An Approach for Gummy Smile Treatment Using Botulinum Toxin A: A Narrative Review of the Literature - Cureus

Methods

This nonfiction progressive a reappraisal of applicable published papers discussing the effect of Botox injection on the attraction of gummy smile. Several databases including PubMed and Google Scholar were utilized to stitchery the astir applicable articles. A hunt acceptable was applied to harvester a scope of keywords: botulinum toxin, Botox, and gummy smile. By utilizing this method, each the articles discussing the effect of Botox injection on the attraction of gummy smile were obtained. In the inclusion criteria, we included each the applicable studies discussing gummy grin and their attraction utilizing botulinum toxin. The papers that had a mediocre methodology and insufficient information were excluded. The archetypal screening revealed 62 papers. After applying our inclusion criteria, the astir applicable articles were selected and utilized successful our existent review. This survey was conducted by reviewing 28 papers related to the effect of Botox injection on the attraction of gummy smile.

Excessive gingival show (gummy smile)

Gingival show successful a definite measurement is considered aesthetically acceptable. However, much than 2-3 mm of gingival vulnerability during smiling is considered to beryllium a gummy grin [3,5,7,14]. The excessive gingival show tin beryllium owed to altered eruption of the teeth, hyperactive oregon abbreviated precocious articulator muscles, vertical maxillary excess, oregon dentoalveolar extrusion [5]. The incidence of gummy grin during smiling is astir 14% successful females and 7% successful males [8]. Rubin divided the grin into 3 types: the afloat denture grin that is related to the little depressors and precocious retractor muscles causing vulnerability of each teeth, the Mona Lisa grin that is related to the zygomaticus large muscle, and the canine grin that is associated with an elevation of the precocious articulator by the enactment of the levator labii superioris [8]. A classification by Mazzuco and Hexsel categorizes excessive gingival show based connected their country [9]. Four types of gummy smiles were presented: posterior, anterior, asymmetric, and mixed gummy smiles [4,8,15]. A posterior gummy grin is associated with mean vulnerability successful the anterior portion (<3 mm) and much than 3 mm of exposed gingiva posterior to the canines. An anterior gummy grin is associated with much than 3 mm of exposed gingiva betwixt the canine teeth owed to the levator labii superioris alaeque nasi muscles. An asymmetric gummy grin is associated with terrible vulnerability of the gingiva connected 1 tract owed to asymmetric contraction of either zygomatic oregon levator labii superioris alaeque nasi muscles. A mixed gummy grin is associated with terrible vulnerability of the gingiva successful some the posterior and anterior regions owed to a operation of zygomatic and levator labii superioris alaeque nasi muscle movement [4]. The diagnosis of a gummy grin clinically involves the measurement of the width of keratinized gingiva, frenal attachment, objective crown, vertical limits of the smile, overbite and overjet, anatomic crown length, and probing extent [1,5-7,14]. Skeletal, gingival, and muscular factors should beryllium evaluated portion treating gummy grin patients [3]. Radiographic introspection is utilized to find excessive vertical maxilla, protrusion of maxilla, and bony level [5]. The objection of the gingival show portion smiling and astatine remainder presumption is presented successful Figures 1-2 [5].

Botulinum toxic A (Botox)

Botulinum toxin was archetypal utilized successful the 1970s for the attraction of excessive musculus contraction and pain. This toxin is typically produced by the bacteria Clostridium botulinum [6,15]. Clostridium botulinum is an anaerobic and gram-positive rod bacterium with 8 serotypes and provides 7 botulinum neurotoxins (A-G) [3,4]. Botulinum toxin A (Botox) is chiefly utilized successful aesthetic and cosmetic practices. Three types of botulinum toxin A are present, which are called abobotulinum toxin A, incobotulinum toxin A, and onabotulinum toxin A. These are approved by the US Food and Drug Administration. Each of these has a antithetic potency [4]. Botulinum toxin is simply a minimally invasive attack for the attraction of gummy smiles particularly owed to hyperactive articulator muscles [5,16,17]. The effectiveness of botulinum toxin depends connected zinc arsenic each Botox molecule indispensable beryllium associated with a molecule of zinc successful bid to beryllium effectual [15]. Botulinum toxin causes chemic denervation of muscles successful the skeletal region, thus resulting successful a transitory simplification of musculus enactment without systemic manifestations. The injection of botulinum toxin intramuscularly splits the synaptosome-associated macromolecule resulting successful stopping the merchandise of acetylcholine (a neurotransmitter that activates gland secretion and musculus contraction) and permitting postsynaptic repolarization. This successful crook yields partial chemic denervation. The result is simply a relaxation of the elevating enactment of the articulator and a localized alteration successful the enactment of the elevator musculus [5,7,8,14,15,18]. Botox was confirmed by erstwhile studies to beryllium a suitable diagnostic method, arsenic good arsenic palliative treatment, for the attraction of gummy smiles [13]. Previous reports showed that Botox is effectual successful treating gummy smiles with a reversible effect, accelerated archetypal action, harmless application, debased risk, and straightforward and satisfactory outcome [7,9,17,19,20].

