Preventive, Cumulative Effects of Botulinum Toxin Type A in Facial Aesthetics.

[BACKGROUND] Botulinum toxin Type A (BoNTA) is the gold standard for the treatment of dynamic rhytides in the face. Recently, clinical observation suggests that individuals who receive regular injections of BoNTA experience ongoing wrinkle reduction and improvements in overall skin quality not observed in those treated sporadically.

[OBJECTIVE] To review scientific evidence of qualitative changes in the skin and the possibility of indirect or direct effects on fibroblasts affecting fibroblast activity, including collagen production, after repeated treatment with BoNTA.

[MATERIALS AND METHODS] We examined the literature for supporting evidence of the effect of repeated treatment cycles on wrinkle reduction and skin quality; histological changes in collagen structure; alterations in biomechanical features of the skin; and potential fibroblastic response.

[RESULTS] Apparent cumulative improvement on wrinkle reduction and additional skin quality attributes with regular BoNTA treatments suggests an ongoing process of dermal repair. Clinical observation suggests that BoNTA injections stimulate collagen production and lead to a reorganization of the collagen network within the extracellular matrix, which in turn may produce improvements in features associated with more youthful skin. Moreover, evidence suggests that BoNTA may have a direct or indirect effect on fibroblast activity.

[CONCLUSION] Clinical observation of progressive wrinkle reduction and qualitative improvements in a number of skin attributes that accumulate with more frequent injections of BoNTA suggest an ongoing process of repair leading to prolonged and cumulative effects.