Spanish Surgeon Dr. Angel Escudero (http://dr.escudero.com/) has a theory that pain can be reduced just by salivating! The body communicates stress in various ways; one is by creating a dry mouth when under stress. We know that stress amplifies pain perception and that reducing stress in this situation, reduces pain perception. Dr. Escudero has concluded that if we keep our mouths salivating, we can reduce pain, because the brain gets feedback that this specific stress mechanism has been eliminated. Hence no further need for pain signals.