A gummy smile, or excessive gingival display, is a common cosmetic concern where an unusually large amount of gum tissue is visible when a person smiles. While minor gum exposure is normal, a greater display can disrupt the balance between the lips, teeth, and gums. This condition is not related to dental health, but many individuals seek treatment to improve their smile aesthetics. Understanding the cause is necessary, as the origin dictates the most effective corrective approach.
Defining Excessive Gingival Display
A pleasing smile is characterized by the harmonious interplay between the teeth and the gums. Dental professionals generally agree that a gingival display of 1 to 2 millimeters is within the normal aesthetic range during a full smile.
Excessive gingival display is defined as the exposure of 3 to 4 millimeters or more of gum tissue. Crossing this threshold is often perceived as distracting from the teeth.
Diagnosis is based on a visual assessment of the smile’s proportions. It involves measuring the vertical distance between the upper lip’s edge and the gum line of the upper teeth. This assessment determines the amount of gingiva exposed and whether the teeth appear short relative to the gums.
Underlying Causes of a Gummy Smile
A gummy smile results from an imbalance in one of three anatomical areas: soft tissue, muscles, or underlying bone structure. Identifying the specific mechanism is the first step toward finding a solution.
Soft Tissue Causes
The soft tissue cause often involves the gum tissue failing to recede completely during dental development, known as altered passive eruption. This leaves the tooth’s crown partially covered, making teeth appear short. This issue can be compounded by gingival hyperplasia, an overgrowth of gum tissue caused by genetics, inflammation, or certain medications. Additionally, teeth that are naturally short or worn down from grinding (bruxism) can create a proportional appearance of excessive gum display.
Muscular Causes
A muscular cause, known as a hyperactive upper lip, occurs when the muscles responsible for elevating the lip are overactive. The primary muscles involved include the levator labii superioris and the levator labii superioris alaeque nasi. During a full smile, these muscles pull the upper lip significantly higher than normal, sometimes by 8 millimeters or more, exposing a larger area of the gums.
Skeletal Causes
The third major factor is a skeletal cause, referred to as Vertical Maxillary Excess (VME). This condition involves an overgrowth of the upper jawbone (maxilla) in the vertical dimension. The excess bone growth pushes the teeth and gums downward, increasing the lower third of the face and exposing excessive gingiva. VME is often diagnosed using specialized X-rays called cephalometric analysis.
Corrective Treatment Approaches
Treating a gummy smile requires a tailored approach based on the specific anatomical cause, ranging from minimally invasive options to surgery.
Soft Tissue Treatments
For cases stemming from excess gum tissue or altered passive eruption, a gingivectomy is performed. This periodontal procedure involves surgically trimming the excess gum tissue, often using a scalpel or a dental laser, to reveal the full length of the tooth crowns. If the underlying bone structure must also be addressed for stability, a crown lengthening procedure is performed. This involves removing gum tissue and recontouring the bone around the tooth roots to establish proper biological width.
Muscular Treatments
Muscular causes, such as a hyperactive upper lip, can be addressed with non-surgical or surgical options. A temporary, non-surgical solution involves Botulinum Toxin Type A (Botox) injections into the hyperactive lip elevator muscles. The toxin temporarily weakens these muscles, limiting how high the upper lip rises during a smile and reducing gum display for several months before retreatment is necessary. A more permanent solution is Lip Repositioning Surgery. In this procedure, a strip of tissue is removed from the inside of the upper lip, and the lip is sutured lower down, creating a physical restriction that limits the upward pull of the elevator muscles.
Skeletal Treatments
For the most complex cases caused by Vertical Maxillary Excess (VME), the definitive treatment is orthognathic surgery, specifically a Le Fort I osteotomy. This major surgical procedure physically repositions the maxilla upward to shorten the vertical dimension of the midface. While highly effective and permanent for VME, this is the most invasive option and is reserved for moderate to severe skeletal discrepancies.