Treating Excessive Gingival Display Without Orthognathic Surgery

One such esthetic condition that can be treated with a range of approaches is excessive gingival display when speaking and smiling, which is more commonly known as a "gummy smile." The prevalence of excessive gingival display is approximately 7% among males and 14% among females,^1,2 and it tends to affect the confidence of these individuals in social situations. In general, the etiology of excessive gingival display determines the treatment approach that should be followed. Etiologic factors include vertical maxillary excess (VME), altered passive eruption, anterior dentoalveolar extrusion, short or hyperactive upper lip, and gingival hyperplasia.³

Depending on the specific presentation, possible treatment approaches for excessive gingival display include crown lengthening procedures, orthodontic leveling of the gingival margins, maxillary tooth intrusion, and orthognathic surgery.⁴

VME, which creates the appearance of a long face, gummy smile, and occasionally an open bite, is defined as excessive growth of the maxilla and associated dentoalveolar structures in an inferior direction. It can affect the whole maxilla or just parts of it. Traditionally, VME is treated with fixed orthodontics followed by orthognathic surgery and includes a Le Fort I osteotomy.⁵ This treatment provides an ideal long-term outcome but is associated with many risks and a high rate of morbidity.

In cases involving altered passive eruption, a clinical situation in which the gingival tissues move coronally past the cementoenamel junction, as opposed to altered active eruption, which is also accompanied by the proximity or coincidence of the alveolar crest to the cementoenamel junction, the result is usually smaller appearing clinical crowns. This can exaggerate the appearance of excessive gingival display. Addressing altered passive eruption is simpler than addressing VME. Surgical crown lengthening can provide an immediately improved appearance, either by uncovering the existing clinical crown by means of gingivectomy alone or in combination with an apically displaced flap and osseous resection.⁶ When compared with surgical methods to address VME, the healing from crown lengthening procedures is usually less eventful and occurs in a shorter period of time. However, the decision to provide this treatment should take into consideration the fact that the natural process of passive eruption, which results in increased clinical crown length, continues throughout the teenage years.⁷ Other complications include the creation of "black triangles," root hypersensitivity, root resorption, and transient mobility of the teeth.⁸

Oftentimes, combining crown lengthening procedures with the placement of porcelain laminate veneers can help to overcome these issues and further reduce the soft-tissue display when speaking and smiling. Although the use of veneers has been reported to be a very successful treatment modality (95.5%), longevity is usually the variable of concern. Research indicates that the occurrence of fracture, debonding, or secondary caries or the need for endodontic treatment are all associated with the failure of porcelain laminate veneers⁹; however, by modifying the preparation designs of these restorations (eg, keeping preparation margins in enamel and supragingival where possible, having proximal chamfer preparations in enamel, and having overlapped incisal edge preparation types with mini chamfers or butted margins) their longevity can be increased.^9,10

One of the complications associated with crown lengthening and placement of porcelain laminate veneers is the inadvertent invasion of the "biologic width," which was first described by Ingber and colleagues in 1977, who credited D. Walter Cohen with first coining the term.¹¹ Biologic width refers to the distance established by the junctional epithelium and the connective tissue attachment to the root surface of the tooth above the alveolar bone crest, which has an average dimension of 2.04 mm (0.97 mm for the epithelial attachment and 1.07 mm for the connective tissue attachment). This can also be described as the distance between the deepest part of the gingival sulcus and the crest of the alveolar bone.

There are many treatment options available for patients who suffer from excessive gingival display that are less invasive than orthognathic surgery, including lip repositioning surgeries, plastic periodontal surgeries, restorative procedures, botulinum toxin injections, or combinations thereof.¹ According to a systematic review published in 2021, lip repositioning surgery can improve smile esthetics in the short term (up to 6 months) but demonstrates progressively decreasing efficacy, and a relapse of approximately 25% is to be expected after 12 months. However, when combined with myotomy or other treatment modalities, it resulted in outcomes that were more predictable and stable long term.¹²

As long as excessive gingival display is less than 8 mm, it can be successfully masked by lip repositioning surgery alone. Data collected by Simon and colleagues demonstrated that in cases with excessive gingival displays greater than 8 mm, the chances of unfavorable results increased significantly.^13,15 Lip repositioning surgery is performed to limit retraction of the upper lip elevator muscles. It involves removing a strip of mucosa from the maxillary buccal vestibule, but it can include additional procedures to increase predictability, such as detachment of labial muscles, application of a silicone spacer, myotomy of the levator labii superioris muscle in combination with a frenectomy, or even lip elongation in combination with rhinoplasty.^14,15 In 2018, after a randomized clinical trial, Tawfik and colleagues reported that lip repositioning surgery with myotomy resulted in greater esthetic improvement and higher patient satisfaction when compared with lip repositioning surgery alone.¹⁵

A shy but healthy 15-year-old girl came to the practice with her parents to see what options were available to treat her "small teeth and gummy smile." The clinical examination revealed that her excessive gingival display was a result of altered passive eruption and VME. In addition, her maxillary labial frenum had a coronal attachment close to her midline papilla. Extraoral photographs were acquired along with primary study model impressions (Figure 1).

