I recommend dental floss.

This is the dental floss I keep in the bathroom and use. It is E-Pyeonhan Dental Floss, and I felt reassured knowing it is domestically produced. I heard that flossing is essential because brushing alone cannot completely remove plaque and debris between teeth, so I am trying to make it a habit. I have tried the type where you just cut off a piece of string, but I find this design more comfortable. There are 80 pieces in a pack, so it is very cost-effective if you buy several packs when they are on sale. If you are considering trying dental floss, I recommend giving this a try!