方丝弓技术平行近移第二磨牙的临床研究

A Clinical Study of the Second Molar Transition Mesially by Edgewise Technique

目的 研究第一磨牙拔除后用方丝弓技术近中平移上下颌第二磨牙的临床效果。方法 选择15例,计24颗第二磨牙。使用0.017”×0.025”的不锈钢方丝,弯制T形曲并设计末端20°的后倾弯,应用180 g的力值,使第二磨牙近中平行到达第一磨牙的位置。每4周取模测量磨牙近移的距离。结果 上颌第二磨牙平均近移(9.66±1.12)mm,平均近移的时间为(6.84±0.86)个月,近移的速率(1.44±0.22)mm/月;下颌第二磨牙平均近移(10.30±1.15)mm,平均近移时间为(7.52±0.98)个月,近移的速率为(1.35±0.18)mm/月。儿童比成人牙齿移动快,上颌磨牙移动快于下颌磨牙。结论 方丝弓弯制T形曲和末端20°后倾弯,加上温和持久的力值可以达到临床平移的效果。

Objective To study the second molar transition mesially with Edgewise technique. Methods 15 cases, including upper and lower 24 second molars, were chosen for this study. After the leveling of dentition, we used stainless retangular 0.017' × 0.025'wire, bending T loop and 20πwith tip back bent, making a gentle and continuous 180g force. The second molars had smoothly been moved to the position of the first molars. We made impressions and measured the distances of tooth moving per 4 weeks. Results Upper and lower second molars were mesially moved (9.66± 1.12)mm, and (10.20± 1.15)mm on average; upper and lower average durations for tooth moving were (6.84± 0.86) Mon and ( 7.52 ± 0.98 ) Mon. The rates of movement for upper and lower teeth were (1.44 ± 0.22 ) mm/month and (1.35± 0.18 ) mm/ month, respectively. The distance of tooth moving for children was longer than adults' and the distance of the upper teeth was longer than the lower s. Conclusion This clinical study indicated that it was satisfactory for the second molar transition mesially by means of square wire and bending T loop with 20?tip back bent and using suitable forces.