## 1 Introduction  
Guided bone regeneration (GBR) is a surgical technique that allows the regeneration of bone at anatomical sites with vertical, horizontal, or combined defects or atrophies. Its efficacy is based on the ability to control new bone formation using a membrane barrier that prevents the settlement and proliferation of mucosal connective tissue in the bone wound and allows the colonisation of the area by totipotent osteoblastic cells from the medullary spaces [1]. It is thought that bone regeneration is achieved when osteoprogenitor cells alone repopulate the bone defect site by preventing the invasion of non-osteogenic tissue. It is estimated that up to 40% of osseointegrated implants require GBR as part of the patient's rehabilitation, and the survival rate of implants placed at augmented sites with GBR varies from 79% to 100%, with a survival rate of over 90% after at least one year of function [2]. Osteogenesis achieved by GBR consists of the same phases that characterise the physiologic process of new bone formation; therefore, between 4 and 6 months are requiredfor complete healing. During this period, the maintenance of a membrane barrier is necessary for the regeneration process to be completed: the factors related to the extent and morphology of the defect, vascularisation, and quality of the surrounding bone are critical [3]. Nonabsorbable membranes are by far the most common and widely used membranes in GBR. They include expanded polytetrafluoroethylene (e-PTFE), the non-absorbable membrane, which is considered the gold standard in many studies, unexpanded e-PTFE, rubber dam, and titanium membrane or grid [3]. The ideal GBR membrane should be sufficiently stiff to withstand the pressure of the overlying soft tissue, it should also have some degree of plasticity so that it can easily conform to the shape of the defect, and it should have an optimal degree of porosity to allow for the diffusion of fluids, oxygen, nutrients, and bioactive substances for cell growth, which is critical for bone and soft tissue regeneration, without compromising the cell-sealing property of the membrane, as soft tissue cells may migrate through the membrane and displace the defect site and inhibit the invasion and activity of bone-forming cells [2]. Specifically, rubber dam has proven effective in preventing the accumulation of plaque and the passage of bacteria, which is the case with e-PTFE [4], and in accelerating the healing of bone defects in rat calvaria after 15, 30, 60, and 120 days from the application and in achieving a higher degree of mineralisation at 60 and 120 days [5]. Unfortunately, the smooth surface of the rubber dam may present some drawbacks due to the receding of the margins over the latex and the consequent exposure of the membrane, which can produce undesirable aesthetic effects and reduce the probing depth in the newly formed tissue [4]. In recent years, tissue engineering has focused on the development of magnetic materials for bone regeneration [6; 7; 8; 9]: numerous scaffolds with magnetic properties have been tested to serve not only as a temporary matrix and to support cell growth and secretion, but also to promote osteogenesis a few days after their application thanks to the action of static magnetic fields (SMF) generated by the combination of hydroxyapatite and \(\gamma\)-Fe3O4 nanoparticles [6], hydroxyapatite and magnetite in the ratios HA /Mgn 95/5, HA /Mgn 90/10, and HA /Mgn 50/50 [7], and Fe\({}_{3}\)O\({}_{4}\)[8] with good biodegradable abilities [9]. Recently, an innovative type of implant (Cover Screw Supercharged) has been introduced, consisting of a modified neodymium-iron-boron permanent magnet (Nd\({}_{2}\)F\({}_{14}\)B) which is placed inside the device with optimal magnetic properties to accelerate the healing times of the bone around the implant and, consequently, the patient's prosthetic rehabilitation phases [10].