Most DEFINITELY a fetish, though it's quite limited to orthodontic hardware. Braces, tongue cribs, rubber bands, expanders, powerchains, and ESPECIALLY Headgear. If it's orthodontic, I'm probably going to like it. For me, the fascination definitely started in middle school, though like most, my interest in the orthodontic likely resulted from some kind of childhood "experience" I'm not all aware of. I'll be completely honest: If I knew the experience, I would say. Who knows, maybe I'll figure it out someday.
Stay safe, and Much Love <3