Smiling needs training. For some people, she has a smile barrier. After correcting her teeth, she still won't laugh after taking pictures of her. I often say, you go online to search the standard of smile, then touch your smile in front of the mirror and observe your smile. If you really can't laugh, you can start with chopsticks and grin with them, so that you can slowly train your smile. A charming smile can be trained. There is also a bad smile curve, which cannot be solved by training alone. You can have a dental cosmetic to meet your requirements, or go to a dentist to help you solve your problems and puzzles.