Indication and contraindication

In dentistry and maxillofacial country field, botulinum toxin has respective indications including improving excessive gingival show and facial wrinkles, tic and tremor treatment, and the absorption of symptom [11,18]. One of the communal indications of Botox attraction successful gummy grin patients is to trim the upward question of the articulator [12,13]. Changing articulator presumption and question with Botox is considered a suitable prime owed to the debased morbidity and easiness of usage [12]. Contraindications of utilizing Botox see patients taking calcium transmission blockers, large females oregon those who are lactating, patients taking aminoglycosides oregon cyclosporine, neuromuscular patients, and patients with hypersensitivity to saline oregon Botox [5]. The main reported regulation is the duration of these drugs, which lasts astir 4 to six months [12]. In lawsuit the diligent requires surgical intervention, Botox injection is not recommended since botulinum toxin lone offers a impermanent effect for the diligent [6].

Treatment readying and diligent selection

The main components of assessing gummy smiles are successful the afloat grin and astatine remainder positions. A afloat grin is divided into 2 phases, spontaneous and posed phases. Vertical maxillary excess with an excess gingival show astatine remainder is classified into 3 degrees: Degree 1 is considered 2-4 mm of gingival vulnerability and tin beryllium treated with orthodontic, prosthodontic, and periodontal treatments [12], 4-8 mm is considered arsenic grade 2, and grade 3 is associated with much than 8 mm [12]. Identifying the people musculus associated with a gummy grin is indispensable to find the nonstop attraction prime [4]. Gummy grin tin beryllium corrected utilizing Botox. However, the introspection of the muscles and the benignant of grin are indispensable for close attraction planning. The benignant of Botox used, circumstantial portion oregon muscle, training, method accuracy, and dosage should beryllium considered and evaluated during the attraction program signifier [7].

Different attraction approach

Patients often deficiency cognition and consciousness regarding Botox applications successful gummy smile; thus, the clinician should sermon each attraction options and their outcomes with the diligent [21]. To find the astir favorable attraction approach, erstwhile studies person suggested the classification of gummy smiles based connected their etiopathogenic factors. According to these studies, a precocious grin tin beryllium either dentoalveolar benignant owed to excessive vertical oregon sagittal maturation of the precocious jaw, dentogingival benignant that results from a alteration successful the mean way of dental eruption that leads to a simplification successful the objective crown, muscular type due to hyperactivity of the muscles surrounding the oral cavity, oregon mixed benignant that results from respective causal factors. Moreover, these studies reported that a bid of photometric and objective factors should beryllium considered from the frontal and lateral presumption during a diligent smiling [3].

The tallness of the cardinal incisors usually ranges from 9.5 to 11 mm based connected the patient's gender. In lawsuit the diligent exhibited excessive gingiva owed to abbreviated incisors, a referral to a periodontist is usually the adjacent measurement successful bid to dainty his smile. Thus, it is unacceptable to dainty a diligent with Botox injections if they endure from excessive gingival show owed to crown vulnerability [22]. Structural, dento-gingivo-labial, and occlusal parameters should beryllium besides evaluated during the attraction program phase. Structural parameters see the cutting incisal borderline of the incisors and the abstraction betwixt the subnasal point. Dento-gingivo-labial parameters see the interlabial gap, the magnitude of the precocious lip, and the magnitude of the coronal crown. Occlusal parameters see the inclination of the occlusal plane, overjet, and overbite [3]. Botox tin beryllium considered palliative successful lawsuit surgical attraction is needed, adjuvant attraction successful lawsuit determination is simply a request for further treatments specified arsenic orthodontic devices oregon articulator augmentation, oregon remedial successful lawsuit the origin of excessive gingival show is of muscular root [9].

Dose adjustment

Dosing tin beryllium adjusted depending connected the grade of correction desired [12]. The dosage of Botox injection differs from antheral to pistillate based connected the measurement of the articulator muscle. Typically, males necessitate precocious units of Botox compared to females to execute the aforesaid effect; this is owed to larger musculus measurement [5]. Duruel et al. recommended that the dose of botulinum toxin A per portion depends connected the severity of the gummy grin [4]. Initially, a maximum of 5 IU of onabotulinum toxin A tin beryllium injected and was stated to beryllium a harmless attack by the authors [4]. In correlation, Gong et al. suggested that the effect of the mean dose of Botox for the attraction of gummy grin depends connected the patient's sex and the severity of the gummy grin alternatively than the etiology [23]. Polo investigated botulinum toxin injections with 2.5 units successful the levator labii superioris and the levator labii superioris alaeque nasi to dainty the neuromuscular excessive gingival show [24]. The writer reported that it was satisfactory and effective; however, the effect was impermanent with a 5.2 mm mean gingival simplification [24].

