Resorbable magnesium metal membrane for sinus lift procedures: a case series.

BACKGROUND: The purpose of this case series was to demonstrate the use of a magnesium membrane for repairing the perforated membrane in both direct and indirect approaches, as well as its application in instances where there has been a tear of the Schneiderian membrane. CASE PRESENTATION: The case series included four individual cases, each demonstrating the application of a magnesium membrane followed by bone augmentation using a mixture of xenograft and allograft material in the sinus cavity. In the first three cases, rupture of Schneiderian membrane occurred as a result of tooth extraction, positioning of the dental implant, or as a complication during the procedure. In the fourth case, Schneiderian membrane was perforated as a result of the need to aspirate a polyp in the maxillary sinus. In case one, 10 mm of newly formed bone is visible four months after graft placement. Other cases showed between 15 and 20 mm of newly formed alveolar bone. No residual magnesium membrane was seen on clinical inspection. The vertical and horizontal augmentations proved stable and the dental implants were placed in the previously grafted sites. CONCLUSION: Within the limitations of this case series, postoperative clinical examination, and panoramic and CBCT images demonstrated that resorbable magnesium membrane is a viable material for sinus lift and Schneiderian membrane repair. The case series showed successful healing and formation of new alveolar bone with separation of the oral cavity and maxillary sinus in four patients.

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.

Possible Applications for a Biodegradable Magnesium Membrane in Alveolar Ridge Augmentation-Retrospective Case Report with Two Years of Follow-Up.

Background and Objectives: A rigid, resorbable magnesium membrane was recently developed, combining the advantages of resorbable and non-resorbable membranes. Our aim was to describe the application of this membrane for guided bone regeneration (GBR). Materials and Methods: This case report described the treatment and 3D evaluation of two cases utilizing a resorbable magnesium barrier membrane. In Case #1, GBR was performed with a bilayer tunnel flap. The magnesium barrier was placed fixed subperiosteally through remote vertical incisions. In Case #2, GBR was performed using a split-thickness flap design. Volumetric and linear hard tissue alterations were assessed by 3D cone-beam computed tomography subtraction analysis, as well as with conventional intraoral radiography. Results: Case #1 showed a volumetric hard tissue gain of 0.12 cm3, whereas Case #2 presented a 0.36 cm3 hard tissue gain. No marginal peri-implant hard tissue loss could be detected at the two-year follow-up. Conclusions: The application of conventional resorbable collagen membranes would be difficult in either of the cases presented. However, the rigid structure of the magnesium membrane allowed for the limitations of conventional resorbable membranes to be overcome.

Evaluation between Biodegradable Magnesium Metal GBR Membrane and Bovine Graft with or without Hyaluronate.

Bone substitutes and barrier membranes are widely used in dental regeneration procedures. New materials are constantly being developed to provide the most optimal surgical outcomes. One of these developments is the addition of hyaluronate (HA) to the bovine bone graft, which has beneficial wound healing and handling properties. However, an acidic environment that is potentially produced by the HA is known to increase the degradation of magnesium metal. The aim of this study was to evaluate the potential risk for the addition of HA to the bovine bone graft on the degradation rate and hence the efficacy of a new biodegradable magnesium metal GBR membrane. pH and conductivity measurements were made in vitro for samples placed in phosphate-buffered solutions. These in vitro tests showed that the combination of the bovine graft with HA resulted in an alkaline environment for the concentrations that were used. The combination was also tested in a clinical setting. The use of the magnesium metal membrane in combination with the tested grafting materials achieved successful treatment in these patients and no adverse effects were observed in vivo for regenerative treatments with or without HA. Magnesium based biodegradable GBR membranes can be safely used in combination with bovine graft with or without hyaluronate.

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.

Concussed Neural Signature is Substantially Different than Fatigue Neural Signature in Non-concussed Controls.

Traumatic brain injuries can result in short-lived and long-lasting neurological impairment. Identifying the correct recovery timeframe is challenging, as balance-based metrics may be negatively impacted if testing is performed soon after exercise. Thirty-two healthy controls and seventeen concussed individuals performed a series of balance challenges, including virtual reality optical flow perturbation. The control group completed a backpacking protocol to induce moderate fatigue. Concussed participants had lower spectral power in the motor cortex and central sulcus when compared to fatigued controls. Moreover, concussed participants experienced a decrease in overall theta band spectral power while fatigued controls showed an increase in theta band spectral power. This neural signature may be useful to distinguish between concussed and non-concussed fatigued participants in future assessments.

Application of Biodegradable Magnesium Membrane Shield Technique for Immediate Dentoalveolar Bone Regeneration.

