useless trivia: What Word Means: To Grind The Teeth?

Questions

according to the ancient chinese, swinging your arms cures ---------- pain?

---------- was first used as a medical treatment in 2700 b.c. by chinese emperor shen-nung?

almost ---------- million pounds of medical trash is generated each day in the u.s?

americans use over ---------- tons of aspirin a year?

during one four-year period, thomas edison obtained ---------- patents, or one every five days?