the in vivo experiment, a bony bridge formed between the surrounding basal bone and the new bone under the Sr ranelate-doped Ti mesh implanted in a rat calvarial defect, closing the defect. New bone mineral density (0.91±0.003 g/mm3) and bone volume (29.35±2.082 mm3) significantly increased compared to the other groups (P<0.05).

CONCLUSIONS

Cyclic pre-calcification of a Ti mesh with a uniform TNT layer increased bioactivity, and subsequent doping with Sr ranelate effectively improved bone regeneration in bone defects.

All-in-one porous membrane enables full protection in guided bone regeneration

The sophisticated hierarchical structure that precisely combines contradictory mechanical and biological characteristics is ideal for biomaterials, but it is challenging to achieve. Herein, we engineer a spatiotemporally hierarchical guided bone regeneration (GBR) membrane by rational bilayer integration of densely porous N-halamine functionalized bacterial cellulose nanonetwork facing the gingiva and loosely porous chitosan-hydroxyapatite composite micronetwork facing the alveolar bone. Our GBR membrane asymmetrically combine stiffness and flexibility, ingrowth barrier and ingrowth guiding, as well as anti-bacteria and cell-activation. The dense layer has a mechanically matched space maintenance capacity toward gingiva, continuously blocks fibroblasts, and prevents bacterial invasion with multiple mechanisms including release-killing, contact-killing, anti-adhesion, and nanopore-blocking; the loose layer is ultra-soft to conformally cover bone surfaces and defect cavity edges, enables ingrowth of osteogenesis-associated cells, and creates a favorable osteogenic microenvironment. As a result, our all-in-one porous membrane possesses full protective abilities in GBR.

A bi-layered asymmetric membrane loaded with demineralized dentin matrix for guided bone regeneration

OBJECTIVES

Guided bone regeneration (GBR) is a well-established method for repairing hard tissue deficiency in reconstructive dentistry. The aim of this study was to investigate the barrier function, osteogenic activity and immunomodulatory ability of a novel bi-layered asymmetric membrane loaded with demineralized dentin matrix (DDM).

METHODS

DDM particles were harvested from healthy, caries-free permanent teeth. Electrospinning technique was utilized to prepare bi-layered DDM-loaded poly(lactic-co-glycolic acid) (PLGA)/poly(lactic acid) (PLA) membranes (abbreviated as DPP bilayer membranes). We analyzed the membranes' surface properties, cytocompatibility and barrier function, and evaluated their osteogenic activity in vitro. In addition, its effects on the osteogenic immune microenvironment were also investigated.

RESULTS

Synthetic DPP bilayer membranes presented suitable surface characteristics and satisfactory cytocompatibility. Transwell assays showed significant fewer migrated cells by the DPP bilayer membranes compared with blank control, with or without in vitro degradation (all P < 0.001). In vitro experiments indicated that our product elevated messenger ribonucleic acid (mRNA) expression levels of osteogenic genes alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN) and runt-related transcription factor 2 (Runx2). Among all groups, 20% DPP bilayer membrane displayed highest ALP activity (P < 0.001). Furthermore, DPP bilayer membranes enhanced the mRNA expression of M2 macrophage markers and increased the proportion of CD206+ M2 macrophages by 100% (20% DPP: P < 0.001; 30% DPP: P < 0.001; 40% DPP: P < 0.05), thus exerting an inflammation suppressive effect.

CONCLUSIONS

DPP bilayer membranes exhibited notable biological safety and osteogenic activity in vitro, and have potential as a prospective candidate for GBR approach in the future.

Application of CAD-CAM Technologies for Maxillofacial Bone Regeneration: A Narrative Review of the Clinical Studies

The application of regenerative methods in treating maxillofacial defects can be categorized as functional bone regeneration in which scaffolds without protection are used and in-situ bone regeneration in which a protected healing space is created to induce bone formation. It has been shown that functional bone regeneration can reduce surgical time and obviate the necessity of autogenous bone grafting. However, studies mainly focused on applying this method to reconstruct minor bone effects, and more investigation concerning the large defects is required. In terms of in situ maxillofacial bone regeneration with the help of CAD-CAM technologies, the present data have suggested feasible mesh rigidity, perseverance of the underlying space, and apt augmentative results with CAD-CAM-based individualized Ti meshes. However, complications, including dehiscence and mesh exposure, coupled with consequent graft loss, infection and impeded regenerative rates have also been reported.

Collagen-Based Medical Devices for Regenerative Medicine and Tissue Engineering

Assisted reproductive technologies are key to solving the problems of aging and organ defects. Collagen is compatible with living tissues and has many different chemical properties; it has great potential for use in reproductive medicine and the engineering of reproductive tissues. It is a natural substance that has been used a lot in science and medicine. Collagen is a substance that can be obtained from many different animals. It can be made naturally or created using scientific methods. Using pure collagen has some drawbacks regarding its physical and chemical characteristics. Because of this, when collagen is processed in various ways, it can better meet the specific needs as a material for repairing tissues. In simpler terms, collagen can be used to help regenerate bones, cartilage, and skin. It can also be used in cardiovascular repair and other areas. There are different ways to process collagen, such as cross-linking it, making it more structured, adding minerals to it, or using it as a carrier for other substances. All of these methods help advance the field of tissue engineering. This review summarizes and discusses the current progress of collagen-based materials for reproductive medicine.

Alveolar Ridge Preservation with a Novel Cross-Linked Collagen Sponge: Histological Findings from a Case Report

Alveolar ridge preservation (ARP) is a well-documented procedure to maintain bone volume after tooth extraction in order to place implants. However, at the end of the healing process, the residual biomaterial that is not reabsorbed remains embedded in the bone over time. Ribose cross-linked biomaterials demonstrated their ability to promote osteoconduction and complete resorption. The aim of this study was to evaluate the histological healing pattern of a novel ribose cross-linked collagen sponge used as a grafting material left exposed in human sockets at the time of tooth extraction. On a single patient, non-restorable lower first molars were extracted on both sides, and a ribose cross-linked collagen sponge was placed bilaterally in the cavities and left uncovered at the end of the surgery. After six months, core biopsies were taken immediately prior to implant placement; after the sample preparation, a histological analysis was performed. The results are very promising for substitution with newly formed bone and the amount of residual material. Ribose cross-linked collagen sponge could represent a valid alternative to conventional biomaterials for ARP procedures with no need for flap advancement and/or the addition of a membrane to cover the graft, reducing the invasiveness, complexity, and costs of the treatment.