For the first time, the clinical application of the first CE registered magnesium membrane is reported. Due to the material characteristics of magnesium metal, new treatment methodologies become possible. This has led to the development of a new technique: the magnesium membrane shield technique, used to rebuild the buccal or palatal walls of compromised extraction sockets. Four clinical cases are reported, demonstrating the handling options of this new technique for providing a successful regenerative outcome. Using the technique, immediate implant placement is possible with a provisional implant in the aesthetic zone. It can also be used for rebuilding both the buccal and palatal walls simultaneously. For instances where additional mechanical support is required, the membrane can be bent into a double layer, which additionally provides a rounder edge for interfacing with the soft tissue. In all reported clinical cases, there was a good bone tissue regeneration and soft tissue healing. In some instances, the new bone had formed a thick cortical bone visible in cone beam computed tomography (CBCT) radiographs of the regenerated sites, which is known to be remodeled in the post treatment period. Overall, the magnesium membrane shield technique is presented as an alternative treatment option for compromised extraction sockets.

Biodegradation of a Magnesium Alloy Fixation Screw Used in a Guided Bone Regeneration Model in Beagle Dogs.

Nowadays, the most commonly used fixation systems are non-resorbable, but new resorbable magnesium alloy fixation screws have been introduced recently. Therefore, the aim of this study was to compare the magnesium fixation screw and the commonly used non-resorbable titanium screw in an animal model. Four 3-wall defect sites were covered with collagen membranes in the mandible of twenty beagle dogs (two sites on the left and two on the right). Each membrane was fixed with either four magnesium screws or four titanium screws. Post-operative follow-up revealed the expected observations such as transient inflammation and pain. Both groups showed a good healing response, with no differences between groups. Micro-CT analysis showed no significant difference between groups in terms of BV/TV or soft tissue volume. The void volume in the magnesium fixation screw group continued to decrease on average between the different timepoints, but not significantly. Furthermore, a gradual progression of the degradation process of the magnesium screws was observed in the same group. Magnesium screws and titanium screws showed equal performance in tissue regeneration according to GBR principles. An additional advantage of magnesium screws is their resorbable nature, which eliminates the need for a second surgical step to remove the screws.

Analysis of a Pure Magnesium Membrane Degradation Process and Its Functionality When Used in a Guided Bone Regeneration Model in Beagle Dogs.

For the surgical technique of guided bone regeneration (GBR), the choice of available barrier membranes has until recently not included an option that is mechanically strong, durable, synthetic and resorbable. The most commonly used resorbable membranes are made from collagen, which are restricted in their mechanical strength. The purpose of this study is to evaluate the degradation and regeneration potential of a magnesium membrane compared to a collagen membrane. In eighteen beagle dogs, experimental bone defects were filled with bovine xenograft and covered with either a magnesium membrane or collagen membrane. The health status of the animals was regularly monitored and recorded. Following sacrifice, the hemimandibles were prepared for micro-CT (µ-CT) analysis. Complications during healing were observed in both groups, but ultimately, the regenerative outcome was similar between groups. The µ-CT parameters showed comparable results in both groups in terms of new bone formation at all four time points. In addition, the µ-CT analysis showed that the greatest degradation of the magnesium membranes occurred between 1 and 8 weeks and continued until week 16. The proportion of new bone within the defect site was similar for both treatment groups, indicating the potential for the magnesium membrane to be used as a viable alternative to collagen membranes. Overall, the new magnesium membrane is a functional and safe membrane for the treatment of defects according to the principles of GBR.

Biodegradable magnesium barrier membrane used for guided bone regeneration in dental surgery.

Barrier membranes are commonly used as part of the dental surgical technique guided bone regeneration (GBR) and are often made of resorbable collagen or non-resorbable materials such as PTFE. While collagen membranes do not provide sufficient mechanical protection of the covered bone defect, titanium reinforced membranes and non-resorbable membranes need to be removed in a second surgery. Thus, biodegradable GBR membranes made of pure magnesium might be an alternative. In this study a biodegradable pure magnesium (99.95%) membrane has been proven to have all of the necessary requirements for an optimal regenerative outcome from both a mechanical and biological perspective. After implantation, the magnesium membrane separates the regenerating bone from the overlying, faster proliferating soft tissue. During the initial healing period, the membrane maintained a barrier function and space provision, whilst retaining the positioning of the bone graft material within the defect space. As the magnesium metal corroded, it formed a salty corrosion layer and local gas cavities, both of which extended the functional lifespan of the membrane barrier capabilities. During the resorption of the magnesium metal and magnesium salts, it was observed that the membrane became surrounded and then replaced by new bone. After the membrane had completely resorbed, only healthy tissue remained. The in vivo performance study demonstrated that the magnesium membrane has a comparable healing response and tissue regeneration to that of a resorbable collagen membrane. Overall, the magnesium membrane demonstrated all of the ideal qualities for a barrier membrane used in GBR treatment.

