Treatment of a “Gummy Smile”: Understanding Etiology is Key to Success

Jeff Bynum, DDS

Excessive gingival display, commonly referred to as a “gummy smile,” is an esthetic concern for many patients. For the dentist, excessive gingival display increases the risk of an unacceptable esthetic result. This risk is compounded when restoration of anterior teeth is indicated. Multiple etiologies may be responsible for excessive gingival display. Therefore, prior to beginning treatment it is crucial for the dentist to clearly understand and identify which etiologies will influence the available treatment options. Potential etiologies include: lip length, lip activity, clinical crown length, dentoalveolar extrusion, and vertical maxillary excess (VME).¹

Management of this high-risk situation requires interdisciplinary treatment planning to be used based on the identified etiologic factors that have contributed to the excessive gingival display. A customized, specific therapy or group of therapies can then be developed for each patient. This is equally critical whether the treating dentist will be performing the treatment alone or with the aid of the interdisciplinary relationships of the periodontist and orthodontist.²

Factors Influencing Treatment Options

When making treatment planning decisions, a primary goal is to decrease a patient’s risk among all of the diagnostic categories without increasing the risk in any other category. After the prudent practitioner has determined the etiology of a given condition, developed appropriate treatment options, determined the risks of treatment or no treatment, and presented these options to the patient, it is imperative that the patient understand the limitations of the recommended treatment, as well as why the options presented are necessary to achieve a successful result. Many dental procedures are now marketed directly to the patient, who may, therefore, request an alternate form of treatment that he or she has seen advertised.

Patients may also decline some of the treatment options presented by their dentist. Many factors affect patient treatment acceptance, such as cost, expectations, willingness to undergo certain procedures, and willingness to accept compromise. The treating doctor needs to identify these factors for the patient, so they can be openly discussed when finalizing the treatment plan. A true informed decision can be made when patients understand the limitations of each treatment option, accept the associated risks, and realize the importance of avoiding choices that may compromise the ability to achieve an acceptable result. An unacceptable result would increase risk or decrease the prognosis for patient satisfaction.

Clinical Case Overview

A 48-year-old woman presented for comprehensive examination and treatment. Her medical history was non-contributory, consisting simply of a history of treatment for high cholesterol and presenting no contraindications for dental treatment. Her dental history revealed a record of routine dental care. She reported that she was aware of squeezing to make her teeth fit together and related a history of sore teeth.

Her primary concern was esthetics. She was unhappy with the appearance of her teeth and her smile. She had noticed that her teeth had become increasingly “worn and chipped.” She was concerned with the amount of wear and noticed that her teeth appeared “shortened and angled inward.” She desired to have them lengthened and restored to achieve a more attractive smile, which included reducing the amount of gum tissue that displayed in her smile (Figure 1).

Diagnostic Opinion

Periodontal: Clinical and radiographic examination revealed AAP type II classification. Periodontal findings included slight bleeding on probing, probing depths less than or equal to 3 mm, and bone heights within 2 mm of the cementoenamel junction (CEJ). Several areas of recession were noted, but it was determined that these areas were due to anatomic liability and not the result of periodontal disease.

Risk: Low
Prognosis: Good

Biomechanical: The patient had a long history of caries, large fillings, fractured teeth, root canal therapy, and crowns. Multiple structurally compromised teeth remained. Active carious lesions were present. Open crown margins were evident upon examination. Evidence of acid erosion was also noted and was discussed with the patient to determine if the etiology of the erosive lesions was either dietary and/or systemic. The patient had noticed symptoms of acid reflux concomitant with the use of appetite suppressants and dietary restrictions, which she had used frequently for weight control. Endodontic therapy for tooth No. 14 appeared to have only treated the palatal root. The patient’s endodontist had evaluated this tooth and determined that the remaining canals were calcified and non-negotiable. The tooth had remained asymptomatic and free of pathology for more than a decade since the existing endodontic therapy had been performed.

Risk: High
Prognosis: Poor

Functional: The patient explained that her teeth had become worn, thinner, and shortened in the past 5 years. This would indicate that the condition was active (Figure 2). She reported having to squeeze her jaw in order for her teeth to fit together. She also reported experiencing some sore teeth during the daytime. Mild attrition was noted on the anterior teeth, with evidence of erosion also present. The previously placed cosmetic bonding for diastema closure was chipped (Figure 3). The majority of the posterior teeth were covered with full-coverage, cohesively retained restorations, which masked evidence of attrition. Based on these clinical signs and the patient’s dental history, a diagnosis of occlusal dysfunction was made. No joint noises or deviations were evident. The patient had a maximum opening of 51 mm. Both the load and immobilization tests were negative.

