Botox, Excessive Gingival Display

SHORT COMMUNICATION

Botulinum toxin type A in the treatment of excessive gingival display Mario Polo San Juan, Puerto Rico Purpose: One cause of excessive gingival display is the muscular capacity to raise the upper lip higher than average. Several surgical procedures have been reported to improve the condition, but surgery always involves risk and is costly. 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 or pain. This clinical pilot study was performed to determine whether BTX-A injections would reduce excessive gingival display. Material: Five subjects with excessive gingival display due to hyperfunctional upper lip elevator muscles were treated with BTX-A injections. Results: This treatment modality was effective, producing esthetically acceptable smiles in these patients. The improvements lasted 3 to 6 months. Conclusions: Injection with BTX-A at preselected sites is a novel, cosmetically effective, minimally invasive alternative for the temporary improvement of gummy smiles caused by hyperfunctional upper lip elevator muscles. (Am J Orthod Dentofacial Orthop 2005;127:214-8)

T

he display of excessive gingival tissue in the maxilla upon smiling has been called a “gummy smile,” a condition some consider esthetically displeasing. Some people with excessive gingival display are self-conscious or embarrassed about it, and some are psychologically affected.1 Although the incidence of excessive gingival display has not been established, it is fairly common. Etiologic factors can be skeletal, gingival, muscular, iatrogenic, or some combination of these. The literature contains many reports that address the skeletal problem of vertical maxillary excess2-6 and gingival problems related to delayed passive eruption.7-9 In his review of structural esthetic rules, Rufenacht10 referred to this condition. Robbins11 reported differential diagnosis and treatment of excessive gingival display. The muscular capacity to raise the upper lip higher than average (hyperfunctional muscle) can cause excessive gingival display.12 Upper lip elevator muscles include the levator labii superioris, levator labii superioris alaeque nasi, levator anguli oris, zygomaticus major, zygomaticus minor, and the depressor septi nasi. Several surgical procedures have been reported in the literature to correct a gummy smile caused by hyperfunctional upper lip elevator muscles (mostly the levator labii superioris muscles). Rubinstein and Medical faculty orthodontist, Department of Surgery, San Jorge Children’s Hospital/Plastic and Reconstructive Center, San Juan, Puerto Rico. Reprint requests to: Dr Mario Polo, 702 La Torre de Plaza, 525 F.D. Roosevelt Ave, San Juan, Puerto Rico 00918-0702; e-mail, [email protected]. Submitted, May 2004; revised and accepted, September 2004. 0889-5406/$30.00 Copyright © 2005 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2004.09.013

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Kostianovsky13 described a procedure whereby an elliptical portion of gingiva and buccal mucosa was excised and the borders approximated and sutured together. Litton and Fournier14 referred to “muscle detachment from the bony structures above” to bring the lip down. Miskinyar15 used a different surgical technique to treat 27 patients, including 7 who had relapsed after being treated with the Rubinstein and Kostianovsky technique. Miskinyar claimed only “a minor success rate, and even complete disappointment with previous techniques.” In his new technique, he performed myectomy and partial resection of the levator labii superioris muscles; 1 or both of the bellies of the muscles were amputated 1.0 to 2.0 cm at their junction with the orbicularis oris muscle. No reference was made to a skeletal etiology for the problems, as stated by Sullivan,16 and no follow-up time was discussed. Ellenbogen17 reported that resection of the levator labii superioris is short-lived, with the gummy smile returning within 6 months. He advocated placing a spacer, either nasal cartilage or prosthetic material, between the stumps to prevent the muscles from being reunited and again hyperelevating the lip. Miskinyar18 stated that patients he followed for as long as 8 years showed no recurrence or disappointing results,15 but he also pointed out possible disadvantages with the spacer technique: migration of the spacer to an undesired site and the muscle ends reuniting, rejection of a foreign body (in the case of prosthetic spacers), and the need for a second surgical procedure if nasal cartilage is used. Rees and LaTrenta19 described a camouflage procedure through the columella, whereby a subperios-

