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Authors : Dr. Mahajan Shally , Dr. Srivastava Vipul , Dr. Sharma Shourya.

Abstract

Gummy smile has been one of the prime concerns in facial esthteics as well as the patients undergoing dental treatment. There are several etiologic factors that include skeletal, gingival and muscular that works in combination to contribute to this condition.The current article is a case report of a patient with gummy smile treated with a non invasive intervention using Botulinum toxin type A.

Key words: Botulinum toxin, Lip elevator muscles, Gummy smile, Non invasive , Neurotoxin

Introduction

One of the common reasons of patient seeking treatment in orthodontics is the excessive gingival display or appearance of gummy smile. Relationships between three components of teeth, lip framework, and the gingival scaffold determine the esthetic appearance of smile.1 A beautiful smile would be ideally a perfect set of teeth along with pleasing peri-oralfacial esthetics.

The objective of lip repositioning is to minimize the excessive gingival display by limiting the retraction of the elevator smile (Levator labii superioris , Levator anguli, Orbicularis oris, Zygomaticus minor).2

The treatment options depends on etiology and may range from invasive ( surgery- gingivectomy, muscle resection, orthognathic surgery) to a non invasive (orthodontic intrusion, diminish the activity of hyperfunctional lip elevator muscle) approach.

The surgical procedures may lead to frequent relapse and undesirable side effects such as scar contraction. Hence, a minimally invasive treatment modality that can serve as a substitute for the surgical procedure, i.e., the use of botulinum toxin (BTX) has been suggested. This toxin acts by cleaving the synaptosomal-associated protein (SNAP-25) and inhibiting the release of acetylcholine, thus preventing muscle contraction. Among the seven serologically distinct types of botulinum neurotoxin,type A (BTX-A) appears to be the most potent and is most often used clinically.3

Botulinum toxin type A (BTX-A) (Botox; Allergan, Irvine, Calif) has been studied since the late 1970s for the treatment of several conditions associated with excessive muscle contraction. Botulinum toxins or Botox® is available in a freeze-dried powder that clumps at the bottom of the vial. The action of Botox is selective muscle denervation.

Woo-Sang Hwang4 proposed a safe and reproducible injection point (Yonsei point )for botulinum toxin-A (BTX-A) as a supplementary method for the treatment of gummy smile, as determined by assessment of the morphologic characteristics of three lip elevator muscles.

Yonsei point( Figure 1 )is located at the centre of the triangle formed by:
  1. Levator labii superioris [LLS],
  2. Levator labii superioris alaeque nasi [LLSAN], and 
  3. Zygomaticus minor [Zmi].

Effect of Botox is seen within 5-10 days and lasts about 6 months, with a range of 4 to 8 months, at which time the patient can return to repeat the process.

Case report:

A 30 year old female patient presented with a chief complaint of excessive gingival display on smiling. She wanted to minimize her gingival display but was reluctant to get any surgical intervention and wanted to go ahead with the non invasive treatment methodology. On general physical examination patient did not present with any relevant medical history and all her vital stats were within the normal range. On clinical examination, patient revealed no lip incompetency or muscle strain with her lips reposed. She showed adequate upper incisor exposure at rest. On smiling, more than 5-6 mm of gingival display was seen (Figure 2). Hence, the clinician diagnosed that her gummy smile was due to hyperactive lip elevator muscles.
 
Figure 1. Yonsei Point Figure 2. Extra oral picture of patient showing the gingival display while smiling


An informed consent was obtained after the discussion of all the other alternative treatment modalities, benefits and possible complications of treatment the condition with botulinum toxin.
 
Figure 3. a).Prepration of Botulinum toxin b) Injection Point c) Site of Injection


BTX-A (Botox; Allergan Inc, Westport, Ireland), supplied as a freeze-dried powder of 100 U, was reconstituted with 2 mL normal saline (0.9%) solution to make a 5.0 U/0.1 mL dose according to the manufacturer’s instructions( Figure 3 a),and 2.5 U were injected bilaterally at each Yonsei point( Figure1, 3 b, 3c).The patient was instructed not to rub on the injected area and recalled after 10 days. After 10 days, the gingival display was reduced to 2 mm along with symmetric elevation of the upper lip observed clinically(Figure 4).
 
Figure 4. Post treatment after 10 days


There were no side effects reported such as infection or edema. The patient was recalled after 6months to check for the fading effects of BTX and a mild relapse was noted( Figure 5).The patient was advised to go for another sitting requiring the administration of botulinum toxin at the same area but the patient was happy with her present facial esthetics .
 
Figure 5. Post treatment after 6 months


Discussion

The smile itself and the aesthetics of the smile are influenced by 3 components: teeth, gums, and lips. An attractive smile depends on the proper proportion and arrangement of these 3 elements. The upper lip should symmetrically expose up to 3 mm of the gum and the gum line must follow the contour of the upper lip. The exposure of more than 3 mm of the gum during the smile is known as gingival or gummy smile. For some patients, gummy smile represents an aesthetic disorder. Hulsey5 noted that the most attractive smiles were those in which the upper lip rested at the height of the gingival margin of the maxillary incisor.

