Gummy smile
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Gummy smile, referred to in the literature as gummy smile or excessive gingival display, means an excessively large area of the maxillary gingiva visible during a full smile, according to the patient's subjective assessment. It is not an independent disease, but a feature resulting from the mutual proportions of the teeth, gums, upper lip, facial muscles, and the maxillary bone. It is most commonly assumed that exposure exceeding 2–3 mm may be perceived as excessive; however, this limit is not an absolute diagnostic criterion. A gummy smile can have a dental, gingival, muscular, or skeletal etiology, and in many individuals, several mechanisms coexist. For this reason, effective treatment requires causal diagnosis rather than solely assessing the appearance of the smile.
Gummy smile - what is it
A gummy smile is an imbalance in the proportions of the so-called red-white aesthetics, which is the relationship between the lips, gums, and teeth. In a well-harmonized smile, the lower border of the upper lip runs near the necks of the upper anterior teeth, revealing their crowns and a small band of gum. However, determining whether gum display is excessive depends not only on its height expressed in millimeters, but also on:
- the length and proportions of the clinical crowns of the teeth;
- the contour and symmetry of the gum line;
- the width of the smile;
- the position and mobility of the upper lip;
- the height of the lower third of the face;
- the patient's age, sex, and individual anatomy;
- the personal assessment of the smile's appearance.
Various threshold values are found in scientific publications. An exposure of approximately 0–2 mm of gum is most commonly considered aesthetic, whereas visibility exceeding 2–3 mm is sometimes classified as excessive [1–3]. However, these are reference values rather than criteria for diagnosing a disease. In some individuals, even greater exposure remains harmonious and causes no discomfort.
A gummy smile must be distinguished from gingival enlargement, which may be associated with inflammation, the effects of certain medications, or a systemic disease. The excessive visibility of anatomically normal gums also does not automatically indicate periodontal disease or a malocclusion.
The evaluation should include the face at rest, spontaneous and maximum smiles, incisor display, tooth proportions, and the condition of periodontal tissues. A photograph taken at a single moment may not reflect the actual dynamics of the smile, which is why video documentation is also increasingly used.
Gummy smile - where does it come from
The mechanism of a gummy smile is multifactorial. The most common causes can be divided into dentogingival, muscular, and skeletal.
Altered passive eruption (altered passive eruption) occurs when the gingival margin does not move sufficiently toward the cementoenamel junction after tooth eruption is complete. Part of the enamel remains covered by gingiva, making the clinical crowns appear short and wide. A similar presentation may be caused by gingival enlargement associated with bacterial plaque, certain medications—including selected calcium channel blockers, antiepileptic, and immunosuppressive drugs—or, less commonly, systemic disease [4].
Dentoalveolar causes include overeruption of the upper incisors, sometimes associated with a deep bite. The teeth, along with the surrounding alveolar process and gingiva, are then positioned too low relative to the lip.
The muscular component most often results from excessive elevation of the upper lip during smiling. The levator labii superioris alaeque nasi, levator labii superioris, and zygomaticus minor muscles are primarily involved in this. A hyperactive lip may move upward to a greater extent than average, despite having a normal length at rest. Another cause is an anatomically short upper lip.
The most important skeletal cause is vertical maxillary excess (vertical maxillary excess). It may be accompanied by elongation of the lower facial height, an increased interlabial gap at rest, lip incompetence, and significant incisor exposure. This mechanism may coexist with malocclusions.
In a significant proportion of patients, a gummy smile has a mixed etiology; for example, altered passive eruption coexists with a short or hyperactive lip. In such cases, treating only one component may not achieve complete correction .
Gummy smile - when is it a malocclusion, and when is it excessive muscle activity
A gummy smile is not synonymous with a malocclusion. The etiology is determined by orthodontic and periodontal examinations and soft tissue analysis. It is crucial to determine whether the excessive exposure results from the position of the bones and teeth, or from the dynamics of the upper lip.
Diagnostic feature | Dental or skeletal etiology | Muscular etiology |
|---|---|---|
Appearance at rest | Possible increased incisor exposure and incomplete lip closure | Most often normal |
Range of lip elevation | May be normal | Markedly increased |
Facial proportions | Sometimes elongated lower facial third | Usually normal |
Occlusion | Possible deep bite, incisor overeruption, or other abnormalities | Often normal |
Clinical crowns of teeth | May be normal or seemingly shortened | Usually normal |
Primary treatment | Orthodontic, periodontal, or surgical | Reduction of muscle activity or lip repositioning |
The orthodontic component may be caused by a deep bite with overeruption of the maxillary incisors, an occlusal plane disorder, or improper positioning of the anterior teeth. The skeletal component is diagnosed based on facial proportions and cephalometric examinations. In justified cases, diagnostics are supplemented with radiological imaging. However, CBCT should not be routinely performed solely for aesthetic reasons if it will not change the treatment plan.
Excessive muscle activity is indicated by a normal lip length at rest combined with its above-average elevation during a full smile. The difference in the position of the lip margin between rest and smiling is assessed, as well as the direction of gingival exposure. Exposure can be anterior, posterior, mixed, or asymmetrical.
An important element is the periodontal examination: measurement of clinical crowns, periodontal probing, localization of the cementoenamel junction, and assessment of the alveolar bone crest position. It allows distinguishing excessive muscle activity from altered passive eruption. Only the combination of data from the facial, occlusal, periodontal, and lip movement examinations enables a reliable diagnosis.
Gummy smile - how to get rid of it
A gummy smile does not require treatment if it is not the result of a disease and does not pose a problem for the patient. If correction is planned, the method should correspond to the diagnosed cause.
- Periodontal treatment is used in cases of excessive gingival tissue. It may include the treatment of inflammation, gingivectomy, or surgical crown lengthening. When the bone crest is too close to the cementoenamel junction, gingival reduction alone may be insufficient, and alveolar bone correction may be necessary. Inappropriate qualification risks recurrence, root exposure, or violation of the biological conditions of the periodontium.
- Orthodontic treatment is indicated in cases of excessive extrusion or abnormal positioning of the teeth. Intrusion, or the controlled movement of teeth upwards, can be performed using fixed appliances and skeletal anchorage. The treatment plan must take into account the levels of the gums, roots, and bone.
- Orthognathic surgery, most commonly maxillary impaction via Le Fort I osteotomy, is a causal method in severe vertical maxillary excess. It is an extensive treatment requiring comprehensive maxillofacial diagnostics and usually collaboration with an orthodontist. In selected cases of milder deformity or a hyperactive lip, surgical lip repositioning is considered; however, recurrence and temporary restriction of its mobility are possible [6].
- With a dominant muscular component, botulinum toxin type A is used, which is also available in the offer of Ambasada Urody. Injected into properly selected muscles, it temporarily inhibits the release of acetylcholine at neuromuscular junctions, reducing lip elevation. The effect is not permanent and gradually wears off. Studies indicate the effectiveness of this method in mild to moderate muscle-dependent exposure, but the quality of evidence and the uniformity of dosing protocols remain limited [7–9].
Possible adverse effects include smile asymmetry, excessive lip lengthening, difficulty with articulation, drinking, or pursing the lips. Therefore, the procedure should be performed by a doctor familiar with the anatomy of the facial muscles. Botulinum toxin does not correct excessive vertical maxillary growth, altered passive eruption, or malocclusion.
In mixed etiology, planned combination treatment can provide the best results.
