I'm not trying to say that there aren't plenty of applications for small scale mechanical devices, but rather that the applications where FDM-style 3d printing would be an appropriate manufacturing process are likely to be largely biological.

Biological applications (of which tooth and bone would of course be included) are extremely well-suited for additive manufacturing because they're frequently one-offs, and therefore cannot scale, and oftentimes highly insensitive to price. Mass market products are a whole different ball game; even for applications where there isn't currently an economical manufacturing method, I'm very skeptical that there's a path where AM could be scaled out to the volumes required to sell the end component at a commercially viable cost.

To be fair though, I didn't do a good job expressing that, because I just took it for granted that it would be clear that large ratios between feature size and nozzle size are rarely economical for FDM-style AM, which isn't necessarily an obvious observation.