Botulinum toxin a for lower facial contouring: a prospective study

Area of Science:

• Aesthetic medicine
• Facial rejuvenation
• Neuromodulation

Background:

• Prominent mandibular angles are a common aesthetic concern for Asian women.
• Hypertrophic masseteric muscles often contribute to a prominent mandibular angle.
• Botulinum toxin A (BoNTA) is utilized for masseter hypertrophy treatment, but its detailed effectiveness and physiological effects require further investigation.

Purpose of the Study:

• To evaluate the effectiveness and physiological influences of botulinum toxin A (BoNTA) injections for treating hypertrophic masseteric muscles in Asian women.
• To assess facial changes, patient-reported outcomes, and muscle volume alterations following BoNTA treatment.

Main Methods:

• A prospective study involving 10 female volunteers with hypertrophic masseteric muscles.
• Single intramuscular injection of BoNTA.
• Assessment of facial changes and injection discomfort via visual analog scale.
• Regular patient inspection for up to 1 year.
• Measurement of bite forces and 3D CT scans for muscle volume evaluation before and 3 months post-injection.

Main Results:

• Significant facial contour changes observed 3-6 months post-injection.
• A mean 30% reduction in masseter muscle volume confirmed by 3D CT scans.
• Temporary decrease in bite force, recovering within 3 months without functional interference.
• No serious complications reported during the study period.

Conclusions:

• BoNTA injections provide an effective method for lower facial contouring by reducing masseter muscle bulk.
• Peak effectiveness for facial contouring is achieved around 3 months post-injection.
• The observed reduction in masseteric muscle volume and associated facial changes are temporary, with gradual return to baseline around 6 months.