Where can I buy dental toothpicks in Saigon?

I'm a backpacker and I need to buy dental toothpicks (these are special toothpicks which are not identical to normal restaurants toothpicks).

Where can I find those in Saigon?

I would try one of the better chemistries and without luck, even go to a western hospital, where someone can translate into Vietnamese.
The question alone should not cost an arm and a leg

Guardian
https://guardian.com.vn/en/products/dental-care