The mirror of the tooth is at the incorrect distance from the origin, causing a vertex to be outside the mesh rather than inside.
Pretty much every other mirrored part of the mesh looks fine, but for some reason, this one tooth is mirroring incorrectly.
How can I fix this?
Since I don’t know how to add an attachment, here’s a DropBox link: https://www.dropbox.com/s/adqimac9gk4mwu3/Skelly236.blend?dl=0