The 'Dental Plan / Lisa Needs Braces' meme originates from the 1993 episode of The Simpsons titled 'Last Exit to Springfield.' In the scene, Lenny reminds Homer about their dental plan, which triggers a repetitive loop in Homer's brain of Marge saying 'Lisa needs braces.' The sequence perfectly captures the slow process of a realization dawning on someone. In internet culture, it is used to represent obsessive thoughts, the cyclic nature of bureaucracy, or any situation where two related facts are stuck in a feedback loop inside someone's head.