Excessive gingival display or “gummy smile” is a growing concern to dental patients and often considered detrimental to an esthetic smile. Gingival display of more than 4 mm of gingiva is considered by many to be unattractive. The cause of the gummy smile can be multifactorial and must be accurately diagnosed to render appropriate treatment. Factors that contribute to the gummy smile include altered passive eruption, lip length, lip hypermobility, incisal wear/crown length, and vertical maxillary excess and gingival hyperplasia. The purpose of this article is to review the etiology, diagnosis, and surgical approaches in treating the gummy smile.
Excessive gingival display is a common esthetic concern for many patients and increases the risk of an unacceptable esthetic dental result.
Before delivering treatment, it is paramount for the clinician to identify the cause, as they may be multiple, which will dictate the treatment plan.
Potential causes may include lip length, lip activity, clinical crown length, altered passive eruption, and vertical maxillary excess.
Surgical options to treat excess gingival display can include: gingivectomies, crown lengthening, lip repositioning, Botox injection, orthodontics, and orthognathic surgery.
Introduction: nature of the problem
Excessive gingival display, also known as a “gummy smile” is a common esthetic concern among dental patients. The excessive gingival display while smiling has been largely viewed as unaesthetic, leading to many patients seeking some form of treatment to address this issue. The etiology that plays into the gummy smile are often multifactorial, which is why an accurate diagnosis is paramount before any surgical treatment. In this article, we discuss the etiology, classification, diagnostic guidelines, and the current treatment options that can be rendered based on the etiology of the gummy smile.
The gummy smile has been largely defined as a nonpathological condition causing esthetic disharmony, in which more than 3 to 4 mm of gingival tissue is exposed when smiling. Fig. 1 shows a classic presentation of excessive gingival display while smiling. The anatomic landmarks that factor into the gummy smile are the maxilla, lips, gingival architecture, and teeth. All of these anatomic structures must lie in harmony with one another to achieve an esthetic smile. When diagnosing and treating patients with a gummy smile, the clinician must accurately understand and identify the etiology. In addition, multiple etiologies can simultaneously be responsible for the excess gingival display ( Box 1 ) and each cause must be accurately identified. Knowing the etiology, whether single or multiple, will dictate which treatment modality will be most appropriate for the patient.
Short lip length
Hypermobile/hyperactive lip activity
Short clinical crown
Altered passive eruption
Vertical maxillary excess
Diagnosis of excessive gingival display
When a patient presents with a chief complaint of their gummy smile, several steps must be taken to arrive at an accurate diagnosis. Furthermore, to correctly identify the etiologic, anatomic, and pathologic causes of a gummy smile, a well-defined diagnostic process should be used as shown in Box 2 .
Patient medical history
Lip analysis: static versus dynamic
Rest position analysis
Dental analysis: crown length and incisal margin
Obtaining a thorough medical history is always of great importance when arriving at a diagnosis. Key elements include the patient’s age and overall health. The patient’s age can indicate the eruptive stage of the dentition, and the overall health can indicate to the clinician any contributing factors to the patient’s condition.
A thorough evaluation of the facial profile of the patient can provide useful information to help identify the cause of the gummy smile. The facial thirds can be evaluated in the frontal and lateral views to determine any deficiencies or excess in the midface. An increase in the ratio of the middle third of the face may indicate vertical maxillary excess (VME). Many authors will agree that VME is the most common extraoral cause of the gummy smile. Cephalometric analysis can be used to help identify VME. Patients with VME usually end up having a skeletal class II relationship. Most patients with moderate to severe VME will require some form of orthognathic surgery as the form of treatment.
An analysis of the upper lip to assess for excessive gingival display should be done in both static and dynamic positions. Upper lip length and lip mobility should be assessed to identify the contributing factor to the gummy smile. The upper lip length is measured from subnasale to upper lip stomion with an average of 20 to 22 mm. Measurements less than this can be classified as a short lip and patients may present with lip incompetence and a gummy smile. In the dynamic analysis, hypermobility of the levator labii superioris muscles results in a higher position of the lip and increase exposure of the teeth and gingiva while smiling. Therefore, when it comes to the lips, the cause of the gummy smile can either be from the lip length, the hypermobility of the lip or both.
During the dental analysis, the clinician should analyze the 3D position of the incisors in the rest position. The interlabial gap can be assessed and measure with normal gap distance ranging from 0 to 4 mm. When there is a large interlabial distance exposing an excessive amount of incisal margins, VME, overeruption, or short lip should be suspected. The horizontal and vertical dimensions of the clinical crown should be measure and analyzed. A short clinical crown could be due to wear of the incisal edge or altered eruption. By analyzing the incisal edge and the patient’s age the clinician can determine if length discrepancy is located at the incisal margin or at the gingival margin.
The initial evaluation during the periodontal examination aims to diagnose the pathologic and nonpathological changes in the architecture of the periodontium. Probing depths, clinical attachment levels, and gingival recession should all be assessed and measured. If the patient presents with a clinical short tooth, the etiology must be identified as to whether it is due to inflammation, gingival hyperplasia, or altered eruption.
