M Dalstra1, B Melsen. 1. Department of Orthodontics, Royal Dental College, Aarhus University, Denmark. orthodpt@aau.dk
Abstract
OBJECTIVES: To describe the force systems developed by cantilevers with different configurations during incisor intrusion. DESIGN: A two-dimensional Finite Element model. SETTING AND SAMPLE STUDIED: Laboratories of the Department of Orthodontics, Royal Dental College, Aarhus University, Denmark. The materials studied comprised cantilevers made of 0.017" x 0.025" TMA wire. EXPERIMENTAL VARIABLE: Vertical activation of the six different modelled cantilever configurations. OUTCOME MEASURE: Force level and direction during activation and deactivation analysed at the point of force application. RESULTS: The force direction was dependent on the configuration of the cantilever. Only the cantilevers with a curvature produced combined retraction and intrusion forces. All other configurations resulted in combined protrusion and intrusion, which reversed into retraction and intrusion, according to the variations in deactivation. CONCLUSION: The choice of correct cantilever configuration is important when selecting the mechanics of intrusion for a particular patient.
OBJECTIVES: To describe the force systems developed by cantilevers with different configurations during incisor intrusion. DESIGN: A two-dimensional Finite Element model. SETTING AND SAMPLE STUDIED: Laboratories of the Department of Orthodontics, Royal Dental College, Aarhus University, Denmark. The materials studied comprised cantilevers made of 0.017" x 0.025" TMA wire. EXPERIMENTAL VARIABLE: Vertical activation of the six different modelled cantilever configurations. OUTCOME MEASURE: Force level and direction during activation and deactivation analysed at the point of force application. RESULTS: The force direction was dependent on the configuration of the cantilever. Only the cantilevers with a curvature produced combined retraction and intrusion forces. All other configurations resulted in combined protrusion and intrusion, which reversed into retraction and intrusion, according to the variations in deactivation. CONCLUSION: The choice of correct cantilever configuration is important when selecting the mechanics of intrusion for a particular patient.