Biodegradable magnesium fixation screw for barrier membranes used in guided bone regeneration.

An ideal fixation system for guided bone (GBR) regeneration in oral surgery must fulfil several criteria that includes the provision of adequate mechanical fixation, complete resorption when no longer needed, complete replacement by bone, as well as be biocompatible and have a good clinical manageability. For the first time, a biodegradable magnesium fixation screw made of the magnesium alloy WZM211 with a MgF2 coating has been designed and tested to fulfill these criteria. Adequate mechanical fixation was shown for the magnesium fixation screw in several benchtop tests that directly compared the magnesium fixation screw with an equivalent polymeric resorbable device. Results demonstrated slightly superior mechanical properties of the magnesium device in comparison to the polymeric device even after 4 weeks of degradation. Biocompatibility of the magnesium fixation screw was demonstrated in several in vitro and in vivo tests. Degradation of the magnesium screw was investigated in in vitro and in vivo tests, where it was found that the screw is resorbed slowly and completely after 52 weeks, providing adequate fixation in the early critical healing phase. Overall, the magnesium fixation screw demonstrates all of the key properties required for an ideal fixation screw of membranes used in guided bone regeneration (GBR) surgeries.

Biocompatibility Analyses of HF-Passivated Magnesium Screws for Guided Bone Regeneration (GBR).

Background: Magnesium (Mg) is one of the most promising materials for human use in surgery due to material characteristics such as its elastic modulus as well as its resorbable and regenerative properties. In this study, HF-coated and uncoated novel bioresorbable magnesium fixation screws for maxillofacial and dental surgical applications were investigated in vitro and in vivo to evaluate the biocompatibility of the HF coating. Methods: Mg alloy screws that had either undergone a surface treatment with hydrofluoric-acid (HF) or left untreated were investigated. In vitro investigation included XTT, BrdU and LDH in accordance with the DIN ISO 10993-5/-12. In vivo, the screws were implanted into the tibia of rabbits. After 3 and 6 weeks, degradation, local tissue reactions and bony integration were analyzed histopathologically and histomorphometrically. Additionally, SEM/EDX analysis and synchrotron phase-contrast microtomography (µCT) measurements were conducted. The in vitro analyses revealed that the Mg screws are cytocompatible, with improved results when the surface had been passivated with HF. In vivo, the HF-treated Mg screws implanted showed a reduction in gas formation, slower biodegradation and a better bony integration in comparison to the untreated Mg screws. Histopathologically, the HF-passivated screws induced a layer of macrophages as part of its biodegradation process, whereas the untreated screws caused a slight fibrous tissue reaction. SEM/EDX analysis showed that both screws formed a similar layer of calcium phosphates on their surfaces and were surrounded by bone. Furthermore, the µCT revealed the presence of a metallic core of the screws, a faster absorbing corrosion front and a slow absorbing region of corroded magnesium. Conclusions: Overall, the HF-passivated Mg fixation screws showed significantly better biocompatibility in vitro and in vivo compared to the untreated screws.

Ex Vivo and In Vivo Analyses of Novel 3D-Printed Bone Substitute Scaffolds Incorporating Biphasic Calcium Phosphate Granules for Bone Regeneration.

(1) Background: The aim of this study was examining the ex vivo and in vivo properties of a composite made from polycaprolactone (PCL) and biphasic calcium phosphate (BCP) (synprint, ScientiFY GmbH) fabricated via fused deposition modelling (FDM); (2) Methods: Scaffolds were tested ex vivo for their mechanical properties using porous and solid designs. Subcutaneous implantation model analyzed the biocompatibility of PCL + BCP and PCL scaffolds. Calvaria implantation model analyzed the osteoconductive properties of PCL and PCL + BCP scaffolds compared to BCP as control group. Established histological, histopathological and histomorphometrical methods were performed to evaluate new bone formation.; (3) Results Mechanical testing demonstrated no significant differences between PCL and PCL + BCP for both designs. Similar biocompatibility was observed subcutaneously for PCL and PCL + BCP scaffolds. In the calvaria model, new bone formation was observed for all groups with largest new bone formation in the BCP group, followed by the PCL + BCP group, and the PCL group. This finding was influenced by the initial volume of biomaterial implanted and remaining volume after 90 days. All materials showed osteoconductive properties and PCL + BCP tailored the tissue responses towards higher cellular biodegradability. Moreover, this material combination led to a reduced swelling in PCL + BCP; (4) Conclusions: Altogether, the results show that the newly developed composite is biocompatible and leads to successful osteoconductive bone regeneration. The new biomaterial combines the structural stability provided by PCL with bioactive characteristics of BCP-based BSM. 3D-printed BSM provides an integration behavior in accordance with the concept of guided bone regeneration (GBR) by directing new bone growth for proper function and restoration.

