A “gummy smile” describes an appearance where a person displays an excessive amount of gum tissue above their upper teeth when smiling. While many factors can contribute, a hyperactive upper lip muscle is the most common cause treated non-surgically. Cosmetic neurotoxin injections, such as BOTOX® Cosmetic, temporarily address this muscular overactivity. By relaxing the muscles responsible for pulling the lip too high, the treatment achieves a more aesthetically balanced smile line.
The Muscular Cause of a Gummy Smile
The underlying mechanism for a hyperactive gummy smile involves muscles responsible for elevating the upper lip. The primary target for neurotoxin treatment is the Levator Labii Superioris Alaeque Nasi (LLSAN) muscle group. This muscle originates near the nose and inserts into the upper lip and the alar cartilage.
Overactivity of the LLSAN causes the upper lip to lift too high during a full smile. This exaggerated upward movement exposes the gingival tissue excessively, resulting in the characteristic gummy smile. Neurotoxin treatment works by temporarily blocking the chemical signal that tells these muscles to contract.
This temporary chemical denervation reduces the strength and range of the muscles’ contraction. By relaxing these hyperactive muscles, the upper lip is prevented from elevating as much, allowing it to cover more of the gum line when the individual smiles. The result is a reduced display of gum tissue and a more harmonious smile.
Typical Neurotoxin Unit Requirements
The dosage of a neurotoxin like BOTOX® Cosmetic for a gummy smile is low, reflecting the small size and targeted nature of the muscles involved. The common range falls between 2 to 6 units total. In most cases, the treatment involves two injection points, with the total dose divided equally between the left and right sides of the face.
A common conservative starting dose is 2 units per side, totaling 4 units of BOTOX® Cosmetic. This conservative approach is preferred because the muscles in this area are delicate, and over-treatment can lead to an undesirable aesthetic outcome, such as an altered or unnatural-looking smile. For instance, a total dose exceeding 10 units is considered a very high maximum.
Unit counts are product-specific and not interchangeable across brands. For example, the unit calculation for Dysport® is different from BOTOX® Cosmetic, often requiring two to three times the number of units to achieve a similar effect. A professional assessment is mandatory to determine the correct unit count for the specific product being used.
Variables Influencing Individual Unit Count
The specific unit count required for a successful treatment is determined by several individual factors. The most significant variable is the severity of the excessive gingival display. Patients with a more pronounced gummy smile often require a slightly higher dose to achieve the desired correction.
The inherent strength and hyperactivity of the patient’s lip elevator muscles influence the dosage. An individual with strong muscles may require a few more units than someone with milder muscle movement. Factors such as the patient’s sex can influence dosage, as male patients have larger muscle volume and may require higher units than female patients for the same effect.
The individual’s metabolism affects how quickly the body processes the neurotoxin, influencing the required dose and the longevity of the results. The chosen injection technique, such as the location of the injection points, determines the precise unit allocation. Due to these complex variables, the unit count can only be determined through a physical consultation and dynamic examination with a qualified injector.