They are relevant for cavities, but the article is talking about all the other issues with our teeth, like not being aligned properly. Sugar has nothing to do with those problems, according to the article.

My dentist said sugar laden soft-drinks and sugar-laden processed food are the worst culprits.

Especially the soft drink. Apparently the acid and sugar in soda are the worst things you could put on your teeth. It's like a double whammy.

As soon as I quit soda in my 20s, my cavities stopped. My dentist said I could have as much water and beer as I wanted, but no more soda.