Material Properties of the Medial Elbow During Passive Valgus and Self-Initiated Varus Torques.

Shear wave elastography imaging of the ulnar collateral ligament (UCL) is used to help understand changes in material properties of the ligament. Ensuring that the wrist flexors are relaxed is essential as muscle contractions can alter the alignment of the medial elbow. The purpose of this study was to determine how the structural and material properties of the medial elbow respond to various elbow torques. The medial elbows of 20 healthy adults, free from upper extremity disorders, were imaged in 3 of the following torque conditions: (1) neutral relaxed, (2) passive valgus, and (3) active varus. Structural properties (ulnohumeral gap and UCL length) using B-mode and material properties (UCL and flexor muscle stiffness) using shear wave were measured. Passive valgus torque opened the ulnohumeral gap (P < .001), and increased UCL (P < .001) and wrist flexor stiffness (P = .001), compared with the neutral condition. Under an active varus contraction, the gap returned back to the neutral position, but UCL (P < .008) and wrist flexor stiffness (P < .004) remained elevated compared with neutral, meaning low-intensity torques can influence structural and material properties of the medial elbow. Therefore, effort should be taken to minimize muscle activation during imaging in order to accurately measure medial elbow properties.

Oculomotor Behavior Predict Professional Cricket Batting and Bowling Performance.

Importance: A new, shorter version of cricket was introduced recently (Twenty20; T20). Since its inception, T20 cricket has rapidly become a popular and exciting format of cricket. However, there is little understanding of factors such as visual-motor control that influence expert performance. Objective: The purpose of this project is to determine if a series of oculomotor measures can predict batting and bowling performance in professional cricket players. Design: This study used a cross-sectional design. Each participant took part in a suite of eye-tracking tests to measure oculomotor behavior compared to their performance data. Participants: This study used a sample of 59 male T20 league professional cricket players (30 Bowlers and 29 Batsman). Results: One-way univariate analyses of variance examined the differences in oculomotor behavior between batsman and bowlers. A series of multiple regression analyses was conducted to evaluate how well the visual variables predict bowling and batting performance variables. Results demonstrate that several oculomotor eye tracking measures were good predictors of run performance and strike rate, including sports total score, sports on-field score, and sports functional score. Likewise, several of the same metrics predicted Runs and Wicket performance for bowlers. Overall, results provided further validation to a growing body of literature supporting the use of eye-tracking technology in performance evaluation.

Physical Activity Coparticipation Among Parent-Young-Child Dyads.

PURPOSE: This study examined patterns of physical activity coparticipation among parent-child (2-5 y) dyads. METHOD: The dyads (N = 47; 51% mother-child) each wore a Bluetooth-enabled accelerometer for 8 days to measure physical activity and physical activity coparticipation. The parents completed demographic and self-reported family physical activity questionnaires. RESULTS: The parent-child dyads spent 145 (79) minutes per day in-proximity according to the Bluetooth-enabled accelerometers. The majority (90%) of parent-child in-proximity time was spent with the parent and child engaged in some combination of sedentary or light activities. Child light, moderate, and vigorous physical activity was not associated with parent light (P = .12) or moderate to vigorous physical activity (P = .45), but was positively associated with parent-child in-proximity active minutes (light, moderate, and vigorous) (P < .01). Children in the highest tertile of parent-child physical activity coparticipation engaged in more daily moderate to vigorous physical activity compared with children in the lowest tertile (72.7 vs 50.3 min). There was a positive, statistically significant association between self-reported and objective measures of physical activity coparticipation (r = .47, P = .001). CONCLUSION: Children who engaged in the most physical activity with their parent had the highest moderate to vigorous physical activity. Future studies should continue to provide contextual information about how parents and children spend their time together to improve family-based physical activity interventions.

Anterior-Posterior Balance Perturbation Protocol Using Lifelike Virtual Reality Environment.

