I had orthodontic treatment for quite a long time because my receding chin was severe. Because my chin was short, my tongue kept pushing on my lower teeth, so the alignment corrected early, but the teeth never really stayed fixed.
If you ask whether they are still not fixed now, I can say, "They are not fixed." I am barely maintaining alignment with a retainer.
Still, the alignment is better than before, and my mouth has moved in a little, so I am satisfied.
If you are considering orthodontics with a severe receding chin, I do recommend it because it does have the effect of reducing protruding-mouth appearance to some extent, but one thing is certain: even after orthodontic treatment ends, the receding chin itself does not improve. In other words, there is a relieving effect, but the receding chin remains a receding chin.
I was afraid of surgery, so I completely gave up on jaw surgery, and plan to just live with my receding chin, with only the occasional thought of trying filler or chin injections^^