Procedure

The attraction of gummy grin utilizing Botox tin beryllium divided into 3 types [7]. The corrective benignant is performed erstwhile the gummy grin is caused by musculus activity. The adjuvant benignant is performed erstwhile a operation of assorted causes are contiguous and supplementary treatments are indispensable specified arsenic orthodontic attraction oregon articulator augmentation. The palliative benignant is indicated whenever country is needed [7]. Numerous studies person suggested that botulinum toxin injection successful the elevator muscles of the precocious articulator is an effectual attraction attack for gummy grin [4,5,8,19]. A erstwhile survey conducted by Cengiz et al. illustrated that Botox injection mightiness beryllium effectual successful patients with accrued gingival vulnerability [6]. In addition, the levator labii superioris alaeque nasi and the orbicularis oris tin beryllium selected for Botox injections [6]. However, Cengiz et al. concluded that some groups evaluated showed a relapse imaginable erstwhile the 4th period was reached [6]. A survey by Makkeiah et al. aimed to measure the effectiveness of surgical articulator repositioning and botulinum toxin A for the attraction of gummy grin caused by hyperactive articulator based connected diligent restitution and the grin result [2]. The results showed that botulinum toxin A injection demonstrates amended results compared to surgery; successful addition, Botox has achieved the desired aesthetic request with much satisfactory and safer results compared to surgical articulator repositioning [2].

The Yonsei constituent is considered an effectual constituent for intramuscular Botox [1,5,25]. This constituent is positioned successful the mediate of a triangle shaped by the zygomaticus minor, levator labii superioris alaeque nasi, and levator labii superioris muscles [5]. Previous studies suggested that the injection of botulinum toxin A astatine the Yonsei constituent could beryllium a predictable and reliable attraction prime for antithetic types of gummy smiles [4,25]. Moreover, Suber et al. reported that the levator labii superioris alaeque nasi and levator labii superioris muscles are considered effectual sites for attraction utilizing Botox [8]. A caller objective proceedings by Costa et al. aimed to measure the effects of Botox attraction connected gummy grin reduction, diligent satisfaction, and musculus enactment [26]. The results showed that expanding the fig of injection points volition effect successful diligent satisfaction, gingival show reduction, and a persistent Botox effect. However, the wide strength of the result did not summation [26]. In addition, Aldhaher and Bede recommended the usage of a four-point technique for a amended result regarding the grade of restitution and objective measurements compared to a two-point technique [10]. Myotomy with articulator repositioning was reported to supply much stableness successful the agelong word compared to repositioning without myotomy. Yet, fewer patients considered the effect to beryllium satisfying [15]. Relevant objective studies discussing the usage of Botox for gummy grin attraction are presented successful Table 1.

The anterior gummy grin tin beryllium injected connected the lateral broadside to the helping of the nose. Posterior gummy grin injection should besides beryllium applied laterally to the helping of the nose; however, fractional of the dose should beryllium used, and the 2nd constituent should beryllium injected laterally by 2 cm to the first, peculiarly astatine the tragus enactment level [18]. A mixed gummy grin injection is done by utilizing some erstwhile techniques. However, a simplification of the dose by 50% connected the lateral broadside to the helping of the chemoreceptor is recommended [18]. Injection sites are presented successful Figure 3 [5].

Findings

A erstwhile systematic reappraisal by Zengiski et al. aimed to measure the longevity and effectiveness of the botulinum toxin for the attraction of excessive gingival show [27]. The writer reported that Botox is considered an alternate attraction attack for reducing gummy smiles chiefly successful cases that the gummy grin was up to 4 mm [27]. The effect of Botox is usually observed betwixt 1 and 2 weeks and lasts for 4 to six months [5,11]. A systematic reappraisal by Chagas et al. reported a important effect of Botox connected the attraction of gummy smiles [7]. In addition, the stableness was changeless until the eighth week [7]. However, the gingival show whitethorn reoccur aft 12 weeks [7]. Moreover, Razmaite et al. reported up to 5 mm simplification successful gummy grin pursuing Botox injections [1]. The writer reported that the champion result was observed aft 2 weeks of injection and the effect remains for astir 3 months oregon much [1]. Oliveira et al. besides reported a alteration successful the aboveground electromyography awesome amplitude aft 2 to 4 weeks post-Botox injections [28]. Follow-up aft 2 weeks pursuing Botox injections is presented successful Figure 4 [5].

Complications, broadside effects, and recommendations

Complications associated with Botox are reported to beryllium uncommon and astir apt temporary. Most of the guidelines urge 2.0-2.5 units to beryllium injected successful a peculiar muscular portion [12]. Botox re-injections should beryllium avoided successful lawsuit the clearance of the erstwhile effect has not worn disconnected wholly to forestall antibody enactment that tin effect successful unsatisfactory results. Zengiski et al. stated that aft 24 weeks of injection, the values instrumentality to their archetypal [27]. Botox injections are mostly considered harmless successful cases that quantity and method are measured correctly. Yet, constricted localized broadside effects were reported antecedently including inflammation, nervus palsy, pain, hematoma, infection, bruising, edema, and nonaccomplishment of musculus strength. Moreover, the inappropriate method of injection could pb to code difficulties, asymmetric unpleasant grin appearance, and drinking oregon chewing problems. Overdose mightiness effect successful ptosis oregon drooping of the articulator starring to sum of the teeth connected smiling [5].