Oral health is fundamentally linked to systemic health, with dental caries and periodontal diseases playing critical roles in the overall well-being. In Japan, a concerted effort to enhance oral health through a comprehensive initiative that started in 2024 emphasizes the prevention of oral diseases by fostering closer collaboration between medical and dental care providers. This initiative acknowledges the intricate connection between oral health and systemic conditions, including metabolic disorders and cerebrovascular and cardiovascular diseases. Recent research has underscored the significant impact of oral health on these systemic diseases, drawing attention to the interplay between oral health and the brain, as well as the complex oral-gut-brain axis. These studies offer valuable insights into how oral diseases can influence, and potentially exacerbate, systemic health issues. The review of current evidence highlights the critical need for maintaining oral health not only for the sake of dental well-being but also as an integral part of overall health. This also highlights the necessity for continued research to fully comprehend the multifaceted relationship between oral health and systemic diseases. Such understanding is paramount for developing more effective prevention, intervention, and treatment strategies, ultimately contributing to better health outcomes.