I had protruding lips and symptoms of a retruded chin, so I got ㅋㅂ orthodontic treatment, which they said has an effect similar to double-jaw surgery. My mouth went in a bit, and because my mouth went in, it had the effect of making my jawline stand out. But it wasn't exactly dramatic. I feel like I would have gotten about this level of result even if I had done another extraction orthodontic treatment.
If I have complaints, they told me to get extractions done at another hospital and come back, which was really inconvenient, and when the wire broke, the repair cost was way too expensive. Also, they say that even after orthodontic treatment is finished, wearing a retainer for life is recommended. I wish they had clearly told me that before starting.