Angle Orthod. 2018 Jan;88(1):20-26. doi: 10.2319/06417-424R. Epub 2017 Oct 6.
To analyze and compare external apical root resorption (EARR) of maxillary incisors treated by intrusion arch or continuous archwire mechanics.
This cone-beam computed tomography (CBCT) study analyzed 28 deep bite patients in the permanent dentition who were randomly divided into two groups: Group 1, 12 patients with initial mean age of 15.1 ± 1.6 years and mean overbite of 4.6 ± 1.2 mm treated with the Connecticut intrusion arch (CIA) in the upper arch (Ortho Organizers, Carlsbad, Calif) for a mean period of 5.8 ± 1.27 months. Group 2, 16 patients with initial mean age of 22.1 ± 5.7 years and mean overbite of 4.1 ± 1.1 mm treated with conventional leveling and alignment using continuous archwire mechanics for 6.1 ± 0.81 months. The degree of EARR was detected in 112 maxillary incisors by using CBCT scans and a three-dimensional program (Dolphin 11.7, Dolphin Imaging & Management Solutions, Chatsworth, Calif). The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were assessed by nonpaired and paired t-tests, respectively, with a 5% significance level.
Significant differences were found for both groups between T1 and T2 ( P < .05) indicating that EARR occurred in both groups. However, there were no significant differences when EARR was compared between group 1 (-0.76 mm) and group 2 (-0.59 mm).
The Connecticut intrusion arch did not lead to greater EARR of maxillary incisors when compared with conventional orthodontic mechanics.
分析和比较上颌切牙采用压入弓或连续弓丝力学治疗后的根尖外向吸收（EARR）。
本锥形束 CT（CBCT）研究分析了 28 名恒牙深覆患者，这些患者随机分为两组：第 1 组 12 例，初始平均年龄为 15.1 ± 1.6 岁，平均覆合为 4.6 ± 1.2mm，采用康涅狄格州压入弓（CIA）（Ortho Organizers，Carlsbad， Calif）在上颌弓中治疗，平均治疗时间为 5.8 ± 1.27 个月。第 2 组 16 例，初始平均年龄为 22.1 ± 5.7 岁，平均覆合为 4.1 ± 1.1mm，采用连续弓丝力学常规排齐整平，治疗时间为 6.1 ± 0.81 个月。使用 CBCT 扫描和三维程序（Dolphin 11.7，Dolphin Imaging & Management Solutions，Chatsworth，Calif）在 112 颗上颌切牙中检测 EARR 程度。在治疗开始前（T1）和 6 个月后（T2）获得 CBCT 扫描。分别采用非配对和配对 t 检验评估组间和组内差异，以 5%的显著性水平。
两组在 T1 和 T2 之间均有显著差异（P<0.05），表明两组均发生 EARR。然而，第 1 组（-0.76mm）和第 2 组（-0.59mm）之间的 EARR 无显著差异。
与传统正畸力学相比，康涅狄格州压入弓不会导致上颌切牙发生更大的 EARR。
