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Year : 2013  |  Volume : 4  |  Issue : 2  |  Page : 55-60

Gummy smile: A contemporary and multidisciplinary overview

1 Department of Orthodontics, Dental School, University of Southern Santa Catarina, (UNISUL); Tubarão - SC, Brazil
2 Department of Periodontology, Dental School, University of Southern Santa Catarina, (UNISUL); Tubarão - SC, Brazil
3 Department of Orthodontics, University of North Minas (FUNORTE/SOEBRAS), MG, Brazil
4 Department of Prosthodontics, Dental School, University of Southern Santa Catarina, (UNISUL); Tubarão - SC, Brazil

Date of Web Publication5-Jun-2013

Correspondence Address:
Jefferson Ricardo Pereira
Rua Recife 200, apto 601, Bairro Recife Tubarão, Santa Catarina
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2155-8213.113014

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The aim of this study was to elucidate the diagnosis, etiology, and therapeutic options for the treatment of gummy smile. The smile level is an imaginary line after the lower superior lip and used seems to be convex. The presence of 3 mm or grater continuous gingival band exposures to natural smile or speech performs the gummy smile. Original articles studying the diagnosis, etiology, and therapeutic alternatives for the treatment of gummy smile were searched in the Medline, Scopus, Science direct, and EBSCO host databases. Together with some example and diagnosis method was purposed. The authors conclude that the etiology is multifactorial and can be showed excessive vertical maxillary grow up, excessive labial contraction, shorter upper lip, gingival excess, and extrusion of the anterior teeth. The therapeutics alternative are often multidisciplinary, besides can be used orthognathic, plastic and periodontal surgery, and orthodontic.

Keywords: Esthetic, gummy smile, treatment

How to cite this article:
Oliveira MT, Molina GO, Furtado A, Ghizoni JS, Pereira JR. Gummy smile: A contemporary and multidisciplinary overview. Dent Hypotheses 2013;4:55-60

How to cite this URL:
Oliveira MT, Molina GO, Furtado A, Ghizoni JS, Pereira JR. Gummy smile: A contemporary and multidisciplinary overview. Dent Hypotheses [serial online] 2013 [cited 2023 Jun 5];4:55-60. Available from:

  Introduction Top

A patient's smile can express a sense of joy, success, sensuality, affection, courtesy, and show confidence and kindness. Smile is more than a form of communication; it is kind of socialization and attraction.

Dentistry is undoubtedly the health profession that deals most with smile enhancements. However, dental professionals often overlook key considerations precisely in their planning regarding smile patterns.

As suggested, part of the smile esthetics is subjective, but most is objective evaluation. The media offer a stereotyped picture of the smile that leads to smile standardization and consequently, an increased patients' demand for cosmetic dentistry.

Differently from what some dentists consider, smile harmony is determined not only by the shape, position and color of teeth, but also by the gingival tissue. The gingival margin should be as smooth as dental criteria alone. Today, both patients and dentists should be more aware of the impact of gingival upon the beauty of the person's smile.

Periodontium visibility depends on the position of the smile line, which is defined as the ratio between the upper lip and visibility of the gingival tissue and teeth. Smile level is an imaginary line that follows the lower margin of the upper lip and usually has a convex appearance. Excessive exposure of the periodontium characterizes the so-called gingival or gummy smile.

It should be emphasized that the current aesthetic standards establish a dimorphism concept influenced by age and gender. Thus, a healthy and continuous gingival margin display of around 3 mm during natural smile is desirable for women; for men, only the anterior teeth display is expected, without the continuous band of gingiva. Age influence is due to the loss of muscle tone, with a consequent lower visibility of the upper teeth and a tendency to increase lower teeth display. [1],[2]

The first step in establishing a correct diagnosis is to properly classify the gingival level, taking into consideration variables such as gender, age and periodontal health. The literature, although, abundant in this respect, is not clear and uniform; the authors present different ways of classifying the same thing. [3],[4],[5]

Once the abnormality in the smile level is determined, the establishment of the gummy smile etiology is essential. Generally, it is multifactorial interacting and is related to excessive vertical growth of maxilla, reduced length of the upper lip, excessive contraction of the upper lip and disproportionate crown length and width of anterior teeth, usually, associated with excessive gingival display, and hyperplasia or passive eruption. [6],[7],[8] Upper teeth extrusion, associated with deep bite, can also be related to the problem. [9],[10]

It is precisely the etiology of gummy smile associated with its classification that will establish a correct diagnosis, upon which all kinds of treatment will be based. In other words, the various types of treatment and their multidisciplinary nature are respected, having, however, just a single one diagnosis. Thus, this literature review seeks to establish the diagnosis, etiology and treatment alternatives available to correct gummy smile.

