I realise this is my second post in three days, but I want to continue with the plot I've developed, and I don't want too start writing it if it turns out that the conlusion is just a bit random. So my main character ( of a sorts) was adopted by a vampire, and is later imprisoned by people for killing his mother's killers. Later on in the story, he is released by his mother, it turning out to be a plan to find out where his captors were, them being a large vampire hunting group. The whole reason his adopted parent finds him is because he has one of her fangs around his neck: this serves as a way to 'prove' that she died, but also as a way for her to find him; in my world, vampire teeth are a spoil-of-war type thing, coveted because vampires are hard to kill, and feared because a vampire can always find it's way to a missing fang. Is the whole fang tracking thing to fanciful, or, if you were reading a story with it as a mechanic, would you accept it?
Your readers will accept it fine - as long as you mention or at least foreshadow that it's a thing before your plot relies on it. If you suddenly announce it without prior mention, just as it's convenient for your character, it will probably knock your reader out of the story. You could straight-up announce that it's real (I mean, your protagonist presumably knows a lot about vampires anyway, right?), or just establish that people think it's really bad luck/a curse, and go into the real reason later.
As terobi said, it's more about how you're going to present this mechanism in the story rather than what it actually is. Be sure to mention or foreshadow it as early as possible, and you'll be fine.
As a tracking devise? I think that it's a bit too far fetched but I am into the old vampire novels. (Anne Rice rules the vamp world)! I can't stand the new ones. I get it why a hunter would collect vampire teeth, but you have to ask yourself: Isn't it a little too convenient to add an additional power like this to an already powerful being? They have to have weaknesses apart from daylight. Losing a fang used to mean great hardship for a vampire. If only it was so easy to retrieve it. The suspense needs these obstacles. Maybe try figuring out another way to track that person. I remember that in the vampire chronicles, vampire Armand gave his beloved, reporter, man-toy a necklace with a vile that contained some drops of his blood to wear. This would serve as protection from other vampires. (They would smell his old, refined blood and keep away. Like a statement saying "Bitch, he's mine. I dare you to touch him"). I don't remember very well but I don't think it served as a tracking devise, but maybe if other vampires could recognize the quality of this blood, which was quite old and rare, then maybe so could he. But on the other hand, why not recognize from the beginning the person's of interest smell of blood? Idk. Vampires have an exceptional smelling ability when it comes to their food and blood for them is like identification. So with all due respect and honesty, as an old vampire fan... Don't do it Phaidon!