[Biomechanical justification of third order bends application by using edgewise technique].

Aim of this study is to give theoretical substantiation of magnitude of arch wire diameter decrease in area of adjacent teeth for reducing undesirable reciprocal deflections by redistribution of the force on more teeth during making torsion bends on rectangular orthodontic arch wires for correction of vestibulolingual position of individual teeth. By means of mathematical analysis, was determined relationship between the angle of tooth inclination and the radius of orthodontic arch wire overcast, which will allow managing moments that affect adjacent teeth.

[Characterizing of parameters of shape memory and elasticity of nickel-titanium wires by electro thermal influence].

Optimal parameters of electro thermal influence on nickel-titanium wires for giving them new shape (bends) without losing basic physical properties - shape memory, elasticity are determined in terms of clinic. It is confirmed that by thermal influence of electric current on nickel-titanium wires it's possible to achieve new shape without changing the parameters of elasticity. Optimal parameters of continuous current intensity (strength) and interaction time are determined for: Nitinol 0.016, 0.016 x 0.022, NeoSentalloy 0.016 x 0.022 (GAC International, Inc). It was established that during heat treatment of nickel-titanium arch wires the shape of wire changes earlier than the elasticity.