Comparative Study on the Duration and Efficacy of Various Botulinum Toxin Type A Injections for Reducing Masseteric Muscle Bite Force and Treating Facial Wrinkles.

[OBJECTIVE] Botulinum toxin serotype A (BoNT/A) is widely used for minimal invasive aesthetic treatments. Different brands of BoNT/A exhibit structural variations. The aim of this study was to compare the duration and efficacy of various BoNT/A brands available in Thailand for reducing bite force and treating wrinkles.

[METHODS] Fifty participants were randomly assigned to one of five groups, with each group receiving a different BoNT/A brand, namely, incobotulinumtoxinA (IncoA), onabotulinumtoxinA (OnaA), abobotulinumtoxinA (AboA), letibotulinumtoxinA (LetiA), and prabotulinumtoxinA (PraboA). BoNT/A was administered to the masseter muscle and the upper face. Bite force was measured before injection and at 2, 4, 8, 12, 16, 20, and 24 weeks post-injection. Evaluation scores for wrinkle improvement were assessed after the treatment.

[RESULTS] The most significant reduction in bite force occurred between 2 and 4 weeks post-injection. PraboA demonstrated the most substantial reduction in bite force, while IncoA had the least effect. However, the percentage of bite force reduction did not exhibit statistical significance between BoNT/A types. Additionally, the reduction in bite force for all BoNT/A types was reversed at 4 months post-injection. More than half of the participants experienced improvement beyond 16 weeks.

[CONCLUSIONS] The structural differences among BoNT/A brands did not significantly affect the longevity and efficacy of bite force reduction and wrinkle treatment.

[TRIAL REGISTRATION] ClinicalTrials.gov identifier: TCTR20211205001 (registered 4 Dec 2021).