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teal dissection of the upper lip elevators was performed. Ezquerra et al20 presented a multidisciplinary approach for treating a high smile line with excessive gingival display: either LeFort I osteotomy or gingival and alveolar bone remodeling surgery, or a modified (intraoral) camouflage procedure as described by Rees and LaTrenta,19 or a combination of the latter 2. A nonsurgical alternative for reducing excessive gingival display caused by muscle hyperfunction would be advantageous. Botulinum toxin has been under clinical investigation since the late 1970s for the treatment of several conditions associated with excessive muscle contraction or pain.22 Botulinum toxin is produced by the anaerobic bacterium Clostridium botulinum. There are 8 different serotypes of botulinum toxin. Type A (BTX-A) is the most potent and the most commonly used clinically. Botox (Allergan, Irvine, Calif) is a purified BTX-A isolated from the fermentation of C botulinum. It is a stable, sterile, vacuum-dried powder that is diluted with saline solution without preservatives. BTX-A weakens skeletal muscles by cleaving the synaptosome-associated protein SNAP-25, thus blocking the release of acetylcholine from the motoneuron and enabling the repolarization of the postsynaptic terminal. As a result, the muscular contraction is blocked. The production of acetylcholine is not affected by this blockade of the neuromuscular transmission. The effects last 3 to 6 months, although some investigators have reported a longer duration in patients exposed over a prolonged period of time.21 BTX-A has been used to treat strabismus,23 cervical dystonia,24 blepharospasm and hemifacial spasm,25 hyperfunctional larynx,26 juvenile cerebral palsy,27 spasticity,28 pain and headache,29 occupational dystonia and writer’s cramp,30 temporomandibular disorders,31 myofacial pain,32 and oromandibular dystonia and bruxism,33 and several other conditions. Since 1987, BTX-A has been widely used for the cosmetic treatment of hyperfunctional facial lines.34 The purposes of this pilot study were to determine whether BTX-A could also be used in patients with hyperfunctional upper lip elevator musculature to correct a gummy smile and to establish the optimal minimal dose of BTX-A needed to obtain cosmetically pleasing results. MATERIAL AND METHODS

Twelve women with excessive gingival display were screened, and 5 were selected for this study. They ranged in age from 16 to 23 years. Cephalometric analysis was performed to determine whether the gummy smile was skeletal (ie, vertical maxillary excess). Periodontal evaluation was performed to rule out

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delayed passive eruption leading to excessive gingival display. These patients had a history of fairly good oral hygiene, although mild gingivitis was acceptable. Some were receiving active orthodontic treatment. Information about the procedure, its possible benefits, risks, and side effects, and the expected duration of the results, if any, was given in detail to the patients and the parents of the minors verbally and in writing. All agreed to participate. Written informed consent was obtained. The study was divided into 3 phases. At the beginning of phase I, extraoral photographs were taken, including a close-up photograph with a ruler placed vertically at the facial midline while the patient was smiling (Fig 1). The spot where the superior portion of the ruler barely touched the midline of the columella’s most inferior portion at the nasolabial junction was designated reference point 1 (RP1). The ruler passed through the middle of the philtrum and extended inferiorly into the midline of the chin. The incisal edge of the maxillary right central incisor along its mesial surface at the midline was designated reference point 2 (RP2). The distance between the reference points was constant for each subject when the full-smile photographs were taken; minor variations (1.0 mm or less) between RP1 and RP2 measurements taken before and after the procedure were compensated for when they were recorded. Injections were made intramuscularly under electromyographic guidance.35 BTX-A was diluted by adding 4.0 mL of 0.9% normal saline solution without preservatives to 100 U of vacuum-dried C botulinum type A neurotoxin complex, according to the manufacturer’s dilution technique. This resulted in a 2.5 U/0.1 mL dose. After carefully reviewing the literature for small muscle dosage, a dose of 1.25 U per muscle site per side was selected as a baseline to start the study. Under sterile conditions, 1.25 U per side was injected in both the right and left levator labii superioris and levator labii superioris alaeque nasi muscles (LLS), and an additional 1.25 U per side at the overlap areas of the levator labii superioris and zygomaticus minor muscles (LLS/ZM). Aspiration before BTX-A injection was done to avoid involuntary deposition of the toxin into the facial arteries. During this phase, patient 1 received an additional 1.25 U per side at the origin of the depressor septi nasi muscle at the orbicularis oris muscle (OO), 2 to 3 mm inferior to the nostrils and 2 to 3 mm from the midline. The patients were clinically evaluated 1 week, 2 weeks, 4 weeks, and 16 weeks postoperatively. During the first evaluation, they were asked to report any adverse reactions or side effects associated with the procedure. They also reported how long after the procedure they started noticing the effects on their

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Fig 1. Drawing with landmarks and close-up smiling photos with ruler at facial midline.