A New Concept of Horizontal Bone Augmentation Using Collagen Bovine Bone Blocks Without Membrane at Implant Placement: A Preliminary Study

Purpose

A buccal bone thickness (BBT) of at least 1.8-2 mm is necessary to ensure long-term implant stability, and a bone grafting procedure is commonly needed to restore this BBT. This study aims to prove the effectiveness of a novel bone augmentation technique in which minero-organic bone substitutes are solely used to restore adequate BBT, excluding the need for coverage membranes.

Methods

Fifty partially edentulous patients having a residual bone width ranging between 5 and 6 mm were enrolled in this study. The horizontal buccal defects were grafted simultaneously at implant placement. Minero-organic collagen bovine bone blocks (CBBB) were placed on the outer side of the buccal bone wall, and adapted to the defect morphology through slow compressive movements. The grafted sites were not covered with any type of membrane nor stabilized with fixation pins. Cone-beam computed tomography scans were obtained pre-operatively, immediately post-surgery, and four months later. Scans were superimposed on the ITK-Snap software to measure the amount of bone gain and assess the percentage of CBBB resorption. Measurements were effectuated at four different levels apically to crestal level.

Results

Radiographic findings showed BBT increase and CBBB resorption in all cases, four months post-grafting. A mean horizontal bone gain of 1.39 mm was calculated at a crestal level.

Conclusion

Based on these findings, it appears that this novel and user-friendly bone grafting technique can achieve positive outcomes from both clinical and radiographic perspectives.

Barrier membranes for periodontal guided bone regeneration: a potential therapeutic strategy

Periodontal disease is one of the most common oral diseases with the highest incidence world-wide. In particular, the treatment of periodontal bone defects caused by periodontitis has attracted extensive attention. Guided bone regeneration (GBR) has been recognized as advanced treatment techniques for periodontal bone defects. GBR technique relies on the application of barrier membranes to protect the bone defects. The commonly used GBR membranes are resorbable and non-resorbable. Resorbable GBR membranes are divided into natural polymer resorbable membranes and synthetic polymer resorbable membranes. Each has its advantages and disadvantages. The current research focuses on exploring and improving its preparation and application. This review summarizes the recent literature on the application of GBR membranes to promote the regeneration of periodontal bone defects, elaborates on GBR development strategies, specific applications, and the progress of inducing periodontal bone regeneration to provide a theoretical basis and ideas for the future application of GBR membranes to promote the repair of periodontal bone defects.

Long-Term Temporospatial Complementary Relationship between Degradation and Bone Regeneration of Mg-Al Alloy

The utilization of guided tissue regeneration membranes is a significant approach for enhancing bone tissue growth in areas with bone defects. Biodegradable magnesium alloys are increasingly being used as guided tissue regeneration membranes due to their outstanding osteogenic properties. However, the degradation rates of magnesium alloy bone implants documented in the literature tend to be rapid. Moreover, many studies focus only on the initial 3-month period post-implantation, limiting their applicability and impeding clinical adoption. Furthermore, scant attention has been given to the interplay between the degradation of magnesium alloy implants and the adjacent tissues. To address these gaps, this study employs a well-studied magnesium-aluminum (Mg-Al) alloy membrane with a slow degradation rate. This membrane is implanted into rat skull bone defects and monitored over an extended period of up to 48 weeks. Observations are conducted at various intervals (2, 4, 8, 12, 24, and 48 weeks) following the implantation. Assessment of degradation behavior and tissue regeneration response is carried out using histological sections, micro-CT scans, and scanning electron microscopy (SEM). The findings reveal that the magnesium alloy membranes demonstrate remarkable biocompatibility and osteogenic capability over the entire observation duration. Specifically, the Mg-Al alloy membranes sustain their structural integrity for 8 weeks. Notably, their osteogenic ability is further enhanced as a corrosion product layer forms during the later stages of implantation. Additionally, our in vitro experiments employing extracts from the magnesium alloy display a significant osteogenic effect, accompanied by a notable increase in the expression of osteogenic-related genes. Collectively, these results strongly indicate the substantial potential of Mg-Al alloy membranes in the context of guided tissue regeneration.

Regeneration of Intrabony Defects Using a Novel Magnesium Membrane

Background and Objectives: Due to their specific morphology, the regeneration of intrabony defects (IBDs) represents one of the greatest challenges for clinicians. Based on the specific properties of a magnesium membrane, a new approach for the surgical treatment of IBD was developed. The surgical procedure was described using a series of three cases. Materials and Methods: The patients were healthy individuals suffering from a severe form of periodontitis associated with IBD. Based on radiographic examination, the patients had interproximal bone loss of at least 4 mm. Due to its good mechanical properties, it was easy to cut and shape the magnesium membrane into three different shapes to treat the specific morphology of each IBD. In accordance with the principles of guided bone regeneration, a bovine xenograft was used to fill the IBD in all cases. Results: After a healing period of 4 to 6 months, successful bone regeneration was confirmed using radiological analysis. The periodontal probing depth (PPD) after healing showed a reduction of 1.66 ± 0.29 mm. Conclusions: Overall, the use of the different shapes of the magnesium membrane in the treatment of IBD resulted in a satisfactory functional and esthetic outcome.

The application of CGF combined with GBR in alveolar bone increment for patients with anxiety disorder: A rare case report and literature review

RATIONALE

Selective serotonin reuptake inhibitors (SSRIs), one of the commonly used anti-anxiety drugs, may have impacts on bone metabolism and potentially lead to drug-induced osteoporosis. The traditional approach of oral implantation in individuals with both anxiety disorder and drug-induced osteoporosis poses a significant challenge. To address this issue, concentrated growth factor (CGF) has been utilized in patients undergoing concurrent alveolar ridge augmentation during oral implantation, resulting in favorable clinical outcomes. Consequently, combining CGF with guided bone regeneration (GBR) in alveolar bone increment may represent a promising new surgical approach for such patients. In this report, we present a case study of a 25-year-old male with anxiety disorder and drug-induced osteoporosis, in who CGF combined with GBR was employed in alveolar bone increment.

