This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sleep disorders and eating disorders, Subject name: Psychiatry
Bruxism is 
Select and explain. 
A. Walking during sleep, B. Nocturnal enuresis, C. Grinding of teeth during sleep, D. Sleep apnoea
C: Grinding of teeth during sleep
Answer: C: Grinding of teeth during sleep 
Explanation: Bruxism (teeth-grinding): The patient has an involuntary and forceful grinding of teeth during sleep. Though the bed paner repos loud sounds produced by grinding of teeth and destruction of the tooth enamel is obvious, the patient remains completely unaware of the episode(s). Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no. 140