First, ideal treatment was discussed with the patient. This involved a referral to a specialist orthodontist and oral maxillofacial surgeon and could have included orthodontics and orthognathic surgery. An alternative option was presented thereafter. This included realignment and intrusion of her upper anterior teeth, which would be followed by surgical crown lengthening and then lip repositioning surgery. When compared with ideal treatment, this approach would not have a similar long-term prognosis or stability but would be less invasive and completed over a shorter period of time. Porcelain laminate veneers could be used to complement this approach, but not until the patient was at least 17 years old due to the known changes that occur in the gingival levels during the teenage years.⁷

After considering the first avenue, the patient and her parents decided to pursue the alternative treatment approach and have it staged. The unpredictability of the extent of her outcome was stressed, but the patient was assured that a noticeable enough difference could be achieved to justify the approach.

Orthodontics

Treatment was initiated with fixed orthodontics on the patient's upper and lower teeth. For the first phase, the focus was on realigning her upper anterior ten teeth and intruding her upper anterior six teeth. A study conducted by Murakami and colleagues showed that intruding upper anterior teeth moves the gingiva in the same direction as the teeth but only about 60% as far, shortens the crown and deepens the sulcus by approximately 40% as much as the tooth intrusion, and results in no inflammation or swelling microscopically.^16,17

Molar tubes (First Molar Tubes [0.022 in ˣ 0.028 in], TP Orthodontics, Inc.) were placed on the patient's upper and lower first molars, and ceramic brackets with a slot size of 0.022 in (InVu^® Ceramic Readi-Base^® Brackets [0.022 in], TP Orthodontics, Inc.) were used on teeth Nos. 4 through 13 and teeth Nos. 20 through 29 (Figure 2).

Over the duration of the treatment, different archwire types and sizes were utilized, ranging from a 0.014 in nickel titanium wire (Reflex^® Nickel Titanium Wire, TP Orthodontics, Inc.) to a 0.016 in ˣ 0.022 in stainless steel wire (Shiny Bright Stainless Steel Aesthetic Wire, TP Orthodontics, Inc.), depending on the type of movement required to move the teeth into the planned final positions. This orthodontic phase took 12 months (Figure 3).

Crown Lengthening

Once the upper teeth were in the planned positions, the second phase of treatment was initiated, which involved crown lengthening for teeth Nos. 4 through 13 and a simultaneous frenectomy of the upper anterior labial frenum. An electrosurgery system (PerFect^® TCS II, Coltene) was used for both the gingivectomy and frenectomy (Figure 4). Because there was no plan to place any porcelain laminate veneers at this stage, osseous resection was avoided to ensure that the patient would not have any exposed root surfaces or potential black triangles for a prolonged period of time. If she decided to pursue porcelain laminate veneers at a later date, crown lengthening with osseous resection could be a possibility.

The soft tissue was allowed to stabilize for a healing period of 3 months, and then the orthodontic archwires, brackets, and molar tubes were removed. To facilitate retention of the dentition after orthodontic movement, fixed lingual and palatal wire retainers were placed from cuspid to cuspid and removable upper and lower Essix retainers were fabricated to retain from molar to molar.¹⁸

Lip Repositioning

After retention was ensured, the patient was able to move to the surgical phase for lip repositioning. Two parallel split-thickness incisions were made. The first one was located about 1 mm apical to the mucogingival junction, extending from the distal aspect of tooth No. 4 to the distal aspect of tooth No. 13, and the second one was located 8 mm to 10 mm apical and parallel to the first incision. This strip of mucosa was removed, and the levator labii superioris muscle was transected but not the levator labii superioris alaeque nasi or the levator anguli oris muscle (Figure 5 and Figure 6). After a synthetic absorbable suture (VICRYL RAPIDE^™, Ethicon) was used to reposition the lip, the patient was dismissed and recalled 2 weeks, 4 weeks, 3 months, and 6 months postoperatively to monitor the healing of the soft tissues and the short-term stability of the treatment outcome.

A beautiful result was achieved, and the patient expressed that she was ecstatic about it (Figure 7 and Figure 8). Although the treatment just masked the patient's underlying skeletal issue, the result was able to be achieved after only 18 months, and the patient didn't report experiencing any loss of sensation of her upper lip or the associated soft tissues. An even more esthetic result may have been achieved with the addition of direct or indirect laminate veneers, but the patient is expected to undergo some further skeletal and soft tissue changes during the next few years.

By discussing all viable avenues of treatment with our patients, we can assist them in making more informed decisions. Sometimes, they decide to explore treatment by dental specialists, but other times, they decide on alternative approaches that general dentists can offer. In the case report presented in this article, the patient's main complaint was able to be addressed with minimal intervention and uneventful healing.

Hanno Venter, BDS
Diplomate
International Congress of Oral Implantologists
Private Practice
Melbourne, Australia