Clinical contribution
Botox and the gummy smile

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Abstract

This article reports three cases of Botulinium neurotoxin used to temporarily resolve gingival excess in three female patients who had refused surgical treatment for this condition.

Riassunto

L’articolo riporta tre casi di neurotossina di Botulino utilizzata per risolvere temporaneamente l’eccesso di gengiva in tre pazienti donna che hanno rifiutato l’intervento chirurgico.

Résumé

Cet article montre trois cas de neurotoxine de Botulinium utilisée pour resoudre temporairement l’excès gingival dans trois patients féminins qui avaient refusé le traitement chirurgical pour cette condition.

Resumen

Este artículo reporta tres casos de sexo femenino, tratadas con neurotoxina botulínica aplicada temporalmente para resolver la hiperplasia gingival. En los tres pacientes había sido excluido el tratamiento quirúrgico.

Introduction

The exposure of 2 mm or less of gingival tissue is generally considered to be one of the main factors determining an aesthetically pleasing smile.1 A gummy smile, on the other hand, is characterised by excessive exposure, i.e. more than 2 mm, of the maxillary gingiva.

Although the incidence of this excessive exposure has not yet been documented, it appears to be high and, in many cases, is seen by the patient as aesthetically debilitating and may lead to extreme embarrassment and lack of self-esteem.2

Approximately twice as many women seem to be concerned about this problem than men.3

Variability in gingival exposure may be correlated with muscular, gingival or skeletal factors, or a combination thereof. A gummy smile may be caused by a short upper lip, short crowns on the upper front teeth, vertical maxillary excess, gingival hypertrophy or hyperactivity of the elevator muscles of the upper lip.4, 5, 6, 7

Choice of treatment of this problem will thus depend on the causative factor or factors, and surgical intervention may be an option.

In order to choose the most suitable therapeutic approach, Monaco et al.8 proposed that the gummy smile be classified according to aetiopathogenic factors. For example, according to these authors, a high smile line, as defined by Peck,3 can be categorised as one of the following types: dentogingival, due to an altered dental eruption with consequent reduction in clinical crown exposure; muscular, caused by hyperactivity of the perioral muscles; dentoalveolar, resulting from excessive sagittal and vertical growth of the upper jaw; and, finally, mixed, arising from a number of concomitant causal factors.

Furthermore, the authors suggested that a series of clinical and photometric factors be evaluated from both frontal and lateral perspectives when the patient smiles, define the nature and entity of the problem.

The factors to be evaluated in these cases include structural parameters such as the distance between the subnasal point and the cutting edge of the incisors; occlusal parameters like overbite, overjet and the inclination of the occlusal plane; or dento-gingivo-labial parameters, namely the length of the coronal crown, the length of the upper lip, and the interlabial gap, at rest and during maximal smile.

In gingival overexposure due to hyperfunctionality of the upper lip elevator muscles (including the levator labii superioris, levator labii superioris alaeque nasi, levator anguli oris, zygomaticus major, zygomaticus minor, and the depressor septi nasi muscles) surgical procedures have been used to resolve the problem.9, 10, 11

More recently, however, the use of Botulinum neurotoxins (BT), to counteract muscular hyperactivity and to reduce the extent of gummy smile, has been proposed.

These neurotoxins (BT) are zinc-dependent proteases produced by Clostridum Botulinum, an anaerobic gram-positive bacterium. Thus far, seven different BT serotypes (from BT-A to BT-G) have been identified; these neurotoxins cause the flaccid muscular paralysis which characterises Botulism in man and several animal species and which may be fatal if the respiratory muscles are affected.12

Since the 1980 s, BTs have been employed in the treatment of various medical conditions, in particular syndromes involving muscular hyperactivity (strabismus, focal dystonia, spasticity, bruxism, myoclonus of the palate, etc.).13, 14 The subsequent decade saw the introduction of BTs as a treatment for autonomic cholinergic hyperactivity (focal hyperhidrosis, rhinorrhea, scialorrhea, Frey's syndrome, etc.) and for improving facial aesthetics, including resolution of a gummy smile.15, 16, 17, 18, 19

This article reports three cases of Botulinium neurotoxin used to temporarily resolve gingival excess in three female patients who had refused surgical treatment for this condition.

Section snippets

Case report 1

S.A. presented with a severe aesthetic discrepancy in the upper jaw following surgically-assisted expansion. In fact, in the median region of the premaxilla, a significant bone deficiency, probably due to post-surgical infection of the osseus callus, as well as consequent invagination of the gingiva and consolidated interincisive diastem, was evident.

The patient had decided to postpone periodontal surgical treatment of this aesthetic flaw, and asked us to resolve the upper gingival excess and

Case report 2

A.C. presented with a malocclusion associated with an excess of vertical growth of the maxilla and, in consequence, marked gingival exposure upon smiling. The patient immediately refused a combined orthodontic/surgical treatment as she felt her main problem was related to poor dental alignment. However, upon completion of orthodontic treatment to correct the malocclusion, the patient became increasingly unhappy with the gumminess of her smile and requested BT treatment to resolve this

Case report 3

The patient K.T. came to our clinic to seek treatment for her gummy smile. She advised us that her dental malocclusion had been corrected during adolescence and that she had consistently refused orthognathic surgery to deal with her gingival excess. However, at the time of consultation she was discontent with the aesthetics of her smile and desired to have it corrected via Botulinium toxin injection (Fig. 14, Fig. 15). Prior to treatment the gingival exposure was 4.5 mm (Fig. 16), but one month

Discussion

The use of Botox in Dentistry to resolve various conditions such as hypertonicity of the masseter, hemifacial spasm, bruxism and joint pain has to this date been amply documented.

More recently, however, it has been proposed as an orthodontic tool for the resolution of a gummy smile linked to hypertonicity of the elevator muscles of the upper lip. This technique, as demonstrated in the cases illustrated herein, is simple to carry out in an adequately equipped clinic and only slightly invasive to

Conflict of interest

The authors have reported no conflicts of interest.

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