Yes in the old days before toothpaste and other teeth cleaning products the Romans did use Urine to clean and brush their teeth with.
They mostly used their own urine even though it sounds gross and I certainly would not do it myself but Romans did indeed use urine for brushing teeth with.
The urine turns into ammonia when exposed to air and makes for a good cleaning product for teeth to help whiten them and keep them white.
But there are many other options today that are healthier and less gross so I would not recommend brushing your teeth with urine.
I've also read that the Romans used Feces or poop to brush teeth with as well.