(Concern) I am undergoing orthodontic treatment with a retainer, but my teeth keep spreading apart.

I had orthodontic treatment six years ago and am wearing a retainer inside.

However, lately, the middle part between the upper and lower teeth keeps opening up.

As a result, I could see a little bit of the metal of the internal retention device from the outside.

I believe that if I wear the retainer, my teeth shouldn't open up further, but it seems like they are continuing to shift. I'm wondering if I need to start wearing the retainer again.

I wasn't sure whether I should go to another hospital or go back to the hospital I was considering and get a second opinion.

If it continues like this, I think it will keep opening up and more food will get stuck, so I'm very uncomfortable right now and I'm really worried about what to do.