An experimental study of dynamic frictional resistance between orthodontic bracket and arch wire / 대한치과교정학회지

This investigation was designed to determine the effects of wire size, bracket width and the number of bracket on bracket-wire dynamic frictional resistance during simulating arch wire-guided tooth movement in vitro. For simulation of an arch wire-guided tooth movement, we simulated tooth, periodontal ligament and cancellous bone. Maxillary premolar and 1st molar were simulated as real sized resin teeth, the simulated resin teeth which its root was coated by polyether impression material which its elastic modulus is similar to periodontal ligament were embedded in steel housing with inlay wax which its elastic modulus is similar to cancellous bone. Stainless steel wires in four wire size (0.016, 0.018, 0.016 x 0.022, 0.019 x 0.025 inch) were examined with respect to three (stainless steel) bracket widths (2.4, 3.0, 4.3mm) and the number of medium bracket(one, two, three) included in the experimental assembly under dry condition. The wires were ligated into the brackets with elastomeric module. The results were as follows : 1. In all the brackets, frictional resistance increased with increase in wire size. But, statistically similar levels of frictional resistance were observed between 0.018 inch and 0.016 x 0.022 inch wires in narrow bracket and also between 0.016 inch and 0.018 inch wire in wide backet. 2. The frictional forces produced by 0.016 inch wire were statistically similar levels in all the brackets. In 0.018 inch round wire, wide bracket was associated with lower amounts of friction than both narrow and medium brackets. In 0.016 x 0.022, 0.019 x 0.025 inch rectangular wire, wide bracket produced larger friction than both narrow and medium brackets. In all the wires, narrow and medium bracket demonstrated no statistical difference in levels of frictional resistance. 3. Frictional resistance increased with increase in number of medium bracket. 0.016 inch round wire demonstrated the greatest increment in frictional resistance, followed by 0.019 x 0.025, 0.016 x 0.022 inch rectangular wire which were similar level in increment of frictional resistance, 0.018 inch wire demonstrated the least increment. The increments of frictional resistance were not constantly direct proportion to number of bracket.

An experimental study on dynamic frictional resistance between brackets and archwires under the wet condition / 实用口腔医学杂志

Objective:To study the dynamic frictional resistance in the buccal segment between preadjusted brackets coupled with different archwires,at different times under artificial saliva condition.Methods: The dynamic friction of different combinations of 4 kinds of preadjusted brackets and 4 archwires were tested simulating archwires sliding in the buccal segments at 4 different times(0,15,30,45 d)under artificial saliva condition by using Instron universal testing machine.Results: The dynamic frictional resistance of combinations of 3M MBT bracket and all archwires were the smallest.The combinations of 0.46 mm inch stainless steel round wire and all brackets produced significantly lower dynamic frictional resistance than that of other archwires.The 0.48 mm?0.64 mm inch stainless steel rectangular wire produced the highest dynamic frictional resistance combined with all preadjusted brackets.The dynamic frictional resistance of combinations of archwires and brackets were highest at the 15th day and smallest at the 30th day under artificial saliva condition.Conclusion: 0.46 mm stainless steel round wire produces the smallest dynamic frictional resistance combined with all preadjusted brackets.3M MBT brackets are more favorable to sliding mechanics compared with other brackets.As for time,the lowest dynamic frictional resistance exhibits at the 30th day under artificial saliva condition.