Abstract
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, $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$ 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 $0.016\;{\times}\;0.022$ 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 $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$ inch rectangular wire, wide bracket produced target friction than both narrow and medium brackets. In all the wirer, 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 $0.019\;{\times}\;0.025,\;0.016\;{\times}\;0.022$ 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.
이 연구의 목적은 호선으로 유도되는 치아이동을 실험실에서 실험하는 동안 브라켓과 선재의 운동 마찰저항에 대한 브라켓 수, 브라켓 폭경, 선재 크기가 미치는 영향을 관찰하기 위한 것이다. 상악 제 1, 2소구치, 제 1대구치와 유사한 크기의 레진 치아를 사용하였으며, 치주인대와 탄성계수가 비슷한 폴리 에테르 인상재를 사용하였다. 스테인레스 스틸 트윈 에지와이즈 브라켓으로 좁은 폭경 (2.4 mm), 중간 폭경 (3.0 mm), 넓은 폭경 (4.3 mm)을 사용하였으며, 강선으로는 0.016, 0.018, $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$인치의 굵기를 사용하였고, 결찰은 합성고무링을 이용하고, 제1소구치에 부착된 좁은 폭경 브라켓 1개, 제 1, 2소구치에 부착된 2개의 중간 폭경 브라켓 및 제 1, 2소구치와 제 1대구치에 부착된 3개의 중간 폭경 브라켓과 각 강선 사이의 운동 마찰저항력을 계측하여 다음의 결론을 얻었다. 1. 좁은 폭경, 중간 폭경, 넓은 폭경 세 종류의 브라켓 모두에서 교정용 선재의 단면 크기가 증가할수록 마찰저항력도 증가하였다. 2. 0.016, 0.018인치 원형 강선은 브라켓 폭경이 증가하면 운동마찰저항력은 감소하며, $0.016\;{\times}\;0.022,\;0.019\;{\times}\;0.025$인치 각형 강선은 브라켓 폭경이 증가하면 운동마찰저항력이 증가하는 경향이 있었고0.016인치 원형 강선과 폭경이 다른 브라켓과의 운동마찰저항력 사이에는 통계적으로 유의차가 없었다. 3. 중간 폭경 브라켓의 수가 증가할수록 마찰저항력은 크게 나타났으며, 그 증가율은 브라켓의 수에 비례하였으나 정수배로 증가하지는 않았고 강선의 굵기에 따라 차이가 있었다.