The invention relates to medicine, namely to dentistry and is intended to reinforce composite materials used for elimination various defects of hard dental tissues of carious and non-carious origin in the process of direct/indirect, reinforced/unreinforced composite restoration. The claimed method includes vibrational mechanical activation of composite materials by a vibrational impact on portions of composite material shaped by manual mechanical activation (e.g., roll/ball) and applied layer by layer to a defect area. A device for vibrational mechanical activation of a composite material includes at least one working part for applying a composite material to a defect, the working part fixedly attached to a handle, which is connected by a framework to a micromotor that creates vibration which are transferred via the working portion to a layer of composite material by distributing the same across the entire surface of the defect and achieving the simultaneous surface plastic deformation thereof.