Hard to differentiate causes and consequences regarding male pattern baldness, but yes, when you bring lower teeth closer to the upper ones, bloods starts to flow better to your scalp (same when you open slightly your mouth).
I'm not an expert in anatomy and I don't now how we call this part of the head,
But as I could notice, this area seems way fuller within guys who are not bald,
that same part being mined if you look at Jason Statham head.
I have the firm belief that the cure (or the way to prevent baldness) is so simple and so "stupid" that all our complicated scientific minds are missing it,
Intuition over science dudes ...
Eskimos are never bald,
But addressing the question of cold only is not the answer (though it's a good, very good point)
It's not the whole body that needs to be colder/fresher , but the testicles ;)