upper lips and smiles. During the 2-week evaluation, in addition to reviewing again for adverse reactions and onset of changes, subjects were evaluated to determine whether the results obtained were sufficient or whether additional muscular weakness by reinjection was desirable. Phase II of the study began 1 month later. After determining 2 weeks postoperatively that additional injections could enhance the results, it was decided to inject the LLS and the LLS/ZM with a supplemental dose of BTX-A. All patients agreed to undergo this second session. The subjects received 0.625 U per side at the LLS/ZM sites and either 1.25 U or 0.625 U at the LLS sites. The latter was determined by clinical evaluation of each patient’s results observed from phase I. The patients were clinically evaluated 2 weeks, 4 weeks, and 16 weeks postoperatively after the phase II injection. Facial photographs were obtained at the 2-week postoperative visit. During the 16-week follow-up visit, the patients were evaluated for evidence of lasting or remaining effects. Phase III of the study followed a similar protocol, except that all patients received 2.5 U injections per side at the LLS and LLS/ZM sites. Patients 1 and 4 also received 1.25 U per side at the OO site described above. They had the greatest amount of upper lip elevation near the philtrum. They were then evaluated 2 weeks, 4 weeks, and 16 weeks postoperatively. Photographs were obtained at the 2-week postoperative visit. One patient requested an additional treatment. She received 1.5 U per side at LLS and LLS/ZM sites and 1.25 U per side at OO sites 3 months after the phase III injection. She received these lower doses because she was experiencing residual effects from her last BTX-A administration, but she nevertheless wanted to enhance the results previously achieved. RESULTS

The results of this pilot study were analyzed both subjectively, by clinical evaluation of the gummy

smile, and objectively, with pre- and postoperative photographs (Fig 2). The following measurements (called A, B, and C) were recorded: A: RP1 to superior border of upper lip vermilion; B: RP1 to inferior border of upper lip vermilion; and C: inferior border of upper lip vermilion border to junction of the gingiva with the maxillary right central incisor crown along its own midline. All 5 patients began to show improvement approximately 10 days after the injections. After 14 days, results were definitely observed. The pre- and postoperative measurements were recorded and compared. At 2 weeks after injection in phases II and III, all 5 patients had a mean increase of measurements A and B of 4.20 mm and a mean decrease of measurement C of 4.20 mm (Table I). The effective increase in upper lip length upon smiling was 131%, 120%, 124%, 117%, and 129% (mean, 124.2%) for patients 1 through 5, respectively. Gingival exposure went from 4.0 mm to 0 mm for patients 1 and 3, from 4.0 mm to 1 mm for patient 4, and from 5.0 mm to 0.0 mm for patients 2 and 5. There was no significant difference in the measurements between phase II and phase III. Patients 2 and 5 showed the greatest improvement, as determined by the measurements, followed by patient 1. Patients 1 and 4 received the injection at the OO site; however, patients 2 and 5 showed the greatest amount of improvement. DISCUSSION

All patients were pleased with the results. No side effects (infection, bruising, edema, or loss of muscle strength) were reported or observed. One patient reported mild pain during the injection procedure. The effect began to be noticeable approximately 10 days after injection, with the maximum noticeable effect about 14 days after injection. This effect was reported to be progressive but also reversible, lasting 3 to 6

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Table.

Linear measurements: phase III Measurement (mm) A

B

C

⌬A (mm)

⌬C (mm)

8.0 12.0 9.0 13.0 12.0 16.0 12.0 15.0 9.0 14.0

5.0 5.0 6.0 6.0 5.0 5.0 6.0 6.0 8.0 8.0

4.0 0.0 5.0 0.0 4.0 0.0 4.0 1.0 5.0 0.0

4.0

⫺4.0

5.0

⫺5.0

4.0

⫺4.0

3.0

⫺3.0

5.0

⫺5.0

Patient no. 1 Preoperative Postoperative 2 Preoperative Postoperative 3 Preoperative Postoperative 4 Preoperative Postoperative 5 Preoperative Postoperative

See text for definitions of measurements A, B, and C.

