The headless horseman is shown and described as having sharp-pointed, filed-down teeth; however, his skull which has been removed from his grave has normal teeth.When skull is reunited with body, the pointed teeth reappear.
At the beginning of the movie he has the filed down teeth, the skull has regular teeth, and when he comes back alive at the end, he has metal teeth. Maybe he just visits his dentist often or something.
I believe the skull does have pointed teeth.... they just aren't as sharp as they are when the Horseman is alive. I'll have to check again though, just to be sure
the skull DOES have sharp teeth. But the gums are gone, so the teeth appears more square than they actually are. And when we see the teeth of the horseman both when he is alive and when he has gotten his skull back he has his teeth slightly parted so that we can see that the teeth are pointed. When we just see the skull, the mouth is completely closed, so the points of the upper and lower teeth fitts together like a zipper, making it look like he has normal teeth.