Comparison of Initial Stress and Displacement On Vertically Displaced Canines Using Conventional Bracket System and Self-Ligating Bracket System – A Finite Element Study

Aim: This study aimed to assess and compare the initial stress and displacement in vertically displaced canines using finite element analysis. Both conventional and self-ligating bracket systems were evaluated at displacement heights of 2, 4, and 6 mm. Methods: Six finite element models of maxillary dentitions with canines vertically displaced by 2, 4, and 6 mm were developed using specialized software. Continuous archwire techniques were applied in both the conventional system with 0.022" × 0.028" slot MBT brackets (3M Unitek™) and the self-ligating system with 0.022" × 0.028" slot passive self-ligating brackets (DAMON Q by ORMCO), both utilizing a 0.014-inch CuNiTi archwire. The study calculated canine displacement, reactionary effects on adjacent teeth (lateral incisors and first premolars), and compressive and tensile stresses along the X, Y, and Z axes at 12 specific points. Results: The self-ligating bracket system demonstrated greater extrusion of the canine compared to the conventional bracket system, with the most significant movement observed in the 2-mm model, followed by the 4-mm and 6-mm models. Reactionary effects on adjacent teeth included intrusion and tipping away from the canine, most pronounced in the 2-mm model. Compressive and tensile stresses were higher in the conventional bracket system and decreased with increased displacement. Conclusion: For vertically displaced canines, using a continuous archwire with a self-ligating bracket system is more advantageous than a conventional bracket system, as it results in greater canine movement and less stress on adjacent teeth. However, its effectiveness diminishes with increased displacement height due to resistance caused by higher contact angles and decreased wire expression.