  Diagnosis Top

The first step in establishing a correct diagnosis and a specific plan of treatment is through a proper classification of the gingival level. Unfortunately, available ratings are irregular and use different criteria. In a classic study in this regard, examined 454 young adults and classified them into three categories according to the position of the smile line. The study used the following classification: (1) the smile line is above the cemento-enamel junction (gummy smile); (2) the smile line reveals interproximal gingiva; (3) the smile line displays less than 75% of upper anterior teeth. [3] Lately, in 1999, 733 peoples were divided as the position of the smile line into four categories: (1) low smile line, in which less than 25% of interproximal gingiva is visible and there is no margin; (2) average smile line, in which 25-75% of interproximal gingiva is visible and gingival margins of a single tooth are acceptable; (3) high smile line, in which more than 75% of interproximal gingiva and gingival margins only are visible; (4) very high smile line, which has a gingival margin of at least 2 mm continuously visible. [4]

More recently, were proposed the following: Class 1. Very high smile line (gummy smile): more than 2 mm of apical display or more than 2 mm of gingival margin to the cemento-enamel junction within sound periodontium. Class 2. High smile line: between 0 mm and 2 mm of marginal gingiva display or between 0 mm and 2 mm of the gingival margin apical to the cemento-enamel junction within sound periodontium. Class 3. Average smile line: gingival papillae are visible. Class 4. Low smile line: gingival papillae and cemento-enamel junctions are not visible. [5]

The comparison between these studies is almost impossible due to striking methodological differences. Besides the classification into different scores, the main ones include the determination of the type of smile (natural/forced) and the state of health of the periodontium. Nevertheless, there is agreement in defining gummy smile as a continuous band of gingival display of more than 3 mm, during spontaneous smile.

After all, it is extremely important to note the sexual dimorphism aspect and the influence of age on the smile line and hence, it is known that women tend to display more gingiva than men. Furthermore, older individuals tend to have a lower lip line and can be reduced by about 2 mm during spontaneous smile. They also have a significant alteration on the lower lip line and proportionally more of the lower teeth are displayed. The length of the upper lip can increase by almost 4 mm in older individuals, while the upper lip height changes less. [1],[2],[3],[11],[12]

The position and amount of teeth and gingival displayed during smile and speech, taking sexual dimorphism and the effects of aging into account, are essential, dynamic and indispensable criteria for the diagnosis and multidisciplinary planning, otherwise the patients' results are uncharacterized because of their age.

Two key points must be included during clinical/photographic examination to determine periodontium visibility. First, the dentist should look not to the marginal gingiva display (the step before smiling), but also gingival display. Secondly, the professional must consider both the natural and forced smiles when evaluating the position of the smile line. When the dentist asks a patient to smile, he or she usually takes a cautious reaction and shows a quite natural smile. However, outside the dentist's office, the patient may display a larger portion of the periodontium by forcing a smile to the maximum degree of lip contraction, thereby performing a less esthetic smile. [12] That is the reason why some authors such as recommend the use of filming as well as intense and insightful observation of the patient's expression during the initial consultation. [13]

  Etiology and Treatment Top

Several etiological factors have been proposed, which can be pedagogically divided into dental, gingival, bony, and muscular etiology. [Figure 1] shows a diagram representing the sequence proposed for the evaluation of multifactorial gummy smile. On step 1, the presence of the gummy smile is evaluated. On step 2, a clinical occlusal analysis is performed (overbite). On step 3, a gingival excess is analyzed (a. disproportionate crown width and height and gingival excess). One step 4, the bone structure is examined through cephalometric analysis. On step 5, the muscle analysis is conducted (a) lip length (in lateral pictures); (b) muscle tone (in direct front view).
Figure 1: Schematic representation of the alterations to be observed. Step 1 - Analysis of gingival exposure; Step 2 - Occlusion analysis: overbite presence; Step 3 - Gingival analysis: hyperplasic and passive eruption; Step 4 - Cephalometric analysis: labial relationship (Ricketts analysis-factors 17 and 18); bone structure (Ricketts analysis-factors 24 and 25); Step 5 - Muscle analysis - Lip length. (Cortesy of Marcelo Tomás de Oliveira)

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When excessive gingival display during smile is derived from dental etiology, there is excessive extrusion of the upper incisors that can be treated with intrusive mechanics. In this case, the problem should be limited to the anterior region.

Cases treated with intrusive mechanics based or no on mini implants, with or without periodontal surgery, were reported. [9],[10] This, when applied, was used to correct gingival and bone excess located in the anterior region caused by teeth intrusion.