Tjan et al6 reported gender differences in the smile line. In men, the authors report that the low smile line is predominant (2.5:1), whereas high smile lines are predominant in women (2:1).

Botulinum is derived from the Latin word botulus, meaning sausage, and botulism was originally called sausage poisoning because it occurred after ingestion of poorly prepared blood sausage.

Justinus Kerner (1786-1862) was the first to describe the features of botulism.7

Botulinum toxin is synthesized by C. botulinum, C. butyricum, and C. baratii, all of which areanaerobic spore forming bacilli. The spores are heat resistant, and they can germinate to producetoxin in the appropriate environment of anaerobic conditions, low acidity, and liquid medium, as found in some foods. The toxin is ingested and absorbed through the gastrointestinal tract into the systemic circulation.

In a significant number of patients, reduced gum exposure after several applications of botulinum toxin has been noticed even after the effect of the drug has declined. This fact can be explained by the decrease in muscle strength that is likely to occur after several consecutive applications of botulinum toxin for any particular indication making it last for a longer period of time. It is important that the physician identify such cases, in subsequent applications, and reduce the dose to avoid an exaggerated effect.8

Drug Interaction Drugs that may alter the effects of Botulinum toxin include: aminoglycosides (gentamycin), cyclosporine, D-penicillamine, muscle relaxants (cu-rare-type nondepolarizing blockers, succinylcholine), aminoquinolones, quinidine, magnesium sulfate, and lincosamide.9

Contraindication10 include patients who are:
  • Psychologically unstable or who have questionable motives and unrealistic expectations.
  • Dependent on intact facial movements and expressions for their livelihood (e.g. actors, singers, musicians and other media personalities).
  • Afflicted with a neuromuscular disorder (e.g. myasthenia gravis, Eaton-Lambert syndrome).
  • Allergic to any of the components of BTX-A or BTX-B (i.e. BTX, human albumin, saline, lactose and sodium succinate).
  • Taking certain medications that can interfere with neuromuscular impulse transmission and potentiate the effects of BTX (e.g. aminoglycosides, penicillamine, quinine, and calcium blockers).
  • Pregnant or lactating (BTXs are classified as pregnancy category C drugs).

The common adverse effects are of limited duration and usually, localized and not of a serious nature.
  • Mild stinging, burning or pain with injection
  • Edema around injection site
  • Erythema around injection site
  • Mild headache, localized and transient Technique dependent
  • Ecchymosis lasting 3 to 10 days
  • Asymmetry
  • Oral incompetence and asymmetric smile
  • Lack of intended cosmetic effect Rare and idiosyncratic
  • Numbness and paresthesias( localized and transient)
  • Focal tonic movements (twitching)
  • Mild nausea and occasional vomiting
  • Mild malaise and myalgias (localized and generalized)

Rare adverse effects of longer duration that can be serious and are not technique dependent :
  • Immediate hypersensitivity reactions
  • Urticaria
  • Dyspnea
  • Soft tissue edema
  • Anaphylaxis

Conclusion 

Botulinum toxins are a boon to our dental field. This therapy is not only conservative, but also a minimally invasive treatment approach that can expand our therapeutic and treatment options for the benefit of our patients.

Hands-on training from a renowned academy is absolutely essential in learning the correct technique and protocol of how to use this versatile toxin for the maximum benefitto our patients and dental fraternity . With proper training, dentists are usually more proficient than any of these other healthcare professions in providing these treatments to patients, both for dental and cosmetic needs. It is time to broaden our horizons as a profession and use all of the tools available to us.

ACKNOWLEDGEMENT

Authors would like to thank Dr. Surbhi Kakar, owner “Sense of Smile Clinic” New Delhi, for helping us to carry out this Case Report

References:
  1. Garber DA, Salama MA. The aesthetic smile: diagnosis and treatment. Periodontol 2000. 1996;11:18–28.
  2. Hu KS, Yang SJ, Kwak HH, Park HD, Youn KH, Jung HS, Kim HJ. Location of the modiolous and the morphologic variations of the risorius and zygomaticus major muscle related to the facial expression in Koreans. KoreanJ PhysAnthropol. 2005;18:1–11.
  3. Polo M. Botulinum toxin type A in the treatment of excessive gingival display. Am J Orthod Dentofacial Orthop. 2005;127: 214–218; quiz 261.
  4. Woo-Sang Hwang: Surface Anatomy of the Lip Elevator Muscles for the Treatment of Gummy Smile Using Botulinum Toxin. Angle Orthod.2009; 79:70–77.
  5. 16. Mackley RJ. An Evaluation of smiles before and after orthodontic treatment. Angle Orthod. 1993; 63(3): 183-189.
  6. Tjan AH, Miller GD, The JG. Some esthetic factors in a smile. J Prosthet Dent. 1984; 51(1):24-28.
  7. Mahajan S, Srivastava V. Botulinum Toxin: a Poison Transformed into a Versatile Tool. Eur Jour Of esthetic Dentistry. Guest Editorial. 2010;5(4) :327.
  8. Mazzuco and Hexsel: Gummy smile and botulinum toxin: A new approach based on the gingival exposure area. J AM Acad Dermatol, vol 63, no 6, 1042-1051.

More References Are Available On Request