Gummy Smile Causes (Etiology)
Excessive Gingival Display=gummy smile=EGD
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). APE and mild VME is the most common case seen.
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.
Orthodontics: Intrudes over erupted teeth and levels them to correct position so that it eliminates gingival display.
Periodontal surgery: Crown lengthening to move gingival levels apically, typically performed on short teeth.
Orthognathic surgery: Moves the maxilla in an apical direction impacting the maxilla.
Botox: Studies suggest Botox, when injected into the muscles of the upper lip can to be an effective method; however, the improvement is temporary and must be repeated every three to six months.
Lip repositioning surgery: Severs the muscles that elevate the lip so it can no longer rise as far in a smile. An irreversible solution diagnosis is the key to a successful outcome.
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.
When APE coexists with HUL and/or VME, combining this procedure with CL produces optimal results.
Surgical options for gingival display Nov 12
- Lefort I
- Ortho intrusion if just anterior supra-erupted
- Plastic surgery ie lip repositioning for hyper-mobile lip or botox
Many say the lip returns in 12 months to some extent. I am unsure on that as here is a Ishida 2010 study showing holding up well at 6 months. Also look to do a 2:1 for removal remove twice as much as want to reduce showing, again unsure on that claim.
Really cool all on 4 case with a gummy smile. This allows for less bone reduction while maintaining a result that does not show the transition.