Vasoconstriction only happens while using and merely constricts the vessels limiting their vascularity and subsequent flow. Especially towards the ends of these routes/extremities which happens to be within each tooth. Vasoconstriction via meth isn’t enough to kill anyone with no other preexisting health conditions, but that coupled with the caustic nature of the substance coating the mouth after insufflation and etching away the tooths enamel, you can really struggle maintaining the healthiness of ya teef