Risk: Moderate
Prognosis: Fair

Dentofacial: A main desire of the patient was to alter the high lip dynamics and excessive gingival display with which she presented. With the patient at rest position or repose, 2 mm to 3 mm of maxillary incisal edge displayed, and the canines displayed roughly at the 0 degree position.³ In full smile, the entire tooth and an additional 4 mm to 5 mm of tissue displayed. Gingival asymmetries were evident and obvious due to the excess gingival display. The patient was also unhappy with her tooth size, shape, and position.

Risk: High
Prognosis: Poor
Etiologic Factors

Etiologic Factors

Understanding the etiology of the excessive gingival display was crucial in order to develop an appropriate treatment plan. The etiologic factors in this case involved the following:

• Hyperactive or hypermobile lip: Lip mobility of 12 mm; average lip mobility is 7 mm to 8 mm of movement (Figure 4 and Figure 5).⁴
• VME: The lower third of the face is longer than the upper and middle third.⁵
• Dentoalveolar extrusion: Gingival asymmetry.
•  High crest on maxillary central incisors: <3 mm measured from osseous crest to free gingival margin (FGM) (Figure 6).⁶

The treatment decisions were complicated because treatment recommendations differ for each of these etiologies. Before treatment was initiated, a discussion of the treatment options, risks, and prognosis was required.

Treatment Plan

The goal of all of the treatment options presented was to reduce or manage risk in all categories without increasing risk in any category. There were four main goals in the treatment of this case:

• Decrease the biomechanical risks by eliminating the active carious lesions, restoring the defective restorations, and protecting the structurally compromised teeth.
• Decrease the functional risks by eliminating the occlusal dysfunction and creating equal intensity, bilateral, simultaneous contacts in centric relation position.
• Decrease the excess gingival display.
• Increase the overall esthetics of the smile by improving the intra-arch tooth positions and restoring the teeth to a more attractive size, shape, and color.

Of the four main goals, decreasing the excess gingival display was the most complex both in etiology and treatment options. Each of the four determined etiologies of the condition required a different treatment modality. The hyperactive or hypermobile lip would require treatment options consisting of behavior modification, botulinum toxin or similar treatment, or surgical modification.⁴ The VME would demand orthodontics and potentially orthognathic surgery.⁵ The dentoalveolar extrusion would entail crown lengthening surgery, orthodontic intrusion, or segmental osteotomy. Finally, the high crest dentogingival complex would require supragingival margins or crown lengthening surgery.⁶

The patient desired to have a more esthetic smile created with the least invasive treatment modality. She was resistant to orthognathic surgery and traditional orthodontia. It was decided to treat the patient with clear aligner orthodontic trays to expand the maxillary arch and leave spaces to allow for proper intra-arch tooth relationships, intrude the maxillary anterior teeth, and improve the occlusal planes. The orthodontic treatment was planned to leave the maxillary teeth slightly linguoverted to decrease the amount of tooth reduction required at the restorative phase of treatment. Esthetic crown lengthening was planned to further decrease the excess gingival display, eliminate the gingival asymmetries, and create a normal crest dentogingival complex to decrease the risk of biologic width invasion.

Enamel-supported porcelain veneers were planned for the maxillary anterior teeth to restore them to the desired esthetic result without significant biomechanical compromise to the teeth.^7,8 To address the functional, esthetic, and biomechanic needs, the maxillary premolar teeth were planned to receive porcelain onlay-style restorations with a facial veneer component.⁹ Minimal preparation of the facial surface would maintain the facial enamel and decrease the amount of structural compromise. Core-supported, all-ceramic, cohesively retained restorations were planned for the maxillary molars to replace the defective metal-ceramic restorations present, decreasing the biomechanic compromises by removing the existing recurrent decay and increasing the esthetic result. Metal-ceramic, full-coverage restorations were planned to restore the mandibular molars, as they were not in the esthetic zone.

Treatment Phases

The initial phase of the treatment was caries control. Carious lesions were conservatively removed and restored with glass-ionomer restorations. This was done to stop the progression of the decay, as the treatment was expected to take more than a year to complete.

Orthodontic treatment was then initiated and completed as planned in 10 months. As a result, intra-arch tooth position was improved and the maxillary anterior teeth intruded utilizing clear aligner orthodontic trays (Figure 7). Six months after the completion of the orthodontic treatment, new records were taken and a Kois deprogrammer was fabricated and delivered to establish the appropriate joint position. A centric relation bite record was taken and a diagnostic wax-up was fabricated. This diagnostic wax-up was used to construct a surgical template for the crown lengthening surgery, an intraoral esthetic mock-up for patient approval, and a tooth preparation guide.

