An innovative multilayered neurotoxin injection technique for the mentalis muscle: A comparative study with superficial and deep approaches
Keywords:
Botulinum toxin, Mentalis muscle, Multilayered injection, Aesthetic outcomes, Facial contourAbstract
Background: The mentalis muscle critically influences chin contour and lower facial aesthetics. Conventional botulinum toxin injections, targeting either superficial or deep layers, often produce variable results in muscle relaxation, skin smoothness, and facial harmony. A multilayered injection strategy may improve outcomes by addressing multiple muscle depths while preserving natural facial movement.
Objective: To compare the aesthetic outcomes and safety of superficial, deep, and multilayered botulinum toxin injection techniques in the mentalis muscle.
Methods: Thirty Middle Eastern female participants were allocated into three groups (n=10 each): superficial, deep, and multilayered injections. Muscle activity was assessed via electromyography, while aesthetic improvements were evaluated using standardized photographs and patient satisfaction scores. Adverse events were systematically recorded.
Results: The multilayered injection group demonstrated superior outcomes, including balanced chin contour, smoother skin texture, and higher patient satisfaction (p<0.05) compared to single-depth techniques. This approach minimized excessive relaxation and asymmetry, preserving natural lower facial dynamics. Minor transient effects were observed in other groups, but no major complications occurred.
Conclusion: Multilayered botulinum toxin injections in the mentalis muscle provide enhanced aesthetic outcomes with minimal complications, suggesting a refined and effective alternative to conventional single-depth techniques. Further studies with larger cohorts are warranted to validate these findings.
References
1. Choi DY, Bae H, Bae JH, Kim HJ, Hu KS. Effective locations for injecting botulinum toxin into the mentalis muscle: cadaveric and ultrasonographic study. Toxins (Basel). 2021;13(2):96. doi: 10.3390/toxins13020096
2. Yi KH, Kim HJ, Lee JH, Hu HW. Novel anatomical guidelines for botulinum neurotoxin injection in the mentalis muscle: a review. Anat Cell Biol. 2023;56(1):1–7. doi: 10.5115/acb.22.273
3. Polacek Plastic Surgery. Exploring the benefits of mentalis BOTOX injections [Internet]. 2025. Available from:
https://www.polacekplasticsurgery.com/exploring-the-benefits-of-mentalis-botox-injections/
4. Sökmen K, Yıldırım TT, Dündar S. Effect of botulinum toxin-A injection applied to the mentalis muscle on free gingival graft operation: A retrospective study. J Esthet Restor Dent. 2024;36(2):335–45. doi: 10.1111/jerd.13110
5. Yi KH, Lee JH, Hu HW, Choi YJ, Bae H, Kim HJ. Novel anatomical proposal for botulinum neurotoxin injection targeting depressor anguli oris for treating drooping mouth corner. Anat Cell Biol. 2023;56(2):161–5. doi: 10.5115/acb.22.272
6. Sirisuthivoranunt S, Wongdama S, Phumariyapong P, Nokdhes YN, Chaiyasit N, Chaiyasit W. Comparative study on the duration and efficacy of various botulinum toxin type A injections for reducing masseteric muscle bite force and treating facial wrinkles. Dermatol Ther (Heidelb). 2024;14(3):1315–25.
doi: 10.1007/s13555-024-00791-1
7. Hwang K, Kim DJ, Hwang SH. Surface anatomy of the mentalis muscle. J Craniofac Surg. 2023;24(1):362–4.
doi: 10.1097/SCS.0000000000008906
8. Gassia V, Raspaldo H, Niforos FR. Botulinum toxin A for the lower face: the importance of accurate anatomical landmarks. J Cosmet Laser Ther. 2023;7(1):31–9.
doi: 10.1080/14764172.2022.2152545
9. Kim NH, Chung JH, Park RH, Park JB. The use of botulinum toxin type A in aesthetic mandibular contouring. Plast Reconstr Surg. 2023;115(3):919–30. doi: 10.1097/01.PRS.0000193802.54816.2C
10. Yu N, Liu Y, Chen C, Dong R, Zhang Y, Zhang Y. Paradoxical bulging of mentalis after botulinum toxin type A injection. J Cosmet Dermatol. 2020;19(5):1290–3. doi: 10.1111/jocd.13247
11. Hur MS, Kim HJ, Choi BY, Hu KS, Kim YJ, Lee JH. Morphology of the mentalis muscle and its relationship with the orbicularis oris and incisivus labii inferioris muscles. J Craniofac Surg. 2013;24(2):602–4.
doi: 10.1097/SCS.0b013e31828f3e1d
12. Ramirez-Castaneda J, Jankovic J, Comella C, Dashtipour K, et al. Diffusion, spread, and migration of botulinum toxin. Mov Disord. 2013;28(14):1775–83. doi: 10.1002/mds.25636
13. Shaari CM, George E, Wu BL, Biller HF, et al. Quantifying the spread of botulinum toxin through muscle fascia. Laryngoscope. 1991;101(9):960–4. doi: 10.1288/00005537-199109000-00004
14. Tang K, Wu Y, Wu W, Zheng K, Zhang Y, Li Z. Ultrasound-guided "cross injection" technique for mouth corner lift with botulinum toxin type A. Aesthetic Plast Surg. 2024;48(2):347–54.
doi: 10.1007/s00266-023-01988-7
15. Munoz-Lora VRM, Thiesen V, Loureiro D, Giro G, et al. Understanding clinical meaningfulness when targeting the depressor anguli oris muscle (DAO) with neuromodulators: a clinical prospective interventional study. J Neural Transm (Vienna). 2024;131(1):1–9.
doi: 10.1007/s00702-023-02551-2
16. Battaglia M, Borg MB, Torgano L, Loro A, et al. The lack of systemic and subclinical side effects of botulinum neurotoxin type-A in patients affected by post-stroke spasticity: a longitudinal cohort study. Toxins (Basel). 2022;14(8):564.
doi: 10.3390/toxins14080564
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