Same as Juno, Molly doesn't 'eat' the hoof she just eats the filling and sometimes has a little knaw at the sides of it. She's not able to break it off or anything, so I've never had any issues with splintering. I found it was helpful to freeze it when she was teething, the little knaw she had seemed to soothe her teeth.
I decided to fill them with wet food after I found the same thing Karen- Molly would eat the filling and then leave the hoof, so I was determined to make use of it!
And just to add- we have about 3 hooves in the house, which I keep filling again and again, so no need to buy new hooves every time