Why does my entire upper gum come out when I laugh? What caused it?

I went to the dentist. I was dissatisfied with my grin for a long time. Once I washed my teeth and asked me a grinning question directly, so the doctor took a dental film for me. The doctor said that there are many reasons for grinning, so if you want to know how to remedy it, you must first know why you laugh and why your gums are exposed. One is the problem of dental bone, and you need to take a film to know whether orthodontics is needed. The doctor said that my orthodontic effect is not great, and I don't know the details. Another problem is the gums, that is, the gums grow too much, and the teeth that should have been exposed are covered by the gums. I belong to this kind, and my teeth are very short. The solution is to cut off excess gums. This picture is easier to understand.

I wonder if your teeth are the same as mine. Let's go to the dentist first.