The next phase of treatment was esthetic crown lengthening. Crown lengthening was performed after orthodontic treatment because the amount of orthodontic intrusion, utilizing the clear aligner system alone, was not sufficient to reduce the amount of gingival display to achieve the desired result. After appropriate local anesthesia was performed, a sulcular incision was made and a full-thickness flap was raised from the maxillary second premolar to second premolar (Figure 8). Osseous resection was completed to the planned measurements using the surgical guide, thereby establishing idealized tooth proportions and biologic width.¹⁰ An apically repositioned flap was sutured, and the patient was allowed to heal for 16 weeks.

Once the gingival tissue was adequately healed, a silicone matrix fabricated from the diagnostic wax-up was filled with a self-curing bisacryl material and seated intraorally directly over the unprepared maxillary teeth. This provided an esthetic mock-up for evaluation of tooth size, shape, and length. The unanesthetized patient was then afforded an opportunity to evaluate and approve the planned outcome of the smile design (Figure 9 and Figure 10).¹¹ Once the patient and treating clinician both approved the mock-up, the patient was adequately anesthetized. The mock-up was left on the teeth, and tooth preparations initiated directly on the mock-up. This allowed for the appropriate amount of preparation to facilitate the final restorative outcome without removing any unnecessary tooth structure.

The maxillary anterior and planned posterior teeth were prepared in the same visit, and the provisionals were fabricated in segments. The posterior provisionals were trimmed, polished, and cemented and then equilibrated to centric relation position. Final impressions were made of the prepared anterior teeth and sent to the prosthetic laboratory for fabrication (Figure 11). The patient was seen 2 days later for impressions of the provisional restorations and photographs. These records were relayed to the laboratory to guide final restoration fabrication to match the patient-approved mock-up contours and tooth position.

Once the final anterior restorations were fabricated by the lab, they were approved and cemented with appropriate adhesive protocols, and the occlusion was refined. The posterior teeth were then prepared, impressed, and sent to the lab to complete the rehabilitation. Once the posterior restorations were fabricated, they were adjusted and cemented using appropriate adhesive and cohesive protocols. By segmenting the restorations anterior to posterior, both the clinician and the lab were able to maintain control over the joint position and vertical dimension of occlusion. This was maintained by the equilibrated posterior provisional restorations. Completing the anterior segment first helped ensure that proper canine occlusal stops and anterior guidance would be appropriate; it also ensured that the posterior contacts would be fabricated to equal intensity, bilateral, and simultaneous contact without compromising the guidance already established in the anterior segment.

Case Summary

The treatment performed was designed to meet the desired outcome of the patient and to address the areas of risk established in the preoperative assessment. The dentofacial risk was reduced by decreasing the amount of gingival display (Figure 12). Although the high lip dynamics remained, the amount of tissue displayed in full smile was significantly decreased without performing orthognathic or plastic surgery (Figure 13 and Figure 14). Decreasing the amount of gingival display and avoiding orthognathic surgery were both important to this patient.

The functional risk was decreased by creating a simultaneous, bilateral, equal intensity “home” in a stable joint position, decreasing the premature loading during function. The biomechanical risk was reduced by removing the active carious lesions and restoring structurally compromised teeth that were at risk for fracture (Figure 15 and Figure 16). It could be argued that the biomechanical risk was increased slightly on the anterior teeth by removing tooth structure from the facial and incisal aspects. Careful attention to maintaining the facial enamel and the cingulum with orthodontia and preparation design helped to mitigate this risk.^7,8 The periodontal risk remained low even though some alveolar bone was removed from the facial aspect of the anterior teeth.

The patient was very satisfied with the outcome. She was further pleased that the outcome was achieved while avoiding certain treatment options to which she was opposed.

Conclusion

Patients presenting with high dentofacial risk and high esthetic demand can be challenging for the clinician. Multiple treatment options exist for the treatment of conditions with multiple etiologies. Understanding the etiologies of the individual conditions and developing multidisciplinary treatment options is paramount to a successful outcome.² Clearly defining the risks and potential consequences for the patient for each treatment modality is also of significant importance to ensuring a positive result and gaining patient acceptance of appropriate treatment modalities. A balance should be reached between minimizing the risk in one category and potentially increasing the risk in another. Developing treatment options that do not increase the risk should be considered even if the patient’s expectations must be tempered.

Acknowledgment

The excellent laboratory support and ceramics were provided by Wayne Payne, Payne Dental Lab, San Clemente, California.

About the Author

Jeff Bynum, DDS Clinical Instructor, Kois Center, Seattle, Washington; Private Practice, Valrico, Florida

References

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