Botulinum toxin type A for gummy smile
Anatomical targeting, protocol variability, and reproducible outcome measurement
DOI:
https://doi.org/10.67463/2pcxgv61Keywords:
botulinum toxin type A, excessive gingival display, Yonsei point, facial measurement, three-dimensional imaging, treatment reproducibilityAbstract
Objective: To critically reassess the use of botulinum toxin type A (BoNT/A) for gummy smile, with emphasis on anatomical targeting, protocol variability, and the conditions required for reproducible outcome measurement.
Data sources: Literature addressing etiologic phenotyping of gummy smile, elevator-muscle anatomy, BoNT/A formulation and preparation, targeted clinical application, and digital approaches to image-based outcome capture.
Eligibility criteria: Studies and technical sources were prioritized when they directly informed five linked domains: phenotype selection, anatomical rationale, product handling, delivery variables, and the reliability of endpoint documentation.
Methods of synthesis: Critical narrative review integrating anatomical, clinical, pharmaceutical, and measurement-oriented evidence relevant to the translational interpretation of BoNT/A therapy for gummy smile.
Main findings: The literature supports temporary gingival-display reduction in selected muscular cases and offers a credible anatomical rationale for targeting the Yonsei region. However, universality of the point is not supported. Morphometric variation, heterogeneous smile-task architecture, non-equivalent product preparation, and incompletely reported dose-volume-depth relationships remain major interpretive barriers.
Conclusion: BoNT/A remains a defensible minimally invasive option for compatible muscular etiologies, but the field will mature only when anatomical targeting, product handling, dose-volume-depth architecture, smile-task definition, and digitally auditable outcome measurement are integrated within one reproducible protocol.
References
Lacy DB, Tepp W, Cohen AC, DasGupta BR, Stevens RC. Crystal structure of botulinum neurotoxin type A and implications for toxicity. Nat Struct Biol. 1998;5(10):898-902. https://doi.org/10.1038/2338. DOI: https://doi.org/10.1038/2338
Gregory KS, Acharya KR. A comprehensive structural analysis of Clostridium botulinum neurotoxin A cell-binding domain from different subtypes. Toxins (Basel). 2023;15(2):92. https://doi.org/10.3390/toxins15020092. DOI: https://doi.org/10.3390/toxins15020092
Hada S, Lee JC, Lee EC, Ji S, Kim NA, Jeong SH, et al. Dissociation mechanics and stability of type A botulinum neurotoxin complex by means of biophysical evaluation. J Pharm Investig. 2022;52:453-63. https://doi.org/10.1007/s40005-022-00570-2. DOI: https://doi.org/10.1007/s40005-022-00570-2
Ellis K, Thach T, Gallagher CJ. Biochemical stability and microbial control of reconstituted daxibotulinumtoxinA-lanm for injection. Toxins (Basel). 2023;15(12):683. https://doi.org/10.3390/toxins15120683. DOI: https://doi.org/10.3390/toxins15120683
Polo M. Botulinum toxin type A in the treatment of excessive gingival display. Am J Orthod Dentofacial Orthop. 2005;127(2):214-8. https://doi.org/10.1016/j.ajodo.2004.09.013. DOI: https://doi.org/10.1016/j.ajodo.2004.09.013
Polo M. Botulinum toxin type A (Botox) for the neuromuscular correction of excessive gingival display on smiling (gummy smile). Am J Orthod Dentofacial Orthop. 2008;133(2):195-203. https://doi.org/10.1016/j.ajodo.2007.04.033. DOI: https://doi.org/10.1016/j.ajodo.2007.04.033
Mazzuco R, Hexsel D. Gummy smile and botulinum toxin: a new approach based on the gingival exposure area. J Am Acad Dermatol. 2010;63(6):1042-51. https://doi.org/10.1016/j.jaad.2010.02.053. DOI: https://doi.org/10.1016/j.jaad.2010.02.053
Cengiz AF, Goymen M, Akcali C. Efficacy of botulinum toxin for treating a gummy smile. Am J Orthod Dentofacial Orthop. 2020;158(1):50-8. https://doi.org/10.1016/j.ajodo.2019.07.014. DOI: https://doi.org/10.1016/j.ajodo.2019.07.014
Costa AB, Romansina D, Ramalho J, Pereira P, Tedesco TK, Morimoto S, et al. Botulinum toxin A in the management of a gummy smile: a clinical controlled preliminary study. Aesthet Surg J. 2022;42(4):421-30. https://doi.org/10.1093/asj/sjab342. DOI: https://doi.org/10.1093/asj/sjab342
Chagas TF, Almeida NV, Lisboa CO, Ferreira DMTP, Mattos CT, Mucha JN. Duration of effectiveness of botulinum toxin type A in excessive gingival display: a systematic review and meta-analysis. Braz Oral Res. 2018;32:e30. https://doi.org/10.1590/1807-3107bor-2018.vol32.0030. DOI: https://doi.org/10.1590/1807-3107bor-2018.vol32.0030
Zengiski ACS, Basso IB, Cavalcante-Leao BL, Stechman-Neto J, Santos RS, Guariza-Filho O, et al. Effect and longevity of botulinum toxin in the treatment of gummy smile: a meta-analysis and meta-regression. Clin Oral Investig. 2022;26(1):109-17. https://doi.org/10.1007/s00784-021-04223-w. DOI: https://doi.org/10.1007/s00784-021-04223-w
