Comparison of frictional force between newly developed self-locking brackets and conventional tie-wing brackets / 中国组织工程研究

ABSTRACT

BACKGROUND: Imported self-locking brackets cost much. So it is necessary to develop low-cost and easy-to-operate domestic self-locking brackets.OBJECTIVE: To introduce a newly developed self-locking brackets, and investigate the frictional forces of the brackets. DESIGN, TIME AND SETTING: Biomechanical controlled analysis was performed in the Laboratory of Harbin Medical University in January 2004. MATERIALS: Self-made self-locking brackets and domestic conventional tie-wing stainless steel brackets; domestic Ni-Ti round wire, Australian stainless steel round wire, and domestic stainless steel rectangular wire. METHODS: Two kinds of brackets were combined with three kinds of arch wires. Under the drive of micromotor, pull sensor moved at 1 mm/min. An arch wire, which was ligated in the bracket, was dragged. Thus, teeth's shift was imitated.MAIN OUTCOME MEASURES: Waveshape was observed through the use of storage oscillograph and corresponding data were recorded. Frictional force was determined and compared.RESULTS: Under the same other conditions, no matter which kind of arch wires were combined with, tie-wing brackets produced greater frictional force than self-locking brackets (P < 0.001). Under the same other conditions, no matter which kind of brackets were combined with, Ni-Ti wire produced greater frictional force than Australian stainless steel round wire and domestic stainless steel rectangular wire (P < 0.001). In addition, domestic stainless steel rectangular wires produced greater frictional force than Australian stainless steel round wires (P < 0.001). CONCLUSION: Self-locking bracket produces low frictional force, so it is fit for orthodontic doctors to use the corrective force.