PATIENT CONCERNS

This article reports the case of a 25-year-old male who underwent cone beam computed tomography (CBCT) due to the absence of his right lower second molar for a period of six months. The CBCT scan revealed significant bone defects, which were attributed to the tooth loss and prolonged use of anti-anxiety drugs. Consequently, the patient sought medical assistance from our department.

DIAGNOSES

Based on the patient's self-report, he was diagnosed with an anxiety disorder. Additionally, the CBCT scan confirmed the loss of the right mandibular second molar and revealed the presence of dental irregularity and an alveolar bone defect.

INTERVENTIONS

During the patient's course of treatment with anti-anxiety medication, a combination of CGF and GBR was employed for the simultaneous implantation of the missing right mandibular second molar, along with bone augmentation.

OUTCOMES

The patient had a follow-up visit two weeks after the surgical procedure, and the wound in the operation area had healed satisfactorily. Six months later, CBCT images revealed excellent osseointegration. The buccal and lingual width of the alveolar bone measured 6.95mm, which was an increase of 1.35mm compared to the pre-implantation stage.

LESSONS

This article presents a case study in which CGF combined with GBR were utilized to address alveolar bone augmentation during the implantation phase in patients taking anti-anxiety medication. The results demonstrated that CGF combined with GBR, as a cutting-edge platelet concentrate technique, could effectively stimulate bone tissue proliferation in individuals who have been on long-term anti-anxiety medication, specifically in oral implant areas. This approach can help prevent poor osseointegration, promote higher osseointegration rates, and facilitate wound healing.

Resorbable GBR Scaffolds in Oral and Maxillofacial Tissue Engineering: Design, Fabrication, and Applications

Guided bone regeneration (GBR) is a promising technique in bone tissue engineering that aims to replace lost or injured bone using resorbable scaffolds. The promotion of osteoblast adhesion, migration, and proliferation is greatly aided by GBR materials, and surface changes are critical in imitating the natural bone structure to improve cellular responses. Moreover, the interactions between bioresponsive scaffolds, growth factors (GFs), immune cells, and stromal progenitor cells are essential in promoting bone regeneration. This literature review comprehensively discusses various aspects of resorbable scaffolds in bone tissue engineering, encompassing scaffold design, materials, fabrication techniques, and advanced manufacturing methods, including three-dimensional printing. In addition, this review explores surface modifications to replicate native bone structures and their impact on cellular responses. Moreover, the mechanisms of bone regeneration are described, providing information on how immune cells, GFs, and bioresponsive scaffolds orchestrate tissue healing. Practical applications in clinical settings are presented to underscore the importance of these principles in promoting tissue integration, healing, and regeneration. Furthermore, this literature review delves into emerging areas of metamaterials and artificial intelligence applications in tissue engineering and regenerative medicine. These interdisciplinary approaches hold immense promise for furthering bone tissue engineering and improving therapeutic outcomes, leading to enhanced patient well-being. The potential of combining material science, advanced manufacturing, and cellular biology is showcased as a pathway to advance bone tissue engineering, addressing a variety of clinical needs and challenges. By providing this comprehensive narrative, a detailed, up-to-date account of resorbable scaffolds' role in bone tissue engineering and their transformative potential is offered.

Enhancing the mechanical properties and surface morphology of individualized Ti-mesh fabricated through additive manufacturing for the treatment of alveolar bone defects

Titanium meshes are widely utilized in alveolar bone augmentation, and this study aims to enhance the properties of titanium meshes through heat treatment (HT) and the synergistic finishing technology of electric field and flow field (EFSF). Our findings illustrate that the titanium mesh exhibits improved mechanical properties following HT treatment. The innovative EFSF technique, in combination with HT, has a substantial impact on improving the surface properties of titanium meshes. HT initiates grain fusion and reduces surface pores, resulting in enhanced tensile and elongation properties. EFSF further enhances these improvements by significantly reducing surface roughness and eliminating adhered titanium powder, a byproduct of selective laser melting printing. Increased hydrophilicity and surface-free energy are achieved after EFSF treatment. Notably, the EFSF-treated titanium mesh exhibits reduced bacterial adhesion and is non-toxic to osteoblast proliferation. These advancements increase its suitability for clinical alveolar bone augmentation.

Osteogenic differentiation and reconstruction of mandible defects using a novel resorbable membrane: An in vitro and in vivo experimental study

To evaluate the cellular response of both an intact fish skin membrane and a porcine-derived collagen membrane and investigate the bone healing response of these membranes using a translational, preclinical, guided-bone regeneration (GBR) canine model. Two different naturally sourced membranes were evaluated in this study: (i) an intact fish skin membrane (Kerecis Oral®, Kerecis) and (ii) a porcine derived collagen (Mucograft®, Geistlich) membrane, positive control. For the in vitro experiments, human osteoprogenitor (hOP) cells were used to assess the cellular viability and proliferation at 24, 48, 72, and 168 h. ALPL, COL1A1, BMP2, and RUNX2 expression levels were analyzed by real-time PCR at 7 and 14 days. The preclinical component was designed to mimic a GBR model in canines (n = 12). The first step was the extraction of premolars (P1-P4) and the 1st molars bilaterally, thereby creating four three-wall box type defects per mandible (two per side). Each defect site was filled with bone grafting material, which was then covered with one of the two membranes (Kerecis Oral® or Mucograft®). The groups were nested within the mandibles of each subject and membranes randomly allocated among the defects to minimize potential site bias. Samples were harvested at 30-, 60-, and 90-days and subjected to computerized microtomography (μCT) for three-dimensional reconstruction to quantify bone formation and graft degradation, in addition to histological processing to qualitatively analyze bone regeneration. Neither the intact fish skin membrane nor porcine-based collagen membrane presented cytotoxic effects. An increase in cell proliferation rate was observed for both membranes, with the Kerecis Oral® outperforming the Mucograft® at the 48- and 168-hour time points. Kerecis Oral® yielded higher ALPL expression relative to Mucograft® at both 7- and 14-day points. Additionally, higher COL1A1 expression was observed for the Kerecis Oral® membrane after 7 days but no differences were detected at 14 days. The membranes yielded similar BMP2 and RUNX2 expression at 7 and 14 days. Volumetric reconstructions and histologic micrographs indicated gradual bone ingrowth along with the presence of particulate bone grafts bridging the defect walls for both Kerecis Oral® and Mucograft® membranes, which allowed for the reestablishment of the mandible shape after 90 days. New bone formation significantly increased from 30 to 60 days, and from 60 to 90 days in vivo, without significant differences between membranes. The amount of bovine grafting material (%) within the defects significantly decreased from 30 to 90 days. Collagen membranes led to an upregulation of cellular proliferation and adhesion along with increased expression of genes associated with bone healing, particularly the intact fish skin membrane. Despite an increase in the bone formation rate in the defect over time, there was no significant difference between the membranes.