Rojo-Sanchis C, Montiel-Company JM, Tarazona-Alvarez B, Haas-Junior OL, Peiro-Guijarro MA, Paredes-Gallardo V, et al. Non-surgical management of the gingival smile with botulinum toxin A: a systematic review and meta-analysis. J Clin Med. 2023;12(4):1433. https://doi.org/10.3390/jcm12041433. DOI: https://doi.org/10.3390/jcm12041433
Wang XY, Zou YR, Yuan MN, Huang HY, Han XF, Gong X. Dose and injection site of botulinum toxin type A for gummy smile management: a systematic review and bibliometric analysis. Toxicon. 2024;249:108058. https://doi.org/10.1016/j.toxicon.2024.108058. DOI: https://doi.org/10.1016/j.toxicon.2024.108058
Hwang WS, Hur MS, Hu KS, Song WC, Koh KS, Baik HS, et al. Surface anatomy of the lip elevator muscles for the treatment of gummy smile using botulinum toxin. Angle Orthod. 2009;79(1):70-7. https://doi.org/10.2319/091407-437.1. DOI: https://doi.org/10.2319/091407-437.1
Duruel O, Ataman-Duruel ET, Tozum TF, Berker E. Ideal dose and injection site for gummy smile treatment with botulinum toxin-A: a systematic review and introduction of case study. Int J Periodontics Restorative Dent. 2019;39(4):e167-73. https://doi.org/10.11607/prd.3580. DOI: https://doi.org/10.11607/prd.3580
Al Wayli H. Versatility of botulinum toxin at the Yonsei point for the treatment of gummy smile. Int J Esthet Dent. 2019;14(1):86-95. PubMed: https://pubmed.ncbi.nlm.nih.gov/30714057/
Gupta N, Kohli S. Evaluation of a neurotoxin as an adjunctive treatment modality for the management of gummy smile. Indian Dermatol Online J. 2019;10(5):560-3. https://doi.org/10.4103/idoj.IDOJ_365_18. DOI: https://doi.org/10.4103/idoj.IDOJ_365_18
Booysen B, Baron RH, Uys A. Establishing standards for Yonsei point in a White South African population for the treatment of gummy smile. Clin Exp Dent Res. 2023;9(3):455-63. https://doi.org/10.1002/cre2.735. DOI: https://doi.org/10.1002/cre2.735
Gong X, Tang HN, Zhang AR, Wang Z, Tang ZH, Han XF, et al. Application of botulinum toxin at the Yonsei point for the treatment of gummy smile: a randomized controlled trial. Plast Reconstr Surg. 2024;153(4):711e-21e. https://doi.org/10.1097/PRS.0000000000010623. DOI: https://doi.org/10.1097/PRS.0000000000010623
Picelli A, Tamburin S, Di Censo R, Smania N, Filippetti M. Does the diffusion profile differ between botulinum toxin type A formulations? Implications for the management of post-stroke spasticity. Toxins (Basel). 2024;16(11):480. https://doi.org/10.3390/toxins16110480. DOI: https://doi.org/10.3390/toxins16110480
Gardner A, Sneller M, Tepp WH, Barbieri JT, Pellett S. Botulinum neurotoxin Light Chain/A1 uses fast synaptic vesicle cycling to cleave plasma membrane-bound SNAP-25. Commun Biol. 2025;8:1383. https://doi.org/10.1038/s42003-025-08633-4. DOI: https://doi.org/10.1038/s42003-025-08633-4
Wan J, Yoon SE, Cartier H, Garson S, Yi KH. The Yonsei point: a precision approach to gummy smile correction with botulinum neurotoxin. J Craniofac Surg. 2025;36(7):e852-5. https://doi.org/10.1097/SCS.0000000000011253. DOI: https://doi.org/10.1097/SCS.0000000000011253
Ayaz I, Shaheen E, Aly M, Shujaat S, Gallo G, Coucke W, et al. Accuracy and reliability of 2-dimensional photography versus 3-dimensional soft tissue imaging. Imaging Sci Dent. 2020;50(1):15-22. https://doi.org/10.5624/isd.2020.50.1.15. DOI: https://doi.org/10.5624/isd.2020.50.1.15
Gonçalves L, Silva D, Galdino K. Mapping botulinum toxin injection sites and automated unit totalization in orofacial harmonization: a session-based web module for standardized, traceable clinical imaging. Derecho y Cambio Social. 2026;23(88):1-19. https://doi.org/10.54899/dcs.v23i88.4842. DOI: https://doi.org/10.54899/dcs.v23i88.4842
Silva D, Gonçalves L, Galdino KS. Gummy smile modulation with onabotulinumtoxinA at the Yonsei point after aesthetic ceramic rehabilitation: a case report. Derecho y Cambio Social. 2026;23(87):1-16. https://doi.org/10.54899/dcs.v23i87.4768. DOI: https://doi.org/10.54899/dcs.v23i87.4768
Rho NK, Bae GY, Choi MS, Chung WK, Kim HY, Kim HM, et al. Consensus on the cosmetic use of a novel botulinum neurotoxin type A product (NEWLUX®) for facial expression muscles: 2024 guidelines and discussions by Korean experts. Toxins (Basel). 2025;17(2):61. https://doi.org/10.3390/toxins17020061. DOI: https://doi.org/10.3390/toxins17020061
Myung Y, Woo K, Kim ST. Treatment of gummy smile using botulinum toxin: a review. J Dent Rehabil Appl Sci. 2021;37(2):61-72. https://doi.org/10.14368/jdras.2021.37.2.61. DOI: https://doi.org/10.14368/jdras.2021.37.2.61
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