Altered Passive Eruption
Altered passive eruption is defined as a condition in which the relationship between teeth, alveolar bone, and the soft tissues create an excessive gingival display. Normal tooth eruption occurs in an active and passive phase. The active phase involves the movement of the tooth out of the alveolar bone into occlusal position. The passive phase is the exposure of the crown as a result of apical migration of the gingival tissues. The apical migration occurs in 4 stages as listed in Box 3 . Altered passive eruption is the failure of the gingival/dental complex to migrate apically past stage 2, with the most obvious sign being a short looking tooth. When making the diagnosis of altered passive eruption, the lips need to be assessed in repose and while smiling. Ruling out a hypermobile lip is necessary before making the diagnosis of altered eruption. A normal translational movement of the lip from rest is about 6 to 8 mm and up to 10 mm in a hypermobile lip situation. If the patient is deemed to have a hypermobile lip then the clinician should consider lip repositioning surgery or botulinum toxin A injections. Dental-alveolar extrusion is commonly treated with orthodontic intrusion. Treatment options are discussed later in this article. A key element to arriving at a diagnosis is noting the location of the cementoenamel junction (CEJ) in the gingival sulcus. The CEJ normally resides just apical to the free gingival margin of the crown. Conversely, the CEJ can reside up to 10 mm apical to the free gingival margin in altered passive eruption. If the CEJ can be detected in the gingival sulcus, and all other etiologies have been ruled out, a diagnosis of altered passive eruption can be made.
Stage 1: Teeth in plane of occlusion, JE on the enamel
Stage II: Epithelial attachment rests partly on enamel and cementum apical to CEJ
Stage III: JE lies completely on cementum with base of sulcus at CEJ
Stage IV: All of stage III with a portion of the root clinically exposed
Surgical treatment options
It cannot be overstated that, before any surgical treatment, the etiology must be identified to guide the appropriate treatment. After an etiology has been determined, the clinician should develop the appropriate treatment options to present to the patient, including all risks, benefits, and alternatives. The clinician must listen to the patient’s overall goal and must curtail the treatment to the patient’s specific needs. Not every patient will want to undergo orthognathic surgery to address their VME, so the clinician must present alterative treatment options to achieve the patient’s overall goal with realistic expectations. Different surgical methods are discussed in this section based on the etiology of the excessive gingival display.
The hallmark of an “ideal smile” entails the exposure of the entire length of the maxillary teeth with approximately 1 to 3 mm of gingival exposure. Lip repositioning surgery can be used to address excessive gingival display when the etiology is mild VME or a hypermobile lip. Lip repositioning narrows the vestibule limiting muscle pull, which restricts gingival display while smiling. The procedure can also be used in conjunction with crown lengthening or a gingivectomy.
Lip repositioning has been documented as being performed by various methods. The intended goal is to remove a strip of mucosa and shortening the vestibule, thereby restricting the muscle pull of the elevator muscles during smiling. This can be done traditionally using a scalpel, electrocautery, or even a laser surgical approach.
Rubinstein and Kostianovsky first presented the procedure of surgical lip repositioning in 1973 in the plastic surgery literature. The procedure has been subject to many modifications, including preservation of the maxillary labial frenum. Box 4 outlines the traditional surgical approach taken to perform lip-repositioning surgery. The amount of mucosa to remove is based on the “twice the amount of gingival display rule.” It is common practice to prescribe oral antibiotics (amoxicillin 500 mg 3 times a day), nonsteroidal anti-inflammatory drugs (ibuprofen 600 mg 4 times a day), and 0.12% chlorohexidine rinse twice a day as postoperative prescriptions. Postoperative instructions as outlined in Box 5 should be given written and verbally to the patient before discharge. In Figs. 2–4 , you can see the distinct changes in the amount of gingival display from preoperative to postoperative after having the lip-repositioning surgery performed. Contraindications to lip repositioning include minimal zones of attachment and severe VME. Postoperative complications that should be discussed with the patient include, pain, bruising, swelling, mucocele formation, and possible relapse.
0.12% Chlorhexidine rinse for 1 minute preoperatively
Administer local anesthesia in vestibular mucosa and lip between left and right upper first molar (2% lidocaine w/1:100k epinephrine)
Mark incision outline with sterile surgical marking pen
Partial thickness horizontal incision made 1 mm coronally to mucogingival junction from first molar to first molar
Second horizontal incision was made in the labial mucosa 10 to 12 mm apical to first incision
Connect the 2 incisions at the mesial line angles of the right and left maxillary first molar in elliptical outline
Remove strip of outlined mucosa by a superficial split thickness dissection
Control bleeding with electrocoagulation as needed
Take care to avoid damaging minor salivary glands in submucosa
Use 4 to 0 silk sutures to close incision lines in interrupted fashion