Non-Thermal Plasma Treatment of Poly(tetrafluoroethylene) Dental Membranes and Its Effects on Cellular Adhesion

Non-resorbable dental barrier membranes entail the risk of dehiscence due to their smooth and functionally inert surfaces. Non-thermal plasma (NTP) treatment has been shown to increase the hydrophilicity of a biomaterials and could thereby enhance cellular adhesion. This study aimed to elucidate the role of allyl alcohol NTP treatment of poly(tetrafluoroethylene) in its cellular adhesion. The materials (non-treated PTFE membranes (NTMem) and NTP-treated PTFE membranes (PTMem)) were subjected to characterization using scanning electron microscopy (SEM), contact angle measurements, X-ray photoelectron spectroscopy (XPS), and electron spectroscopy for chemical analysis (ESCA). Cells were seeded upon the different membranes, and cellular adhesion was analyzed qualitatively and quantitatively using fluorescence labeling and a hemocytometer, respectively. PTMem exhibited higher surface energies and the incorporation of reactive functional groups. NTP altered the surface topography and chemistry of PTFE membranes, as seen through SEM, XPS and ESCA, with partial defluorination and polymer chain breakage. Fluorescence labeling indicated significantly higher cell populations on PTMem relative to its untreated counterparts (NTMem). The results of this study support the potential applicability of allyl alcohol NTP treatment for polymeric biomaterials such as PTFE-to increase cellular adhesion for use as dental barrier membranes.

Guided Bone Regeneration Using Barrier Membrane in Dental Applications

Guided bone regeneration (GBR) is a widely used technique in preclinical and clinical studies due to its predictability. Its main purpose is to prevent the migration of soft tissue into the osseous wound space, while allowing osseous cells to migrate to the site. GBR is classified into two main categories: resorbable and non-resorbable membranes. Resorbable membranes do not require a second surgery but tend to have a short resorption period. Conversely, non-resorbable membranes maintain their mechanical strength and prevent collapse. However, they require removal and are susceptible to membrane exposure. GBR is often used with bone substitute graft materials to fill the defect space and protect the bone graft. The membrane can also undergo various modifications, such as surface modification and biological factor loading, to improve barrier functions and bone regeneration. In addition, bone regeneration is largely related to osteoimmunology, a new field that focuses on the interactions between bone and the immune system. Understanding these interactions can help in developing new treatments for bone diseases and injuries. Overall, GBR has the potential to be a powerful tool in promoting bone regeneration. Further research in this area could lead to advancements in the field of bone healing. This review will highlight resorbable and non-resorbable membranes with cellular responses during bone regeneration, provide insights into immunological response during bone remodeling, and discuss antibacterial features.

Complications following alveolar ridge augmentation procedures

Oral rehabilitation through implant supported dental restorations often requires a ridge augmentation procedure (RAP) prior to implant fixture placement since tooth extraction/loss results in alveolar ridge deficiencies. Although RAP-related surgical techniques and biomaterials have been in practice for several decades, outcomes are not always predictable. Post-surgical complications experienced during the early or late wound healing phases may jeopardize the targeted ideal ridge dimensions, required for implant fixture placement, and may have other consequences, such as negatively impacting the patient's quality of life. This review describes reported post-surgical complications following RAP under the following subtitles: complications by tissue type, complications in function and aesthetics, complications by healing time, complications by biomaterial type, and complications by surgical protocol modalities. Specifically, RAP performed by using particulate bone graft substitutes and related complications are explored. Modalities developed to prevent/manage these complications are also discussed.

Membrane barriers for guided bone regeneration: An overview of available biomaterials

Dental implants revolutionized the treatment options for restoring form, function, and esthetics when one or more teeth are missing. At sites of insufficient bone, guided bone regeneration (GBR) is performed either prior to or in conjunction with implant placement to achieve a three-dimensional prosthetic-driven implant position. To date, GBR is well documented, widely used, and constitutes a predictable and successful approach for lateral and vertical bone augmentation of atrophic ridges. Evidence suggests that the use of barrier membranes maintains the major biological principles of GBR. Since the material used to construct barrier membranes ultimately dictates its characteristics and its ability to maintain the biological principles of GBR, several materials have been used over time. This review, summarizes the evolution of barrier membranes, focusing on the characteristics, advantages, and disadvantages of available occlusive barrier membranes and presents results of updated meta-analyses focusing on the effects of these membranes on the overall outcome.

A Prospective Study of the Assessment of the Efficacy of a Biodegradable Poly(l-lactic acid/ε-caprolactone) Membrane for Guided Bone Regeneration

Biodegradable guided bone regeneration (GBR) membranes consist primarily of collagen and aliphatic polyesters. This study assessed the comparative efficacy of a poly(l-lactic-caprolactone) [P(LA/CL)] membrane versus that of a collagen membrane in GBR. Patients requiring GBR simultaneously or before dental implant placement in edentulous regions were randomly assigned to one of two membranes. Within each membrane, they were subdivided into 3 groups: dental implants were placed simultaneously with GBR in groups A and B, and 180 days post-GBR in group C. The augmented bone width was measured at 1, 3, and 6 mm from the implant's neck (groups A and B) or the reference line (group C), utilizing cone-beam computed tomography images, immediately and 150 days post-surgery. A histological study was performed to evaluate bone formation in group C. No adverse events were observed. In the collagen group, the absorbed ratios of the augmented bone were 40.9 ± 36.7%, 29.4 ± 30.1%, and 11.1 ± 22.0% at 1, 3, and 6 mm, respectively; the ratio at 6 mm was significantly lower than that at 1 mm (p = 0.0442). In the P(LA/CL) group, those were 26.2 ± 27.3%, 17.1 ± 19.7%, and 13.3 ± 16.4% at 1, 3, and 6 mm, respectively, with no significant difference at each point. No significant inter-membrane differences were observed. The bone augmentation potential of the P(LA/CL) membrane matched that of the collagen membrane. P(LA/CL) could be used as a safe and effective membrane in GBR.

Blood Clotting Dissolution in the Presence of a Magnetic Field and Preliminary Study with MG63 Osteoblast-like Cells-Further Developments for Guided Bone Regeneration?

BACKGROUND

The influence of a magnetic field on the activation of bone cells and remodelling of alveolar bone is known to incite bone regeneration. Guided Bone Regeneration (GBR) aims to develop biomimetic scaffolds to allow for the functioning of the barrier and the precise succession of wound healing steps, including haemostasis. The effect of a magnetic field on blood clot dissolution has not been studied yet.

METHODS

We conducted a methodological study on the clot stability in the presence of a static magnetic field (SMF). Preformed whole blood (WB) clots were treated with either a broad proteolytic enzyme (trypsin) or a specific fibrinolytic agent, i.e., tissue-type plasminogen activator (t-PA). MG63 osteoblast-like cells were added to preformed WB clots to assess cell proliferation.

RESULTS

After having experienced a number of clotting and dissolution protocols, we obtained clot stability exerted by SMF when tissue factor (for clotting) and t-PA + plasminogen (for fibrinolysis) were used. WB clots allowed osteoblast-like cells to survive and proliferate, however no obvious effects of the magnetic field were noted.

CONCLUSIONS

Paramagnetic properties of erythrocytes may have influenced the reduction in clot dissolution. Future studies are warranted to fully exploit the combination of magnetic forces, WB clot and cells in GBR applied to orthodontics and prosthodontics.

Guided Bone Regeneration Using a Novel Magnesium Membrane: A Literature Review and a Report of Two Cases in Humans

Guided bone regeneration (GBR) is a common procedure used to rebuild dimensional changes in the alveolar ridge that occur after extraction. In GBR, membranes are used to separate the bone defect from the underlying soft tissue. To overcome the shortcomings of commonly used membranes in GBR, a new resorbable magnesium membrane has been developed. A literature search was performed via MEDLINE, Scopus, Web of Science and PubMed in February 2023 for research on magnesium barrier membranes. Of the 78 records reviewed, 16 studies met the inclusion criteria and were analyzed. In addition, this paper reports two cases where GBR was performed using a magnesium membrane and magnesium fixation system with immediate and delayed implant placement. No adverse reactions to the biomaterials were detected, and the membrane was completely resorbed after healing. The resorbable fixation screws used in both cases held the membranes in place during bone formation and were completely resorbed. Therefore, the pure magnesium membrane and magnesium fixation screws were found to be excellent biomaterials for GBR, which supports the findings of the literature review.

Physical Characteristics and Biocompatibility of 3D-Printed Polylactic-Co-Glycolic Acid Membranes Used for Guided Bone Regeneration

Bioresorbable polymeric membranes for guided bone regeneration (GBR) were fabricated using the three-dimensional printing technique. Membranes made of polylactic-co-glycolic acid (PLGA), which consist of lactic acid (LA) and glycolic acid in ratios of 10:90 (group A) and 70:30 (group B), were compared. Their physical characteristics including architecture, surface wettability, mechanical properties, and degradability were compared in vitro, and their biocompatibilities were compared in vitro and in vivo. The results demonstrated that the membranes of group B had mechanical strength and could support the proliferation of fibroblasts and osteoblasts significantly better than those of group A (p < 0.05). The degradation rate in Group B was significantly lower than that in Group A, but they significantly produced less acidic environment (p < 0.05). In vivo, the membranes of group B were compared with the commercially available collagen membranes (group C). The amount of newly formed bone of rat's calvarial defects covered with the membranes of group C was stable after week 2, whereas that of group B increased over time. At week 8, the new bone volumes in group B were greater than those in group C (p > 0.05). In conclusion, the physical and biological properties of the PLGA membrane (LA:GA, 70:30) were suitable for GBR.

Platelet rich fibrin is not a barrier membrane! Or is it?

Platelet-rich fibrin (PRF) is widely used in dentistry and other fields of medicine, and its use has become popular in dental implantology. In several published studies, PRF has been used as a barrier membrane. A barrier membrane is a sheet of a certain material that acts as a biological and mechanical barrier against the invasion of cells that are not involved in bone formation, such as epithelial cells. Among the basic requirements of a 'barrier membrane, occlusivity, stiffness, and space maintenance are the criteria that PRF primarily lacks; therefore, it does not fall under the category of barrier membranes. However, there is evidence that PRF membranes are useful in significantly improving wound healing. Does the PRF membrane act as a barrier? Should we think of adding or subtracting some points from the ideal requirements of a barrier membrane, or should we coin a new term or concept for PRF that will incorporate some features of a barrier membrane and be a combination of tissue engineering and biotechnology? This review is aimed at answering the basic question of whether the PRF membrane should be considered a barrier membrane or whether it is something more beyond the boundaries of a barrier membrane.

Effects of Minocycline Hydrochloride as an Adjuvant Therapy for a Guided Bone Augmentation Procedure in The Rat Calvarium

This in vivo study reports the influence of minocycline-HCl administration on extra-skeletal bone generation in a Guided Bone Augmentation model, utilizing titanium caps placed on the intact as well as perforated calvaria of rats. The test group was administered 0.5 mg/mL minocycline-HCl with the drinking water, and the amount of bone tissue in the caps was quantified at three time points (4, 8 and 16 weeks). A continuously increased tissue fill was observed in all groups over time. The administration of minocycline-HCl as well as perforation of the calvaria increased this effect, especially with regard to mineralization. The strongest tissue augmentation, with 1.8 times that of the untreated control group, and, at the same time, the most mineralized tissue (2.3× over untreated control), was produced in the combination of both treatments, indicating that systemic administration of minocycline-HCl has an accelerating and enhancing effect on vertical bone augmentation.

