What is a cavity, really?

They told me I had 12 cavities and I was in shock. That part of my body could have been rotting away, dead and damaged and unbeknownst to me just baffled me. What other parts of me might be damaged? What mold am I harboring? What emotional pockets of decay might lie within the boundaries of this body I call my self? Too scary to imagine that a sharp metal object could probe my inner depths and reveal spaces of waste, festering within and poisoning the healthy, happy parts of my being. This is no longer physical. My body is not just flesh, but a curvy, cushy manifestation of my soul. If enamel from my gap-toothed mouth falls away, my soul is peeling. Whether shedding as part of a natural process or whether being ripped open by a mechanical tool, we are morphing.

Merriam-Webster online defines a cavity as

1 : an unfilled space within a mass; especially : a hollowed-out space
2 : an area of decay in a tooth : caries

What unfilled, hollowed-out spaces do we carry with us each day? How dangerous can these spaces be? How powerful? In the same way that they drilled the decay out of my mouth and replaced it with artificial stucco, can we clear out our emotional rot and replace it? And is it possible to replace with something genuine and sustainable, or is the replacement always slightly foreign, never fully part of our original selves? And which definition do we operate with when talking about emotional cavities? Is a cavity a void, or a space full of dying substance? What is a cavity, really?