Introduction. A search continues for effective means which may reduce the overload of harmful factors, eliminate the inflammatory process, and reduce stress on the periodontal tissues during the active period of orthodontic treatment. We developed and patented the gel composition (GC) Benzidaflaziverdine prepared based on Proteflazid® (flavonoids) and benzydamine hydrochloride (BH) T-Sept® for the local treatment of the periodontal tissues in the form of a periodontal dressing in the orthodontic patients. 
The aim of this study was to evaluate the cytocompatibility of different combinations of components in gel composition based on flavonoid complex and benzydamine hydrochloride (Benzidaflaziverdine) used for the treatment of periodontal diseases in orthodontic patients. For this, mechanisms of their cytopathic and cytoprotective effects will be explored using cultured human and mouse cells. 
Methods. We studied the effect of different supplements used in GC Benzidaflaziverdine on the viability of pseudonormal human keratinocytes of the HaCaT line and mouse fibroblasts of the BALB-3T3 line, and mouse macrophages of the J774.2 line. Various methods of cell survival assessment were used: MTT-assay, staining of cells with fluorescent dyes Hoechst 33342 and Propidium iodide (PI), as well as a test for the genotoxic effects on cells (DNA 
comet assay). The antioxidant properties of the developed GC variants were evaluated using DPPH (1,1-diphenyl-2-picrylhydrazyl), Merck (Dam-stadt, Germany), and DCFDA-H2 (2’,7’-dichlorodihydrofluorescein diacetate). 
Results. We demonstrated that the Sample containing gel base and BH in the form of a solution (Tantum Verde®) possessed weak prooxidant properties. While the Sample contained gel base, powdered BH (T-Sept®) and Sample containing gel base and powdered BH (T-Sept® and Proteflazid®) possessed pronounced antioxidant properties. 
Conclusions. Tests with DPPH and DCFDA dyes were used to confirm the hypothesis regarding the cytoprotective effect of the patented gel composition Benzidaflaziverdine for local application in the form of a periodontal bandage due to the antioxidant activity of the flavonoid complex, which reaches the maximum level at the 2nd hour of exposure. This gel composition can be recommended for use in clinical periodontology for medical support of  orthodontic patients before and during the active phase of orthodontic treatment.
Keywords: Flavonoid complex, Proteflazid®, benzydamine hydrochloride, gel composition, antioxidant activity, cell culture, periodontal diseases, orthodontic patients.