Virtual reality (VR) paradigms have proved to be a valid method to challenge and perturb balance. There is little consensus in the literature on the best protocol design to perturb balance and induce postural sway. Current VR interventions still lack a well-defined standardized metric to generate a virtual environment that can perturb balance in an efficacious, lifelike, and repeatable manner. The objective of this study was to investigate different configurations of amplitude and frequency in an anterior-posterior translation VR environment, that is, lifelike and scaled. Thirteen young adults with no conditions affecting balance were recruited. Balance was challenged by anterior-posterior sinusoidal movement of the lab image within the VR headset. Four different amplitudes of the sinusoidal movement were tested: 1, 5, 10, and 20 cm, with each amplitude being presented at 2 test frequencies : 0.5 and 0.25 Hz. Mean center of pressure velocity was significantly greater than baseline at 0.5 Hz and amplitudes of 10 and 20 cm. Mean center of pressure at approximate entropy was greater than baseline at 0.5 Hz and amplitude of 20 cm. The results suggest that sinusoidal movement of a realistic VR environment produces altered balance compared with baseline quiet standing, but only under specific movement parameters.

Implantation of an Injectable Bone Substitute Material Enables Integration Following the Principles of Guided Bone Regeneration.

BACKGROUND/AIM: The present study investigates the in vivo tissue reaction and the integration behavior of an injectable bone substitute material (IBS) composed of a water-based gel combined with nano hydroxyapatite particles and biphasic calcium phosphate granules. The results of the IBS were compared to biphasic bone substitute granules (BBSM) of the same chemical composition. MATERIALS AND METHODS: The subcutaneous implantation model in 40 female 5-week-old CD-1 mice up to 60 days after implantation was used for conduction of the in vivo experiments. Moreover, established histological, histopathological and histomorphometrical methods were applied. RESULTS: The results showed that the IBS was gradually invaded by cells and complex tissue elements. Thus, the implant bed could be distinguished in two areas, i.e. an outer and inner region. While the outer region started to interact with the peri-implant tissue by evoking multinucleated giant cells and at earlier time points by undergoing a continuous high vascularization, the inner part was free of peri-implant cells for at least 30 days, starting to undergo a similar tissue reaction at a later time point. The bone substitute granules allowed for a fast tissue influx between the interspaces of the granules starting at day 10. While the vessel density did not differ in both groups up to the end of the study, the amount of vascularization was significantly higher over the entire observation period in the BBSM group. Moreover, the amount of biomaterial-associated multinucleated giant cells (BMGCs) was significantly higher in the IBS group in the period of between 15 to 30 days after implantation, while comparable BMGC numbers were found in both groups towards the end of the study. CONCLUSION: IBS can build a barrier-like structure that is able to control the soft tissue influx into the central regions of the implantation bed, which could not be observed in other bone substitute granules of the same chemical composition. This directed integration behavior is assumed to be in accordance with the concept of Guided Bone Regeneration (GBR). Furthermore, BMGCs can significantly influence the process of angiogenesis within an implant bed of a biomaterial but not the maturity of blood vessels.

Practice day may be unnecessary prior to testing knee extensor strength in young healthy adults.

A practice session is common prior to strength testing. However, the benefits of practice have not been previously reported. The purpose of this study was to determine the effect of a practice session on peak torque, mean torque and between trial variability across three test days. We hypothesized that peak and mean torque would be higher and less variable the second and third test days than the first. Twenty-five healthy, young participants completed 3 maximal voluntary isometric and isokinetic knee extensions on three separate days. No difference in isometric torque was found between days 1 and 2, but there was a significant decrease in isokinetic torque (8.45 Nm). There was a significant decrease in both mean isometric and isokinetic torque from day 1 to day 3 (12.67 and 13.59 Nm). Contrary to our hypothesis, no benefit from a practice session was found. Healthy, young adults are able to produce peak knee extensor torques on the first day of testing and do not demonstrate any benefit from additional testing. Thus, a practice day preceding isometric and isokinetic knee extensor strength testing may not be necessary when testing healthy, young participants, and may, in fact, negatively impact subsequent strength measurements.

An introduction to bone tissue engineering.

Bone tissue has the capability to regenerate itself; however, defects of a critical size prevent the bone from regenerating and require additional support. To aid regeneration, bone scaffolds created out of autologous or allograft bone can be used, yet these produce problems such as fast degradation rates, reduced bioactivity, donor site morbidity or the risk of pathogen transmission. The development of bone tissue engineering has been used to create functional alternatives to regenerate bone. This can be achieved by producing bone tissue scaffolds that induce osteoconduction and integration, provide mechanical stability, and either integrate into the bone structure or degrade and are excreted by the body. A range of different biomaterials have been used to this end, each with their own advantages and disadvantages. This review will introduce the requirements of bone tissue engineering, beginning with the regeneration process of bone before exploring the requirements of bone tissue scaffolds. Aspects covered include the manufacturing process as well as the different materials used and the incorporation of bioactive molecules, growth factors and cells.