# Magnetism in Dentistry: Review and Future Perspectives
## 1 Introduction  
Various dental diseases including congenital defects, tooth loss, or trauma affect more than 3.9 billion people [1], making necessary intervention related to tissue repair or reconstruction to restore oral or maxillofacial functionalities [2, 3].  
Sustainable approaches must be developed to improve oral health and to re-direct oral health research towards a \"social determinants\" model, as evidenced by the studies conducted by [PERSON] et al. [4, 5], and for a closer collaboration-integration between general- and dental health research [6].  
According to the World Health Organization, 5-10% of healthcare budgets are represented by dental treatment costs and other costs are related to absences from work [7].  
The molecular control over cells behaviour during embryonic tooth development has gained great attention, thus generating improved awareness regarding the genesis of dental tissues as well as on teeth regeneration [8].  
Tissue engineering or tissue reconstruction/repair/regeneration represents a major interest in periodontitis, oral and maxillofacial surgery, endodontics, orthodontics, and even daily clinical practice. A vast array of techniques has been studied and developed over the years, starting from tissue transplants to more innovative and recent regenerative practices involved in the concept of tissue engineering. Recently, continuous research has been performed in the field of biomaterials and scaffolds, artificial and natural materials, genes, stem cells from dental follicle, deciduous teeth, dental pulp, periodontal ligament, salivary glands, and adipose tissue. The attention has also been focused on various growth factors involved in dental tissue repair or reconstruction [8, 9].  
Some recent studies evidenced a strong correlation between oral bacteria and neurodegenerative disorders (i.e., Alzheimer's disease (AD)). Pathogenic bacteria present in dental plaque could enter into the bloodstream and their metabolites/derived molecules pass through the blood-brain barrier (BBB), after negatively affecting its permeability, and reach the brain, promoting an increase in the levels of inflammatory cytokines, and cell and vascular adhesion molecules [10].  
In this scenario, an intriguing strategy towards the development of 3D multifunctional hybrid structure combined with active/antibacterial systems and magnetic stimulation could improve periodontal tissue prevention and treatment or repair.  
This review paper reports current innovative strategies and technological approaches in oral and maxillofacial tissue engineering. Notions dealing with the available scientific data and practical applications are reported. Starting from an introducing to tissue engineering, an overview on additive manufacturing technologies is provided. The applications of superparamagnetic iron oxide nanoparticles (SPIONs) in the biomedical field are also analysed, with a particular focus on bone and maxillocal tissue repair. We look towards magnetic fields effects and potential applications on the acceleration of orthodontic tooth movement. In this scenario, an important thought towards the development of 3D multifunctional hybrid structure combined with active/antibacterial systems and magnetic stimulation could improve periodontal tissue prevention and treatment or repair.