A gummy smile, clinically defined as excessive gum exposure, is a condition characterized by more than 2-3 millimeters of gum tissue being visible when smiling. The following factors may contribute to this condition:
Excessive Gum Tissue (Hyperplasia)

Hyperplasia is the abnormal development of gum tissue. This condition can be caused by:

Medications: Certain medications, such as phenytoin (Dilatin) and nifedipine, can cause excessive gum growth as a side effect.
Hormonal changes: Hormonal fluctuations associated with puberty, pregnancy, or menopause can cause changes in the structure of the gums.
Poor oral hygiene: Plaque and tartar buildup can contribute to gum growth, leading to gingivitis and periodontitis.

Short Upper Lip or Overactive Smile Muscles

A short upper lip or overactive smile muscles can pull the upper lip back further than normal, exposing more of the gum. This condition can be caused by:

Genetic Factors: The short upper lip that causes a gummy smile can be inherited from your parents through genetic factors.
Hyperactive Muscles: Overactive smile muscles can pull the upper lip back further than normal, exposing more of the gum.

Vertical Maxillary Excess

Vertical maxillary excess is a condition in which the upper jawbone is excessively long and protrudes. This causes the upper teeth to appear too far forward, resulting in a gummy smile.
Dental and Skeletal Factors

Dental and skeletal problems, such as malocclusion and large teeth, can cause a gummy smile. Misaligned teeth can push the other upper teeth forward. Overly large or irregular teeth can expose more of the gum than normal.
Comprehensive Smile Analysis and Diagnosis

A comprehensive evaluation is necessary to accurately diagnose the cause of a gummy smile. This evaluation may include:

Oral examination: A detailed examination of your teeth, gums, and jaw.

Facial analysis: An evaluation of the position of your lips, teeth, and jawbones.

Imaging studies: X-rays and 3D scans may be needed to evaluate the underlying structure.

Botox Treatment for a Gummy Smile

Botox injections are a non-surgical option for treating a gummy smile caused by overactive lip muscles. By temporarily relaxing these muscles, Botox reduces the amount of gum visible when smiling. The effects of Botox are usually temporary and only last a few months.
Lip Repositioning

Lip repositioning is a surgical procedure that involves repositioning the upper lip to minimize gum exposure. The procedure can be performed using various techniques, such as sutures or lasers. Lip positioning may offer more lasting results than Botox injections.
Orthodontic Treatments

In some cases, orthodontic treatment can be used to correct a gummy smile caused by misaligned teeth. This procedure involves retracting the maxillary incisors (front teeth) to improve lip-tooth interaction. Orthodontic treatment can also help align and level the teeth, helping to achieve a more balanced and harmonious smile.