Bonjour Elizabeth,

"Je me brosse les dents deux fois par jour." --> I brush the teeth of mine two times per day.

The translation of "je me brosse les dents" tells us that you are brushing your teeth - not those of another person, so the possessive aspect is already clear in the grammar of the reflexive verb se brosser.

It is tricky to understand for an English speaker but this is how the French language grammar works.

Using le, la, les with body parts and clothing (definite articles)

Hope this helps to explain to you.

Bonne continuation,

Jim