There is precedent in 1e for this sort of thing. The Teeth of Dahlver-Nar work by knocking out your own teeth and replacing them with the rotting cavity filled artifacts that then graft irrevocably to your jaw.
Dentures are in this weird area that varies wildly between comic camp and body horror depending on how you present them.
Most obviously, magic dentures might provide you with a bite attack or a breath weapon. As body horror, they might have shapechanging effects - often irrevocable. For example, if you put the wolf dentures in your mouth, you might find yourself transformed into a werewolf.
Cursed dentures might provoke you to biting nearby comrades uncontrollably, or cause you to have a hungering for raw flesh or even human flesh, or simply say embarrassing things of their own accord in a case of magically induced Tourette's syndrome.
More light hearted, a set of magical dentures might adhere to the person's mouth - "fix it and forget it" - alleviating any need for springs or denture adhesives. Dentures of this sort, which require scarcely more enchantment than a cantrip, might be commonly available to elderly aristocrats in a high magic setting.
But in general, other than the comfort of the aged upper class in some cases, I wouldn't think that the cost of enchanting dentures would be worth the value that they'd provide, and so wouldn't expect there be much demand for magical dentures in any setting that was in any fashion trying to be believable. Such items would tend to be rare or even unique, and their creators would tend to be equally eccentric. From a balance standpoint, I'd certainly price such items as 'slotless' even if the flavor indicated that you could only wear one at a time.
