Meling T R, Odegaard J
Department of Maxillofacial Surgery, Ullevaal Hospital, Oslo, Norway.
Angle Orthod. 1998 Aug;68(4):369-76. doi: 10.1043/0003-3219(1998)068<0369:TEOSTT>2.3.CO;2.
Due to their exceptional temperature sensitivity, superelastic nickel titanium wires may be affected by temperature changes associated with ingestion of cold or hot food. It has been assumed that the alterations in archwire stiffness associated with short-term cooling or heating are transient. This investigation studied the effect of these temperature changes on the torsional stiffness of nickel titanium alloys. Eight rectangular superelastic wires were activated to 20 degrees, in longitudinal torsion at body temperature and subjected to cold (10 degrees C) or hot (80 degrees C) water with the strain held constant. The torsional stiffness of some wires was strongly affected. The effect of hot water disappeared quickly, but the wires remained at a level of reduced torsional stiffness (up to 85% less than baseline) after short applications of cold water. The most thermodynamic archwires showed incremental reductions in torsional stiffness when cold water was repeatedly applied. Furthermore, the torsional stiffness remained low (up to 50% less than baseline) and showed no tendency to increase even after 2 hours of post-exposure restitution. It is conceivable that some wires may provide inadequate forces for tooth movement after ingestion of cold liquids.
由于其极高的温度敏感性，超弹性镍钛丝可能会受到与摄入冷或热食物相关的温度变化的影响。据推测，与短期冷却或加热相关的弓丝刚度变化是短暂的。本研究探讨了这些温度变化对镍钛合金扭转刚度的影响。八根矩形超弹性丝在体温下纵向扭转激活至20度，并在应变保持恒定的情况下置于冷水（10摄氏度）或热水（80摄氏度）中。一些丝的扭转刚度受到强烈影响。热水的影响很快消失，但在短时间接触冷水后，丝的扭转刚度仍保持在降低水平（比基线低85%）。当反复施加冷水时，最具热动力学特性的弓丝扭转刚度逐渐降低。此外，即使在暴露后恢复2小时后，扭转刚度仍保持较低水平（比基线低50%），且没有增加的趋势。可以想象，摄入冷液体后，一些丝可能无法为牙齿移动提供足够的力量。
