Part of mesh not casting shadows onto everything else. Why??

I have attached a screenshot. I have a head model with multiple materials… and i noticed that only the part of the mesh that has teeth material is casting shadows… The rest of the materials are not casting shadows… I tried switching everything to the teeth material and it remains that teeth are the only thing casting shadows in this mesh… why would that be???

Never mind… in the mesh properties… some of the elements had cast shadows checked off for some reason…