## 4 Discussion  
In dentistry, the stimulation with a static magnetic field (SMF) produced by permanent magnets is commonly used to accelerate tooth movements induced by orthodontic appliances [13; 14]. The application of orthodontic force in combination with an SMF allows the acceleration of root resorption, periodontal ligament space enlargement, and TRAP activity (resistant acid tartrate phosphatase, marker of osteocl activity) after 7 days of application compared to orthodontic force alone [15]. SMFs play an important role in promoting mandibular growth in class [16] malocclusions and in the conventional retention of overdentures or implants [17] because they have no adverse effects on human gingival fibroblast enzymes [18]. SMFs are, therefore, non-invasive procedures that are recommended for patients with a reduced number of teeth and poor alveolar support who require prosthetic rehabilitation. Our study aims to investigate how the use of a cofferdam can be applied as a non-absorbable membrane for GBR, which can generate a static magnetic field thanks to an Nd\({}_{2}\)F\({}_{14}\)B powder contained in it and affects cell proliferation. Unlike other membranes for GBR, such as electrically charged e-PTFE, which should be negatively charged to accelerate bone formation [19], the time-invariant static magnetic field (SMF) is generated by permanent magnets or electromagnets in which a constant direct current (continuous current) flows does not require any special properties or equipment to be easily used, and this makes this stimulation method suitable for long-term local treatments, such as dental treatments [20]. In general, with the exception of ferrite magnets, the durability of magnets is unlimited if overheating processes of the magnet at temperatures close to the Curie point of the materials they are made of (always above 300 \({}^{\circ}\)C) is avoided. Recent studies have demonstrated the existence of numerous receptors in biological systems for weak SMF in combination with alternating magnetic fields. Indeed, these stimulate the production of tumour necrosis factor (TNF) by macrophages, decrease chromatin resistance to DNAase-1, and increase protein hydrolysis both in vivo and in vitro [21]. According to a study by [PERSON] et al. (2013), static magnetic fields may be involved in the pathogenesis of atherosclerosis because they can alter LDL metabolism and the interaction of these with other molecules [22]. However, SMFs are not a therapeutic variant of EMFs in clinical practice [20; 23]. According to some in vivo studies of stimulation with permanent magnets, SMFs have a clear effect on osteogenesis, but the mechanisms of action on osteoblasts and bone metabolism are unclear [20; 23]. The physical response of the tissue is undoubtedly different from that induced by exposure to PEMFs. SMFs do not generate an electric field in the tissue, only a magnetic field [24; 25; 26], since it is not a stimulation that provides energy in any form but is a quantity of state similar to the gravitational field [27]. In this way, SMFs do not produce electric currents or vectorial changes but a biologically derived EMF with a cascade of intracellular signaling pathways [28] that directly promote the differentiation of osteoblasts and bone maturation [29]. Since the intensity of static magnetic fields depends on the mass of the permanent magnets that generate them, the achievable intensity is particularly low. However, in vitro and animal studies show that this intensity leads to an increase in the energy differentiation of cells (osteoblasts) and does not induce cell replication, making static magnetic fields safe for soft tissue [30]. From our work, we observed that during the fabrication of the magnetic dam, it was mainly observed that the adhesion of the magnetic neodymium-iron-boron powder to the latex dam did not change the properties of the dam, but the latex sheets that were bonded by heat could maintain the adhesive properties of the latex even in the cooling phase.