Instruct: Classify Amazon reviews into positive or negative sentiment
Query: I think my teeth got yellow-er

This is the worst toothpaste I have ever used in my life, my teeth look worse than they ever have and I'm not doing anything different except using this product. Don't get your hopes up if you buy this, regular toothpaste keeps your teeth whiter than this stuff does! I figured the word 'ultimate' would at least ensure that it helped or at least kept my teeth the same. I'm almost done with this tube and I'm going back to my trusty Crest.