Gummy Smile: Mercado-Rosso Classification System and Dynamic Restructuring with Hyaluronic Acid

Abstract

Background: Gummy smile (GS) is a nonpathological condition causing esthetic disharmony in which an excessive amount of gingival tissue is exposed when smiling. Nowadays, there is not unanimous agreement regarding both classification and management of GS. This study aimed to present an organized and comprehensive clinical classification of the GS, as well as to discuss a therapeutic approach, with hyaluronic acid dermal fillers.

Methods: This study is presenting the clinical experience of the authors regarding GS.

Results: The Mercado-Rosso GS classification has into account aesthetic aspects, etiopathogenetic criteria, and functional aspects of the smile. According to Mercado-Rosso GS-classification-system, GS is divided into 3-types: Type 1, characterized by a lack of support and/or a lack of projection of the upper maxilla; Type 2, due to an imbalance between the strength (excess) and the resistance (defect) of the levator muscles; and Type 3, defined by an excessive strength of the zygomatic muscles, which causes a wide smile and an excessive visualization of the molar teeth.

Conclusions: The Mercado-Rosso GS classification system is a tool that facilitates the diagnostic and therapeutic approach to the gummy smile. RD Dynamic Restructuring® constitutes a comprehensive therapeutic approach that makes reference to both the effect of the HA filler on the muscle movement and the balance between the muscle strength and the resistance of the soft tissue to be folded in different facial structures).

Level of evidence: Level V.

Keywords: Classification; Dynamic restructuring; Facial muscles; Gummy smile; Hyaluronic acid.

Fig. 1

Stages in the genesis of a full smile [1]. a Stage 0: rest position. b Stage 1: upper lip elevation to the nasolabial fold. c Stage 2: maximum upper lip and fold elevation. Adapted from Peck et al.

Fig. 2

Different muscles involved during a maximum smile. The superior lip and the fold raise due to the action of three different muscle groups: The levator labii superioris (LLS), zygomaticus major (ZM), and superior fibers of the buccinator (BC)

Fig. 3

Mercado-Rosso gummy smile classification

Fig. 4

Treatment strategy of gummy smile Type 1. There is an important lack of structural support that, besides a gummy smile, causes a drop of the tip of the nose Upper image: The recommended strategy is 0.6 mL/per side of high-density hyaluronic acid (HA) filler (RHA4^®, Teoxane, Geneve, Switzerland) administered by means fanning retrograde technique with a blunt microcannula. In this case it would be necessary to inject an additional bolus (blue ellipse) of 1 mL–2 mL of HA 23 mg/mL. Lower image: The recommended strategy is 0.6 ml/per side of high-density hyaluronic acid (HA) filler (RHA4^®, Teoxane, Geneve, Switzerland) administered by means fanning retrograde technique with a blunt microcannula. Additionally, small boluses (blue ellipses) 0.4 mL–0.6 mL de HA 23 mg/mL at the end of each fanning retrograde administration upon reaching the central region of the white lip and circumscribed to the edges of the insertion of the nasal wings. a Frontal view. b lateral view

Fig. 5

Patient with a gummy smile type 1 before (a–c) and after treatment (d–f). In this case, a retrograde fanning technique from the piriformis fossa to the midline, by means a blunt microcannula (25G and 50 mm), was used to inject 0.6 ml/side of HA (23 mg/ml) (RHA4®, Teoxane, Geneve, Switzerland) in a supramuscular plane. After treatment (D, E, and F images), it is possible to see how the RD Dynamic Restructuring^® technique has created a structural support and the white lip was enhanced

Fig. 6

Treatment strategy of gummy smile Type 2. The recommended strategy is a total of 0.6 mL–0.8 mL/per side of a high-density hyaluronic acid (HA) filler (RHA4®, Teoxane, Geneve, Switzerland) administered at the piriformis fossa (0.2 mL–0.4 mL/side); at the levator labii superioris alaeque nasi (0.2 mL/side); and at the anterior nasal spine (0.2 mL/side). a Frontal view. b Lateral view

Fig. 7

Patient with a gummy smile Type 2. The patient was treated with a bolus of 0.6 ml (per side) of a 23 mg/mL hyaluronic acid filler (RHA4®, Teoxane, Geneve, Switzerland) administered by using a fanning retrograde technique with a 25G blunt microcannula in the white lip (black lines); a bolus of 0.3 mL/per side of HA 23 mg/ml administered at the piriformis fossa (red ellipse) with a 25G blunt microcannula; 0.1 ml/per side of HA 23 mg/mL at the levator labii superioris alaeque nasi (dark blue ellipse); and 0.1mL/per side of HA 23 mg/mL at the anterior nasal spine (between nasal spine and orbicular) (light blue ellipse). Vermillion was not treated. a Frontal view before treatment; b Lateral view before treatment; c Frontal view after treatment; d Lateral view after treatment

Fig. 8

Treatment strategy of gummy smile Type 3. This patient combines a Type 1 gummy smile with an overactivity of the zygomaticus muscles. Besides the treatment of the Type 1 gummy smile (see Fig. 4), this patient needed a total amount of 0.4–0.8 mL of 25 mg/mL HA per side (Ultradeep®, Teoxane, Geneve, Switzerland) distributed in 2 boluses (0.2 mL–0.4 mL/per bolus/per side) (blue ellipse). This patient required an additional bolus of (blue ellipse) of 1 mL–2 mL of HA 23 mg/mL (RHA4®, Teoxane, Geneve, Switzerland) (green star)

Fig. 9

Patient with gummy smile Type 3. The patient was treated with two parallel bolus of 0.3mL (per side) of a 25 mg/mL hyaluronic acid (HA) filler (Ultradeep®, Teoxane, Geneve, Switzerland) with needle in the zygomatic ligament at the malar region (blue ellipses), bolus of 0.3 mL of HA 23 mg/mL (RHA4®, Teoxane, Geneve, Switzerland) at the piriformis fossa (red ellipse) with a 25G blunt microcannula; 0.1 mL/per side of HA 23 mg/mL at the levator labii superioris alaeque nasi (green ellipse); and 0.1mL/per side of HA 23 mg/mL at the anterior nasal spine (between nasal spine and orbicular) (light blue ellipse); and 0.4 mL of HA 23 mg/mL by using a fanning retrograde technique with a 25G blunt microcannula in the white lip (black arrows). Vermillion was not treated. a Frontal view before treatment. b Frontal view after treatment