Yellow teeth and the airport Fork

"I was standing in the bathroom of my first college apartment trying to brush my teeth before an job interview that was happening in five minutes. When I spit into the sink, I looked up and noticed my teeth had turned this dull, dark mustard yellow, almost like old parchment. I started scrubbing them furiously with my toothbrush, but the yellow layer was soft, like damp chalk, and kept flaking off in weird little chunks into my palm. Suddenly I was sitting on a bench inside a crowded airport terminal. I had to tell the lady sitting next to me that she dropped her boarding pass, but I was so intensely self-conscious about my yellow teeth that I kept my lips pressed tight and just pointed at the floor. She gave me this deeply puzzled look and handed me a plastic fork. I looked back down at my hands and realized I was holding a small glass jar full of those yellow tooth pieces, wondering why I had saved them instead of throwing them away."