Edition V16N01 | Year 2011 | Editorial Article | Pages 116 to 125
Objective: To evaluate the force system generated by T-springs placed in the center of the interbracket space using the pre-activations advocated by Burstone. Material and Methods: Photoelastic models were used to assess T-springs fabricated with 0017?x0.025? rectangular titanium-molybdenum alloy wire (TMA), centrally positioned, with 6.0 mm activation, 3 mm activation, and in neutral position. To ensure reliable results, tests were repeated on three photoelastic models equally duplicated and fabricated by the same operator. An interbracket distance of 27.0 mm was used. For a better understanding of the results, the fringes were viewed in a polariscope, then photographed and qualitatively analyzed. Results: Through qualitative analysis of the fringe order in the photoelastic model it was noted that both the retraction and anchorage ends displayed force system symmetry across the full extent of the root.