This lecture explores the powerful connection between oral health and mental wellbeing under the theme “A Happy Mouth is… A Happy Mind.” It highlights how smiles influence emotional health, how mental health affects oral hygiene behaviors, and how dental professionals play a vital role beyond restorative care. A key focus is the emerging evidence linking periodontal disease with Alzheimer’s disease, explaining the inflammatory and microbial pathways involved. The lecture emphasizes the importance of comprehensive periodontal diagnosis and early intervention—not only to preserve teeth, but to potentially protect cognitive function, dignity, and long-term brain health. Dentistry is prevention, protection, and purpose.