Effect of ozone therapy on the modulation of inflammation and on new bone formation in critical defects of rat calvaria filled with autogenous graft

OBJECTIVE

The aim of this study was to evaluate the effect of ozone therapy on new bone formation and inflammation modulation in defects of rat calvaria filled with autogenous bone.

MATERIAL AND METHODS

Critical size defects were created in the calvaria of 24 male Wistar rats. The animals were randomly divided into four groups according to the treatment: G1: clot; G2: clot and covered with xenogenic membrane; G3: particulate autogenous bone graft; G4: autogenous bone graft and application of 3 mL O₂/O₃ gas mixture (10 µg/ml). The defects were filled immediately after surgery with a bilateral retroauricular application, in the region immediately above the incision. After 21 days, the animals were euthanized, and the samples were processed for morphometric evaluations designed to measure both the intensity of the inflammatory infiltrate, and the presence of new bone formation in the defect.

RESULTS

The results showed a lower inflammation score and higher mean of newly formed bone in the region of the defect for the group associated with ozone therapy (G4). The bone formed in the region of the defect could be observed as being more lamellar and mineralized in the case of associated ozone therapy.

CONCLUSION

Ozone therapy represents a promising adjuvant therapy to accelerate tissue regeneration.

In vivo evaluation of a collagen membrane in bone neoformation: A morphological and histomorphometric study

OBJECTIVE

Guided bone regeneration (GBR) is a technique that involves the placement of mechanical barriers to protect the blood clot, and create an isolated space to prevent competition from epithelial and connective tissues in bone augmentation treatments. Collagen membranes stand out from other materials available for performing regenerative surgeries, and are widely used because of their ability to promote cell adhesion and homeostasis, and their biocompatibility, ease of handling, and low immunogenicity. In this context, researchers have investigated xenogenic membranes/barriers that cost less and have slower resorption rates. The current study aimed to assess the osteogenic potential induced by a crosslinked, synthesized xenogenic membrane 100 µm thick when applied in vivo to critical defects in rat calvaria.

MATERIAL AND METHODS

Critical size defects were created in the calvaria of thirty male Wistar rats, and randomly divided into the following two groups: G1 - clot covered with a commercial xenogenic membrane (Lumina-Coat®, Criteria, Brazil), and G2 - clot covered with a synthesized xenogenic membrane. The animals were euthanized after 7, 15 and 30 days, and samples of calvaria were processed to perform morphometric evaluations to measure bone neoformation in the defect region. In addition, ultrastructural characterization of the collagen membranes was performed by scanning electron microscope. The quantitative analyses were carried out by adopting a significance level of 5%.

RESULTS

The ultrastructural characterization revealed that the synthesized membrane had thicker collagen fibers and a more cohesive surface, compared with the Lumina-Coat® collagen membrane (G1). There was no significant difference in bone neoformation between the membranes (p>0.05), at any of the time periods analyzed. The bone quantification area increased significantly over time for both membranes (p<0.05).

CONCLUSION

The synthesized membrane exhibited morphological characteristics similar to those of the commercial membrane evaluated, allowed potentially active participation in the bone neoformation process, and served as a low-cost alternative for GBR procedures.

Surface characteristics and in vitro biocompatibility of surface-modified titanium foils as a regenerative barrier membrane for guided bone regeneration

This study evaluated surface characteristics and biocompatibility of surface-modified thin titanium (Ti) foils as a regenerative barrier membrane for future application in guided bone regeneration (GBR) surgery to augment atrophic alveolar bone. Anodic oxidation and post-heat treatment were performed to prepare various Ti foil samples. Then, the in vitro soft and hard tissue compatibility of the samples was evaluated by examining the cell responses using primary human gingival fibroblasts (HGFs) and MG63 human osteoblast-like cells. Investigated Ti foil samples showed marked differences in physicochemical surface properties. Additional 400°C heat treatment applied to the anodized Ti surface led to formation of an anatase titanium dioxide structure and well-organized nanoscale protrusions, and significantly increased surface wettability. Anodization and heat treatment enhanced the growth of HGFs and MG63 cells in Ti foil samples. Additional heat treatment for 10 and 30 min further significantly improved the response of HGFs including spreading and proliferation, and upregulated the mRNA expression of cell adhesion- and maturation-related genes as well as the osteoblast differentiation of MG63 cells. Ti foil sample with thin oxide coating obtained by a 30 min heat treatment exhibited poor clinical plasticity as a regenerative barrier membrane, which showed complete coating failure in the bending test. Our results indicate that anatase Ti oxide coating of a specific film thickness with nanoscale surface protrusion morphology and hydrophilic characteristics obtained by anodization and post-heat treatment would be an effective approach as a biocompatible Ti regenerative membrane for inducing better regeneration of both gingival tissue and bone.

Differences in Mechanical and Physicochemical Properties of Several PTFE Membranes Used in Guided Bone Regeneration

Non-resorbable PTFE membranes are frequently used in dental-guided bone regeneration (GBR). However, there is a lack of detailed comparative studies that define variations among commonly used PTFE membranes in daily dental clinical practice. The aim of this study was to examine differences in physicochemical and mechanical properties of several recent commercial PTFE membranes for dental GBR (Cytoplast^TM TXT-200, permamem^®, NeoGen^®, Surgitime, OsseoGuard^®-TXT, OsseoGuard^®-NTXT). Such differences have been rarely recorded so far, which might be a reason for the varied clinical results. For that reason, we analyzed their surface architecture, chemical composition, tensile strength, Young's modulus, wettability, roughness, density, thickness and porosity. SEM revealed different microarchitectures among the non-textured membranes; the textured ones had hexagonal indentations and XPS indicated an identical spectral portfolio in all membranes. NeoGen^® was determined to be the strongest and OsseoGuard^®-TXT was the most elastic. Wettability and roughness were highest for Surgitime but lowest for OsseoGuard^®-NTXT. Furthermore, permamem^® was the thinnest and NeoGen^® was identified as the thickest investigated GBR membrane. The defect volumes and defect volume ratio (%) varied significantly, indicating that permamem^® had the least imperfect structure, followed by NeoGen^® and then Cytoplast ^TM TXT-200. These differences may potentially affect the clinical outcomes of dental GBR procedures.

