What is the word for an epiphany brought about through an object?

As Paola has suggested in her comment, when an object triggers a suppressed memory, it is often referred to as a madeleine moment. The term comes from a multi-volume effort by Proust titled À la recherche du temps perdu (Remembrance of Things Past or In Search of Lost Time):

In his novel, he describes an incident where he was eating tea soaked cake, and a childhood memory of eating tea soaked cake with his aunt was "revealed" to him.1 From this memory, he then proceeded to be reminded of the childhood home he was in, and even the town itself. This becomes a theme throughout In Search of Lost Time, with sensations remind Proust of previous experiences. He dubbed these Involuntary memories.

The exact passage reads thus:

No sooner had the warm liquid mixed with the crumbs touched my palate than a shudder ran through me and I stopped, intent upon the extraordinary thing that was happening to me. An exquisite pleasure had invaded my senses, something isolated, detached, with no suggestion of its origin. And at once the vicissitudes of life had become indifferent to me, its disasters innocuous, its brevity illusory – this new sensation having had on me the effect which love has of filling me with a precious essence; or rather this essence was not in me it was me. ... Whence did it come? What did it mean? How could I seize and apprehend it? ... And suddenly the memory revealed itself. The taste was that of the little piece of madeleine which on Sunday mornings at Combray (because on those mornings I did not go out before mass), when I went to say good morning to her in her bedroom, my aunt Léonie used to give me, dipping it first in her own cup of tea or tisane. The sight of the little madeleine had recalled nothing to my mind before I tasted it. And all from my cup of tea.
—Marcel Proust, In Search of Lost Time

Such moments are also described as being proustian, or colloquially, prousty. I suppose that the act itself is epiphanic in many ways as well.

While the madeleine pictured below might not trigger a childhood memory, it sure does wonders for the appetite: