Department of Orthodontics and Dentofacial Orthopedics, University of Missouri-Kansas City, Kansas City, MO, USA.
Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.
Orthod Craniofac Res. 2017 Jun;20 Suppl 1:63-67. doi: 10.1111/ocr.12161.
To test that the speed of tooth translation is not affected by stress magnitude and growth status.
Advanced Education Orthodontic clinics at the Universities of Nebraska Medical Center and Missouri-Kansas City. Forty-six consenting subjects with orthodontic treatment plans involving maxillary first premolar extractions.
This randomized split-mouth study used segmental mechanics with definitive posterior anchorage and individual vertical-loop maxillary canine retraction appliances and measured three-dimensional tooth movements. Height and cephalometric superimposition changes determined growing (G) and non-growing (NG) subjects. Subjects were appointed for 9-11 visits over 84 days for maxillary dental impressions to measure three-dimensional tooth movement and to ensure retraction forces were continuously applied via calibrated nitinol coil springs. Springs were custom selected to apply two different stresses of 4, 13, 26, 52 or 78 kPa to maxillary canines in each subject. Statistical analyses (α=0.050) included ANOVA, effect size (partial η ) and Tukey's Honest Significant Difference (HSD) and two-group t tests.
Distolateral translation speeds were 0.034±0.015, 0.047±0.019, 0.066±0.025, 0.068±0.016 and 0.079±0.030 mm/d for 4, 13, 26, 52 and 78 kPa, respectively. Stress significantly affected speed and partial η =0.376. Overall, more distopalatal rotation was shown by teeth moved by 78 kPa (18.03±9.50º) compared to other stresses (3.86±6.83º), and speeds were significantly higher (P=.001) in G (0.062±0.026 mm/d) than NG subjects (0.041±0.019 mm/d).
Stress magnitude and growth status significantly affected the speed of tooth translation. Optimal applied stresses were 26-52 kPa, and overall speeds were 1.5-fold faster in G compared to NG subjects.
测试牙移动速度是否受应力大小和生长状态的影响。
内布拉斯加大学医学中心和密苏里堪萨斯城大学的高级教育正畸诊所。46 名同意参与上颌第一前磨牙拔牙正畸治疗计划的患者。
这项随机分组的分口研究使用节段性力学，采用确定的后向锚定和个体化垂直环上颌尖牙牵引装置，并测量三维牙齿运动。身高和头影测量叠加变化确定生长（G）和非生长（NG）受试者。受试者在 84 天内进行 9-11 次就诊，进行上颌牙印模测量三维牙齿运动，并确保通过校准的镍钛诺线圈弹簧持续施加牵引力。根据每个受试者的情况，选择定制的螺旋弹簧施加 4、13、26、52 或 78kPa 的两种不同的力。统计分析（α=0.050）包括方差分析、效应大小（偏η）和 Tukey 的诚实显著差异（HSD）和两组 t 检验。
远中向的平移速度分别为 4kPa 时为 0.034±0.015mm/d、13kPa 时为 0.047±0.019mm/d、26kPa 时为 0.066±0.025mm/d、52kPa 时为 0.068±0.016mm/d、78kPa 时为 0.079±0.030mm/d。应力显著影响速度，偏η=0.376。总体而言，78kPa 移动的牙齿显示出更多的远中腭向旋转（18.03±9.50°），而其他应力下的旋转（3.86±6.83°），速度也显著更高（P=.001），G 组（0.062±0.026mm/d）比 NG 组（0.041±0.019mm/d）快 1.5 倍。
应力大小和生长状态显著影响牙齿移动的速度。最佳应用应力为 26-52kPa，与 NG 组相比，G 组的总体速度快 1.5 倍。
