It should be a prominent maxilla, but that's not the whole reason for your problem.

Too much gum exposure when laughing may be caused by prominent maxillary development, but it may also be caused by prominent alveolar bone. In this case, the alveolar bone can be trimmed to solve this problem.

It may also be caused by the underdeveloped upper lip and the short upper lip. It may also be caused by several factors and comprehensive factors.