months. The patients received a supplemental dose 1 month after the initial baseline dose in phase I. The results obtained from phase III were highly acceptable, and that dosage could be the optimal dose for achieving the expected results. Clinical judgment should always be exercised when selecting the injection sites. In severe cases, injecting at the OO site should be clinically considered, because the depressor septi nasi muscle, also associated with elevating the upper lip near the midline, inserts into the fibers of the OO muscle. The depressor septi nasi muscle thus has a vertical pull component on the OO. The zygomaticus major muscle was not included in this study but will be in a subsequent study now underway. Although surgical techniques have been reported in the literature, they are not routinely used to treat hyperfunctional upper lip elevator muscles resulting in a short upper lip and a concomitant gummy smile. Most of the surgical correction currently used seems to be LeFort I maxillary osteotomies with impaction for skeletal vertical maxillary excess and gingivectomies for delayed passive dental eruption with excessive gingival display. Because BTX-A is used frequently for the temporary correction of perioral rhytides, care should be taken when injecting these anatomical areas in patients with hypotonic, flaccid lips to avoid further muscle weakening and an esthetically unacceptable smile because of excessive soft tissue covering the smile line. CONCLUSIONS

Injection with BTX-A provides effective, minimally invasive, temporary improvement of gummy

Fig 2. Pretreatment and posttreatment photographs of study subjects.

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smiles for patients with hyperfunctional upper lip elevator muscles. The ideal dosage might be 2.5 U per side at the LLS, 2.5 U per side at the LLS/ZM sites, and 1.25 U per side at the OO sites. Future studies are needed to assess this treatment in a much larger sample. I thank Gishlaine Alfonso, MD, neurologist, for her teaching and training of the electromyographically guided injection technique of BTX-A. REFERENCES 1. Flanary C. The psychology of appearance and the psychological impact of surgical alteration of the face. In: Bell WH, editor. Orthognathic and reconstructive surgery. Volume 1; 1st ed. Philadelphia: W. B. Saunders; 1992. p. 2-21. 2. Garber DA. Problems of the lip line: the gummy smile. In: Bell WH, editor. Orthognathic and reconstructive surgery. Volume 1; 1st ed. Philadelphia: W. B. Saunders; 1992. p. 252-61. 3. Fish LC, Wolford LM, Epker BN. Surgical-orthodontic correction of vertical maxillary excess. Am J Orthod 1978;73:241-57. 4. Schendel SA, Eisenfeld J, Bell WH, Epker BN, Mishelerich DJ. The long face syndrome: vertical maxillary excess. Am J Orthod 1976;70:398-408. 5. Bell WH. Correction of maxillary excess by anterior maxillary osteotomy. A review of three basic procedures. Oral Surg Oral Med Oral Pathol 1977;43:323-32. 6. Poulton DR. Surgical orthodontics: maxillary procedures. Angle Orthod 1976;46:312-31. 7. Coslet JG, Vanarsdall RL, Weisgold A. Diagnosis and classification of delayed passive eruption of dentogingival junction in the adult. Alpha Omegan 1977;70:24-8. 8. Conley RS, Legan HL. Correction of severe vertical maxillary excess with anterior open bite and transverse deficiency. Angle Orthod 2002;72:265-74. 9. Garber DA, Salama MA. The aesthetic smile: diagnosis and treatment. Periodontol 2000 1996;11:18-28. 10. Rufenacht CR. Structural esthetic rules. In: Rufenacht CR, editor. Fundamentals of esthetics. Chicago: Quintessence; 1990. p. 67-135. 11. Robbins JW. Differential diagnosis and treatment of excess gingival display. Pract Periodontics Aesthet Dent 1999;11:265-72. 12. Peck S, Peck L, Kataja M. The gingival smile line. Angle Orthod 1992;62:91-100. 13. Rubinstein A, Kostianovsky A. Cosmetic surgery for the malformation of the laugh: original technique. Prensa Med Argent 1973;60:952. 14. Litton C, Fournier P. Simple surgical correction of the gummy smile. Plast Reconstr Surg 1979;63:372-3. 15. Miskinyar SA. A new method for correcting a gummy smile. Plast Reconstr Surg 1983;72:397-400. 16. Sullivan WG. Correspondence and brief communications. Plast Reconstr Surg 1984;73:697. 17. Ellenbogen R. Correspondence and brief communications. Plast Reconstr Surg 1984;73:697-98. 18. Miskinyar SA. Correspondence and brief communications. Plast Reconstr Surg 1984;73:697. 19. Rees TD, LaTrenta GS. The long face syndrome and rhinoplasty. Persp Plast Surg 1989;3:116. 20. Ezquerra F, Berrazueta MJ, Ruiz-Capillas A, Sainz-Arregui J. New approach to the gummy smile. Plast Reconstr Surg 1999; 104:1143-50.

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