The trigeminal cardiac reflex (TCR) is a unique and powerful brainstem reflex that has received a great deal of research interest. Sleep bruxism (SB) is sleep disorder that affects the TCR as well as other brainstem reflexes via stimulation of the brainstem; at the level of the gasserion ganglion (GG). TCR play an important role in sleep bruxism while an exaggerated form of this reflex could be responsible for sleep disorders. This paper will discuss the unusual relationship of Trigeminal cardiac reflex – bruxism – sleep disorders.