The appearance of too much gum tissue when smiling is known professionally as excessive gingival display, commonly called a “gummy smile.” While the ideal smile line generally reveals 1 to 2 millimeters of gum above the upper teeth, a display exceeding 3 to 4 millimeters is often considered excessive. This variance is a natural anatomical characteristic and is not typically a sign of a medical emergency. It is a common aesthetic concern that affects a significant portion of the population, particularly younger adults and women.
Anatomical Reasons for Excessive Gum Display
The underlying reasons for a gummy smile are diverse, involving the soft tissues of the lips, the position of the teeth and gums, and the structure of the jawbone. One factor relates to the mobility and length of the upper lip. Some individuals have a naturally short upper lip, defined as less than 20 millimeters in length, which does not cover the gum tissue adequately when smiling.
Alternatively, the lip may be hyperactive or hypermobile, meaning the muscles responsible for raising the lip contract too strongly during a full smile. This excessive movement is attributed to the hyperactivity of the levator labii superioris muscle, which pulls the upper lip too far superiorly, exposing more gum. These lip-related causes are often the most straightforward to diagnose and treat.
Causes also stem from the teeth and surrounding gum tissue. The condition called altered passive eruption occurs when the gum tissue fails to recede completely to its correct position as permanent teeth emerge. This leaves excess gum tissue covering the tooth crown, making the teeth appear shorter than their actual size. Similarly, dentoalveolar extrusion involves the overeruption of the maxillary incisors, where the entire tooth and its supporting bone move too far downward, resulting in a lower gum margin.
In more complex cases, the skeletal structure is the primary cause, specifically vertical maxillary excess (VME). VME is characterized by an overgrowth of the upper jawbone, or maxilla, in the vertical dimension. This skeletal issue positions the entire dentition and associated gum tissue lower on the face. Diagnosing VME requires a cephalometric analysis, a specialized X-ray measurement of the head, and frequently results in a noticeably elongated appearance of the lower facial third.
Health Status and When to Consult a Professional
For most people, a gummy smile is purely an aesthetic matter, representing a normal variation in facial anatomy. However, in certain situations, the condition can have consequences for oral health or indicate a systemic concern. When excessive gum tissue covers a large portion of the tooth, such as in altered passive eruption or gingival overgrowth, it can create difficulties with proper oral hygiene.
This excess tissue makes it harder to effectively brush and floss near the gumline, increasing the risk for plaque retention and periodontal disease. In some instances, the gum enlargement, known as gingival hyperplasia, is a side effect of certain medications. Drug classes associated with this overgrowth include anticonvulsants, immunosuppressants like cyclosporine, and calcium channel blockers.
If the gumline appears suddenly enlarged, is bleeding, or seems noticeably uneven, consult a dental professional. These symptoms may suggest inflammation from poor hygiene, an underlying systemic condition, or a reaction to a new medication. A comprehensive dental examination is necessary to distinguish between a purely cosmetic anatomical variation and a condition requiring medical or periodontal management.
Professional Solutions for Correcting a Gummy Smile
Treatment for a gummy smile depends on accurately identifying the underlying cause, which dictates the most effective intervention. For cases caused by a hyperactive upper lip muscle, non-surgical methods are often the first approach. Botulinum toxin injections (Botox) can temporarily relax the hyperactive levator labii superioris muscle. This procedure limits the upward movement of the lip during smiling, with results typically lasting three to six months before requiring a repeat treatment.
When the cause is related to an overgrowth of gum tissue, a minor surgical procedure is usually recommended. A gingivectomy, or laser gum contouring, removes the excess soft tissue to expose the full height of the tooth crown. If the problem is altered passive eruption, a crown lengthening procedure is performed. This involves removing gum tissue and precisely reshaping a small amount of the underlying bone to ensure the gum line is stable and permanent.
For patients with a short or hypermobile lip seeking a more permanent solution than injectables, lip repositioning surgery may be an option. This procedure involves removing a strip of tissue from the inside of the upper lip and suturing the lip in a lower position, restricting its upward movement. The most involved treatment is reserved for skeletal issues like severe vertical maxillary excess. This requires orthognathic surgery, a major procedure performed by an oral surgeon to reposition the entire upper jawbone higher into the skull, providing a permanent correction of the skeletal structure.