[Figure 2] present, a patient with gummy smile caused by gingival grow and accentuated because orthodontic intrusive mechanic to treat excessive overbite, in other words a mix between occlusion and gingival etiology. Note the initial overbite [Figure 3] in cast models and status before [Figure 2] and after gengivectomy surgery [Figure 4].
Figure 2: Patient with maxillary growth excessive and continuous band of gingival display more than 3 mm, during spontaneous smile. (Cortesy of Marcelo Tomás de Oliveira)

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Figure 3: Initial orthodontic cast model. Observe the excessive overbite. (Cortesy of Marcelo Tomás de Oliveira)

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Figure 4: Picture after gengivectomy surgery and home bleaching. (Cortesy of Marcelo Tomás de Oliveira)

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The disproportionate height and width dimensions of the clinical crown are often indicative of problems associated with excessive gingiva, such as in cases of passive eruption, or in cases of hyperplasic growth. These orthodontic problems are difficult to solve and dentists can do very little in this respect. Nevertheless, during the treatment of associated malocclusions, careful attention must be given to multidisciplinary planning so as to establish the correct time for periodontal treatment. [7] It stands out, however, that the treatment of associated malocclusion should be conducted in a manner that does not exacerbate the problem.

The bony etiology characterized by vertical maxillary excess occurs mainly in patients with predominantly vertical growth. Clinically, there is a posterior and anterior gummy smile, even without excessive gingival. [7]

Very probably the cephalometric point "A" is positioned to offer an increase in the jaw height angulation (factor 24 of field V of the Ricketts cephalometric analysis). Factor 25, which assesses jaw rotation, must also be considered and interpreted in order to get the right diagnosis. Radiographically, there is the normal upper lip length measurement (factor 17). [14]

In the [Figure 5] the patient's cephalometric showed in the [Figure 2],[Figure 3] and [Figure 4] presenting normal factors 17, 24 e 25, justifying the no bone and lip length etiology associated to this case.
Figure 5: Initial Rickerts`s cephalometric presenting no alteration in lip length and no vertical maxillary excess. (Cortesy of Marcelo Tomás de Oliveira)

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A low interlabial occlusal plane (factor 18) can also be used, which, contrary to what was presented earlier, indicates or confirms a short upper lip. Hyperelevation of lip may be confused or even be associated with these cases and requires attention, especially when faced with patients who have no vertical growth. Nowadays, excessive vertical growth treatment implies orthognathic surgery. Despite the invasiveness of the procedure and the complications and risks imposed by the treatment, it has an extremely favorable prognosis. [6],[7],[8],[9],[10]

Although, excessive gingival exposure of dental origin, skeletal excess, or even gingival problems related to passive eruption are routinely treated in the field of orthodontics, the hypercontraction of lip levator muscles or short upper lip are not. Possibly, this is due to the fact that the primary target for most orthodontists is the hard tissue. [8]

A search of the literature reports many surgical procedures to correct gingival smile caused by muscular hyperactivity or short upper lip. However, surgical procedures may lead to a relapse and undesirable side effects such as contraction of the scar tissue. [8]

Muscle relaxation and frenectomy are most commonly indicated for short upper lip, determined by the Ricketts cephalometric analysis in factors 17 and 18 of field IV, or by profile photographs of superior Sn-St measurement.

The use of botulinum toxin (Botox) is indicated for cases of hypercontraction of the levator labii determined by the elimination of other etiologies, a minimally invasive treatment modality, which can serve as a substitute for surgery. [8],[15] This procedure has been recommended in a dosage to be applied to moderate to severe cases are 2.5 units per 0.1cc injected in a maximum of four sites. This dosage is sufficient; what varies is the number of injection sites. [8],[15] Two and four application sites are recommended for those with 3-5 mm and more than 5 mm of gingival display, respectively. The use of Botox is not recommended for those who have less than 3 mm display due to the risk of overcorrection. The need for reapplication is within 6 months, on average, ranging between 4 months and 8 months. Despite the fact that Botox overdose can cause paralysis of the target muscles, the side-effects are restricted to mild burning at the injection site. [8],[15]

The smile appearance is determined mainly by the activity of labii superioris, nasal alar elevator, zygomaticus minor and zygomaticus major muscles. These muscles determine the amount of lip elevation that occurs during the smile and therefore, would be the ones that should be disabled by the action of Botox [Figure 6]. [8]
Figure 6: Schematic representation of the muscle way. In yellow the ideal area to Botox be placed. (Cortesy of Marcelo Tomás de Oliveira)

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  Final Considerations Top

Patients' requirements are constantly increasing. Therefore, it is essential that treatment planning takes into account not only pre-determined and standardized aspects, but also smile aesthetics in a dynamic way, as well as its relationship with the patient's face.