High porosity 3D printed titanium mesh allows better bone regeneration

BACKGROUND

Most patients with insufficient bone mass suffer from severe horizontal or vertical bone defects in oral implant surgery. The purpose of this study was to compare the bone regeneration effects of titanium meshes with different porosity in the treatment of bone defects.

METHODS

Nine beagle dogs were equally divided into three groups based on execution time. Three months after the extraction of the first to fourth premolars of the mandible, three bone defects were randomly made in the mandible. Bone particles and three kinds of three-dimensional (3D) printed titanium nets with different porosities (low porosity group (LP), 55%; medium porosity group (MP), 62%; and high porosity group (HP), 68%) were replanted in situ. The beagles were killed 4, 8, and 12 weeks after surgery. Formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with micro-CT, basic fuchsin staining, and toluidine blue staining.

RESULTS

Micro-CT analysis showed that the trabecular thickness, trabecular number, and bone volume fraction of the HP group were higher than those of the other two groups. Moreover, the trabecular separation of the HP group decreased slightly and was lower than that of the MP and LP groups. Histological staining analysis showed that the trabecular number in the HP group was higher than in the other two groups at 8 and 12 weeks, and the bone volume fraction of the HP was higher than that in the other two groups at 12 weeks. Moreover, the trabecular thickness of the MP was higher than that of the LP group at 12 weeks and the trabecular separation was lower in the HP group at 4 and 8 weeks. The differences were statistically significant (p < 0.05).

CONCLUSION

A 3D printed titanium mesh with HP in a certain range may have more advantages than a titanium mesh with LP in repairing large bone defects.

Vertical Bonegraft Wrap-A Technique to Increase Soft Tissue Volume in Paranasal Region

This study presents a technique to gain soft tissue volume in the paranasal region, using a xenogenous bonegraft wrap with a porcine pericardium collagen membrane in a patient with severe paranasal deficiency and midfacial hypoplasia. The technique consisted of using particulate bonegraft that is wrapped on collagen membrane and placed vertically and parallel to the lateral wall of the nasal cavity, over maxillary osteotomies. In a tomographic analysis of linear and volumetric measurements with 14 days and 6 months after the procedure, it was observed good stability of the vertical bonegraft wrap, as well as volume gain in the paranasal region and low absorption rate of the grafted material. This technique presented a satisfactory clinical result, promoting an improvement in facial harmony with gain volume in the paranasal region, guaranteeing greater predictability in the treatment of a patient with significant maxillary advancement surgery.

Titanium Membranes with Hydroxyapatite/Titania Bioactive Ceramic Coatings: Characterization and In Vivo Biocompatibility Testing

Titanium membranes and meshes are used for the repair of trauma, tumors, and hernia in dentistry and maxillofacial and abdominal surgery. But such membranes demonstrate the limited effectiveness of integration in recipients due to their bioinertness. In this study, we prepared titania oxide (by microarc oxidation) and/or HAp (by electrophoresis deposition) coatings with alginate soaking. We used annealing at 700 °C for 2.5 h for HAp crystallinity increasing with achievement of an acceptable Ca²⁺ release rate. The feedstock HAp and prepared coatings were characterized by X-ray diffraction, IR spectroscopy, electron and optical confocal microscopy, and thermal analysis, as well as the in vitro study of solubility in saline and in vivo tests with the animal model of subcutaneous implantation (with Wistar rats). Biocompatible compounds were found for all deposited coatings. We noted that the best biological response was detected for the annealed Ca-P/TiO₂ bilayer with alginate binding. In this case, the coating crystallinity was ≈40.5-50.0%. The Ca²⁺ release rate was 2.042 ± 0.058%/mm² at 168 h after immersion in saline. Thin and mature tissue capsules with minimal inflammation and vascularization were found in histological sections. We did not detect any unwanted responses around the implants, including inflammation infiltration, suppuration, bacterial infections, tissue lyses, and, finally, implant rejection. This information is expected to be useful for understanding the properties of bioactive ceramic coatings and improving the quality of medical care in dentistry and maxillofacial surgery and other applications of titanium membranes in medicine.

Degradable Pure Magnesium Used as a Barrier Film for Oral Bone Regeneration

The barrier membrane plays an extremely critical role in guided bone regeneration (GBR), which determines the success or failure of GBR technology. In order to obtain barrier membranes with high mechanical strength and degradability, some researchers have focused on degradable magnesium alloys. However, the degradation rate of pure Mg-based materials in body fluids is rather fast, thus posing an urgent problem to be solved in oral clinics. In this study, a novel micro-arc oxidation (MAO) surface-treated pure Mg membrane was prepared. Electrochemical tests, immersion experiments and in vivo experiments were carried out to investigate its potential use as a barrier membrane. The experimental results showed that the corrosion resistance of a pure Mg membrane treated by MAO is better than that of the uncoated pure Mg. The results of cell experiments showed no obvious cytotoxicity, which suggests the enhanced differentiation of osteoblasts. At the same time, the MAO-Mg membrane showed better biological activity than the pure Ti membrane in the early stage of implantation, exhibiting relatively good bone regeneration ability. Consequently, the MAO membrane has been proven to possess good application prospects for guided bone regeneration.

The Outcomes of Vertical Alveolar Bone Augmentation by Guided Bone Regeneration with Titanium Mesh: A Systematic Review

AIM

This study aimed to systematically review the published studies on vertical alveolar bone augmentation (VABA) by guided bone regeneration (GBR) with titanium mesh (TM).

BACKGROUND

Guided bone regeneration is a procedure that can be used for VABA of the alveolar ridge. Titanium mesh is used as a barrier due to its ability to maintain a space that the newly formed bone will occupy.

MATERIALS AND METHODS

A computerized literature search was conducted on the databases PubMed, SCOPUS, Science Direct, and Cochrane Library to review the published article on VABA by TM from 2011 to 2021.

