| Keywords [eng] |
Botulinum toxin type A, facial aesthetics, therapeutic indications, dynamic rhytids, blepharospasm, temporomandibular disorders, bruxism, complications. |
| Abstract [eng] |
Background: Botulinum toxin type A is a neurotoxic protein produced by Clostridium botulinum that has become one of the most widely used minimally invasive agents in both aesthetic and therapeutic facial medicine. Its clinical effect is based on presynaptic blockade of acetylcholine release at the neuromuscular junction through disruption of vesicle fusion proteins, producing reversible chemodenervation and temporary muscle relaxation. Aim: The aim of this thesis is to review the mechanism of action of botulinum toxin type A, describe the facial anatomy relevant to both aesthetic and therapeutic injection planning, summarize the main aesthetic and therapeutic indications, evaluate reported clinical outcomes, and discuss complications and adverse effects associated with facial botulinum toxin type A injections. Methods: A narrative literature review was conducted using biomedical databases, including PubMed/MEDLINE, Scopus, and Web of Science. Sources published between 2000 and 2025 were included, prioritizing peer-reviewed reviews, consensus recommendations, randomized controlled trials, and systematic reviews addressing the mechanism of action, indications, clinical effectiveness, and safety. Results: In aesthetic applications, the best-established indications are in the upper third of the face, particularly glabellar lines, lateral canthal lines, and horizontal forehead lines, demonstrating clinically meaningful wrinkle reduction and high patient satisfaction. Beyond the upper face, botulinum toxin type A is increasingly applied for midface and lower-face indications, including gummy smile correction, masseter hypertrophy, downturned oral commissures, platysmal bands, and chin texture irregularities, though the evidence base for these indications is comparatively less robust and requires more individualized patient assessment. In therapeutic applications, botulinum toxin type A represents the first-line treatment for blepharospasm and hemifacial spasm, and plays an established role in the management of facial synkinesis following peripheral facial nerve injury. Its therapeutic utility further extends to orofacial pain management, where intramuscular injections targeting the masticatory musculature provide clinically meaningful relief in patients with bruxism and temporomandibular disorders through both neuromuscular blockade and direct modulation of nociceptive signaling. Clinical outcomes across all indications demonstrate a generally favorable safety profile, with most adverse events being mild and transient. Technique-dependent complications, including eyelid ptosis, brow asymmetry, diplopia, and functional imbalance in the lower face, underscore the importance of precise anatomical knowledge, individualized dosing, and careful patient selection. 5 Conclusion: In conclusion, the successful clinical use of botulinum toxin type A in the facial region depends on an integrated understanding of its pharmacological mechanism, relevant facial anatomy, and the specific requirements of each indication — whether aesthetic or therapeutic. Further high-quality comparative studies are needed, particularly for less standardized indications in the lower face, neck, and orofacial pain management. |
