Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Hockey Puck

My dentist suggested I buy a mouth guardfrom him. I didn't want to pay $300, so Itried the Day/Night Mouth Guard Kit. Iwas able to mold it to my bite and it stayedin place. There is no way to regulatethe size of the gap between your upper andlower teeth. I couldn't get any sleep becauseit felt like I had a hockey puck in my mouth.I re-heated the guard and tried again and hadthe same result. I tried one other guardand didn't like it either. I finally bought theguard from the dentist, and it is great. Thedentist took molds of my teeth, determined thespacing between upper and lower teeth, and grindeddown the guard to make sure that all my lower teethhit it at the same time when I bit down. It'sno big deal to wear it. I get great sleep, andI don't even notice it until morning.