Functional and esthetic effects of botulinum toxin injection into the masseter muscles: evaluation of 80 patients from a dermatological perspective

Abstract

Background: Masseter muscle hypertrophy is characterized by a symmetrical or asymmetrical increase in muscle volume. Although it can be asymptomatic, it may be associated with bruxism. Therefore, patients may seek intervention for esthetic and/or functional concerns. This study aimed to establish patient characteristics, purpose of undergoing botulinum toxin injection into the masseter muscles, efficacy, and side effects of the procedure at a dermatology clinic.

Methods: A retrospective chart review was carried out over a period of one year from January 2022 to January 2023 for the patients who underwent botulinum toxin injection into the masseter muscles. The general characteristics of patients, the purpose of botulinum toxin treatment, relief levels regarding bruxism according to the Visual Analog Scale (VAS), side effects, and complications were recorded.

Results: The study group comprised 74 female and 6 male patients with a mean age of 31.20 ± 6.71 years. Eighteen (22.5%) patients were treated only for narrowing the lower face contour, 28 (35%) patients were treated only for the relief of bruxism, and 34 (42.5%) patients were treated for both indications. Fifteen (18.8%) patients experienced 16 treatment-related side effects, including two (2.5%) with smile asymmetry and two (2.5%) with paradoxical bulging.

Conclusions: Botulinum toxin injection into the masseter muscles with the intention of lower face contouring and/or relieving bruxism offers a minimally invasive, safe, and effective treatment option. Although it has a favorable safety profile, the risks of significant side effects or complications remain.

Keywords: botulinum toxin; bruxism; lower face contour; masseter; masseter botox.