Scientific knowledge and artistic sense is required to understand that smile aesthetics is customized and determined by teeth and gingival display in a frame called lip, which has its size determined by power and size of muscles that are fixed to a rigid bone wall.

In addition, awareness and common sense are necessary to understand that this is related to an individual who, according to current beauty standards, may be seeking not just teeth that reproduce the occlusion keys as proposed in the literature, but also a harmonic and balanced face. Thus, a diagnosis and planning with a multidisciplinary understanding is required.

  Conclusion Top

There is agreement in defining gummy smile as a continuous band of gingival display of more than 3 mm, during spontaneous smile.

The etiologic factors may occur alone or in combination. These include: skeletal problems (dental and bone); gingival disorders (passive eruption and gingival hyperplasia); and muscle problems (upper lip length and muscular hyperactivity).

Therapeutic alternatives, in accordance with the underlying etiology, are usually multidisciplinary and multifactorial. The following alternatives are presented in the literature:

  • Orthognathic surgery in cases of excessive vertical growth;
  • Orthodontic mechanics associated with intrusive mini implants in cases of overbite with extrusion of upper anterior teeth, and additional periodontal surgery to remove excessive gingival tissue and bone volume, resulting from the applied mechanics;
  • Periodontal surgery for cases of excessive gingival display or passive eruption;
  • Surgery of the muscular tissue for cases of short upper lip;
Use of Botox or surgery of the muscular tissue for cases of hypercontraction of elevator muscles of upper lip.

  References Top

1.Vig RG, Brundo GC. The kinetics of anterior tooth display. J Prosthet Dent 1978;39:502-4.  Back to cited text no. 1
2.Peck S, Peck L, Kataja M. Some vertical lineaments of lip position. Am J Orthod Dentofacial Orthop 1992;101:519-24.  Back to cited text no. 2
3.Tjan AH, Miller GD. The JG. Some esthetic factors in a smile. J Prosthet Dent 1984;51:24-8.  Back to cited text no. 3
4.Jensen J, Joss A, Lang NP. The smile line of different ethnic groups in relation to age and gender. Acta Med Dent Healv 1999;4:38-46.  Back to cited text no. 4
5.Liébart MF, Fouque-Deruelle D, Santini A, Laurent F, Monnet-Corti V, Jean-Marc G, et al. Smile line and periodontium visibility. J Periodontal Res 2004;1:17-25.  Back to cited text no. 5
6.Monaco A, Streni O, Marci MC, Marzo G, Gatto R, Giannoni M. Gummy smile: Clinical parameters useful for diagnosis and therapeutical approach. J Clin Pediatr Dent 2004;29:19-25.  Back to cited text no. 6
7.Reddy PK, Nayak DG, Uppoor A. Aesthetic crown lengthening: A report of 3 cases. Malay Dent J 2006;1:110-3.  Back to cited text no. 7
8.Hwang WS, Hur MS, Hu KS, Song WC, Koh KS, Baik HS, et al. Surface anatomy of the lip elevator muscles for the treatment of gummy smile using botulinum toxin. Angle Orthod 2009;79:70-7.  Back to cited text no. 8
9.Kim TW, Kim H, Lee SJ. Correction of deep overbite and gummy smile by using a mini-implant with a segmented wire in a growing Class II Division 2 patient. Am J Orthod Dentofacial Orthop 2006;130:676-85.  Back to cited text no. 9
10.Lin JC, Yeh CL, Liou EJ, Bowman SJ. Treatment of skeletal-origin gummy smiles with miniscrew anchorage. J Clin Orthod 2008;42:285-96.  Back to cited text no. 10
11.Ferrario VF, Sforza C, Schimitz JH, Ciusa V, Dellavia C. Digitized three-dimensional analysis of normal dento-labial relationships. Prog Orthod 2001;2:232-4.  Back to cited text no. 11
12.Van der Geld P, Oosterveld P, Kuijpers-Jagtman AM. Age-related changes of the dental aesthetic zone at rest and during spontaneous smiling and speech. Eur J Orthod 2008;30:366-73.  Back to cited text no. 12
13.Prahl-Andersen B, Ligthelm-Bakker AS, Wattel E, Nanda R. Adolescent growth changes in soft tissue profile. Am J Orthod Dentofacial Orthop 1995;107:476-83.  Back to cited text no. 13
14.Ricketts RM. Perspectives in the clinical application of cephalometrics. The first fifty years. Angle Orthod 1981;51:115-50.  Back to cited text no. 14
15.Polo M. Botulinum toxin type A in the treatment of excessive gingival display. Am J Orthod Dentofacial Orthop 2005;127:214-8.  Back to cited text no. 15


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

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