My feeling would be that redirecting to other sensory activities ("go have a drink at the water fountain, then come back" or "here, have some gum") is better at school than chewelry (which seems to me almost as stigmatizing as having an icky shirt, and yes BTDT).

The only chewy toy I'd find marginally OK with teacher approval would be the pencil topper... even then, kind of disruptive...

DeeDee