REVIEW RESULTS

Eight out of 574 retrieved articles were included in the qualitative analysis, three randomized clinical trials, two prospective clinical trials, and three retrospective trials. They were assessed for risk of bias using the critical appraisal skills program checklist. Titanium mesh was utilized as a barrier in three different ways, adapted directly on the alveolar bone, bent preoperatively on three-dimensional (3D) models, and 3D-printed. Two randomized clinical trials (RCTs) reported 20.8% bone gain, while the other studies reported the means ranging from 2.56 to 4.78 mm. All studies reported TM exposure that ranged from 7.69 to 66.66%. Exposure during the four postoperative weeks led to inadequate bone regeneration. However, late exposure had no effect or caused only slight bone resorption. Early TM removal was performed in two studies, one case per each, ranging from 2.4 to 11.1%. Infection was presented in three studies, one case per each, and the percentages were 5, 11.1, and 25%.

CONCLUSION

All types of TM had exposure, which was the most common complication, but early removal was indicated only in a few cases. Titanium mesh showed reliability and efficacy as a barrier for VABA by GBR.

CLINICAL SIGNIFICANCE

By this procedure, bone height can be restored, however, meticulous follow-up is recommended for the detection and management of TM exposures.

Nano-Based Drug Delivery Systems for Periodontal Tissue Regeneration

Periodontitis is a dysbiotic biofilm-induced and host-mediated inflammatory disease of tooth supporting tissues that leads to progressive destruction of periodontal ligament and alveolar bone, thereby resulting in gingival recession, deep periodontal pockets, tooth mobility and exfoliation, and aesthetically and functionally compromised dentition. Due to the improved biopharmaceutical and pharmacokinetic properties and targeted and controlled drug release, nano-based drug delivery systems have emerged as a promising strategy for the treatment of periodontal defects, allowing for increased efficacy and safety in controlling local inflammation, establishing a regenerative microenvironment, and regaining bone and attachments. This review provides an overview of nano-based drug delivery systems and illustrates their practical applications, future prospects, and limitations in the field of periodontal tissue regeneration.

An Asymmetric Microfluidic/Chitosan Device for Sustained Drug Release in Guided Bone Regeneration Applications

One of the major challenges of guided bone regeneration (GBR) is infections caused by pathogen colonization at wound sites. In this paper, an asymmetric microfluidic/chitosan device was developed to release drugs to inhibit infections and to ensure that guided bone regeneration can be realized. The microfluidic technique was introduced into the GBR membrane for the first time, which demonstrated more controllable drug release, more flexible clinical use and had a lower cost compared with surface treatments and embedded nanoparticles. Based on the theory of diffusion and Fick’s first law, the contact area and concentration gradient were adjusted to realize sustained drug release. The standard deviation of minocycline release over 5 days was only 12.7%, which was lower than the joint effect of porous chitosan discs and nanospheres. The in vitro experiments against E. coli and Streptococcus mutans showed the excellent antibacterial performance of the device (>95%). The in vitro experiments for fibroblasts at the microfluidic side and osteoblasts at the chitosan side showed the satisfactory biocompatibility and the ability of the device to enhance bone regeneration. Therefore, this microfluidic/chitosan device is a promising therapeutic approach to prevent infection and guide bone regeneration.

Biomaterials for Periodontal Regeneration

As a widespread chronical disease, periodontitis progressively destroys tooth-supporting structures (periodontium) and eventually leads to tooth loss. Therefore, regeneration of damaged/lost periodontal tissues has been a major subject in periodontal research. During periodontal tissue regeneration, biomaterials play pivotal roles in improving the outcome of the periodontal therapy. With the advancement of biomaterial science and engineering in recent years, new biomimetic materials and scaffolding fabrication technologies have been proposed for periodontal tissue regeneration. This article summarizes recent progress in periodontal tissue regeneration from a biomaterial perspective. First, various guide tissue regeneration/guide bone regeneration membranes and grafting biomaterials for periodontal tissue regeneration are overviewed. Next, the recent development of multifunctional scaffolding biomaterials for alveolar bone/periodontal ligament/cementum regeneration is summarized. Finally, clinical care points and perspectives on the use of biomimetic scaffolding materials to reconstruct the hierarchical periodontal tissues are provided.

3D Printed and Bioprinted Membranes and Scaffolds for the Periodontal Tissue Regeneration: A Narrative Review

Numerous technologies and materials were developed with the aim of repairing and reconstructing the tissue loss in patients with periodontitis. Periodontal guided bone regeneration (GBR) and guided tissue regeneration (GTR) involves the use of a membrane which prevents epithelial cell migration, and helps to maintain the space, creating a protected area in which tissue regeneration is favored. Over the time, manufacturing procedures of such barrier membranes followed important improvements. Three-dimensional (3D) printing technology has led to major innovations in periodontal regeneration methods, using technologies such as inkjet printing, light-assisted 3D printing or micro-extrusion. Besides the 3D printing of monophasic and multi-phasic scaffolds, bioprinting and tissue engineering have emerged as innovative technologies which can change the way we see GTR and GBR.

Customized 3D-Printed Titanium Mesh Developed for an Aesthetic Zone to Regenerate a Complex Bone Defect Resulting after a Deficient Odontectomy: A Case Report

Background and Objectives: Alveolar ridge augmentation in the complex bone defect is a popular topic in implantology. Guided bone regeneration (GBR) is one of the most commonly applied methods to reconstruct alveolar bone. The application of a membrane is the fundamental principle of GBR. There are many membrane types used in oral surgery, but the advantage of the titanium mesh is the rigidity which provides space maintenance and prevents contour collapse. The smooth surface also reduces bacterial contamination. Using computer-aided design (CAD) and computer-aided manufacturing (CAM) in dentistry allows us to obtain the perfect architecture form of the mesh, which covers and protects the bone reconstruction. Case presentation: We present a surgical case of a 27-year-old female patient with severe aesthetic bone atrophy after a deficient odontectomy. Based on the GBR clinical applications, the technique consists of bone reconstruction and a customized titanium mesh application. Using mesh titanium in this case presentation was a reliable alternative to perform a lateral alveolar bone augmentation and reconstruct ridge deformities before reaching an ideal implant placement. Conclusions: According to our case report, the customized titanium mesh could be a valuable option for guided bone regeneration in aesthetic maxillary defects.