Excessive gingival display: addressing multiple etiologies for optimal esthetic outcomes

Introduction

Excessive gingival display (EGD) and “gummy smile” are descriptive terms, not diagnoses per se, but currently epitomize how clinicians and patients communicate on this topic. As patients are increasingly conscious of the role their smile plays in social and professional situations, they often self-refer for EGD correction.

Etiologies

Identifying any health problem’s source or etiology embodies the ideal goal of its therapy. For EGD, individual or combined etiologies can be dentoalveolar or nondentoalveolar in origin.

Dentoalveolar etiologies involve the teeth and periodontium, and include short clinical crowns, altered passive eruption (APE), gingival overgrowth, and/or dentoalveolar extrusion. Nondentoalveolar etiologies include skeletal and/or facial soft tissue anomalies, including hypermobility of the upper lip, short upper lip, and/or vertical maxillary excess (VME). We frequently identify APE and mild VME in GS cases in our periodontal practice.

Confirmation of VME by cephalometric analysis usually identifies a steep mandibular plane and an increased SNGoGn angle (inclination of mandible relative to cranial base). This underscores the orthodontist’s role in identifying EGD, as it can become more apparent and recognizable after orthodontic treatment.

Because combined etiologies more commonly underlie EGD, multitreatment interdisciplinary approaches are frequently indicated. Biologic width (BW) is a fundamental concept that retains the clinician’s focus in periodontal-restorative discussions. BW is a zone of connective tissue and junctional epithelium between the alveolar crest and free gingival margin that must be preserved during restorative procedures to maintain periodontal homeostasis and avoid creating inflammatory processes in the dentogingival unit.

Preservation of both BW and the width of attached gingiva (even in unrestored anterior teeth) cannot be overemphasized in determining whether appropriate etiology-based EGD treatment(s) will include gingivectomy, osseous resection, or a combination of both.

Treatment of EGD

Most dentoalveolar causes of EGD can be effectively treated using restorative care, periodontal plastic surgical approaches, orthodontics, and/or surgically facilitated orthodontic therapy. Nondentoalveolar sources rely on orthognathic surgery (i.e., maxillary impactions), facial plastic surgical approaches, notably relying on myotomy or resection of the smile muscles through a nasal columellar incision. Botulinum toxin A effectively corrects GS for hypermobile lip and mild VME patients, but requires repeated treatment. A lip-repositioning procedure has been popularized recently to correct such GS cases permanently.

When APE is present alone or with other dentoalveolar factors, crown lengthening (CL) that includes gingival resection and/or osseous surgery can significantly reduce gingival display at rest and in full smile. Short or worn teeth may require restorations. Orthodontics may also be indicated to recover an extruded dentoalveolar complex.

For VME, orthognathic surgery may be indicated. To mask mild to moderate cases of VME, and/or hypermobile upper lip, treatments such as reverse vestibuloplasty (i.e., lip repositioning) via a coronally advanced mucosal flap effectively narrow the vestibule, restricting mobility of the elevator smile muscles and upper lip.