A gummy smile occurs when more of the gums are visible when you smile, causing the teeth to look abnormally small in comparison. A gummy smile is solved with a cosmetic dentistry treatment such as laser gum reshaping or crown lengthening. These are the factors that cause a gummy smile:
Teeth that are worn away will naturally look smaller compared to the gums.
Heredity can also play a role in having smaller-looking teeth, making the gums look bigger.
Short upper lip
A short upper lip or a high lip line can make the gums and teeth always visible.
Teeth not fully erupted from the gums
Teeth that have not completely erupted from the gums can look unnaturally small.