Schulz Scott O, McNamara James A, Baccetti Tiziano, Franchi Lorenzo
University of Michigan, Ann Arbor, 48109, USA.
Am J Orthod Dentofacial Orthop. 2005 Sep;128(3):326-36. doi: 10.1016/j.ajodo.2004.03.039.
The aim of this study was to investigate the effectiveness of vertical-pull chincup (VPCC) therapy during an initial rapid maxillary expansion (RME) phase, followed by a second phase of comprehensive orthodontic therapy in growing subjects with mild-to-severe hyperdivergent facial patterns.
The records of 29 subjects treated with bonded RME combined with VPCC followed by a fixed-appliance phase with continued use of VPCC were compared with a group of 29 well-matched patients treated with bonded RME only. Lateral cephalograms were analyzed before the start of treatment (T1), before the second phase of treatment (T2), and after the second phase of treatment (T3). Mean age at T1 was approximately 9 years for both groups. Total treatment period (phase 1, interim phase, and phase 2) was 5.7 years for the VPCC group and 6.2 years for the bonded RME-only group. Statistical comparison between the 2 groups was performed by means of independent sample t tests on the T2-T1, T3-T2, and T3-T1 changes. Cervical vertebral maturation stages were assessed at T1, T2, and T3.
The VPCC induced significantly smaller increases in mandibular plane angle of about 2 degrees , lower anterior facial height of about 2.5 mm, and total anterior facial height of about 3.5 mm, compared with the RME-only subjects. These outcomes reflect the therapeutic changes that occurred during phase 1 treatment; phase 2 treatment was not associated with any significant difference in treatment response. No statistically significant differences in vertical dentoalveolar changes were concurrent with the vertical skeletal changes in the subjects treated with the VPCC compared with the RME-only group.
The clinical significance of VPCC wear over 2 phases of treatment (5.7 years) appears to be limited. The VPCC was most effective during the initial (RME) phase of treatment and of little benefit during the fixed appliance phase.
本研究的目的是调查在生长发育期的轻至重度高角面型患者中，在初始快速上颌扩弓（RME）阶段采用垂直牵引颏兜（VPCC）治疗，随后进行第二阶段综合正畸治疗的有效性。
将29例接受粘结式RME联合VPCC治疗，随后进入固定矫治器阶段并继续使用VPCC的患者记录，与29例仅接受粘结式RME治疗的匹配良好的患者组进行比较。在治疗开始前（T1）、第二阶段治疗前（T2）和第二阶段治疗后（T3）分析头颅侧位片。两组在T1时的平均年龄约为9岁。VPCC组的总治疗期（第一阶段、过渡期和第二阶段）为5.7年，仅粘结式RME组为6.2年。通过对T2 - T1、T3 - T2和T3 - T1变化进行独立样本t检验，对两组进行统计学比较。在T1、T2和T3评估颈椎成熟阶段。
与仅接受RME治疗的受试者相比，VPCC导致下颌平面角增加明显更小，约2度，下前牙面部高度降低约2.5毫米，上前牙面部总高度降低约3.5毫米。这些结果反映了第一阶段治疗期间发生的治疗性变化；第二阶段治疗在治疗反应方面没有显著差异。与仅接受RME治疗的组相比，接受VPCC治疗的受试者的垂直牙牙槽变化与垂直骨骼变化没有统计学上的显著差异。
在两个治疗阶段（5.7年）佩戴VPCC的临床意义似乎有限。VPCC在治疗的初始（RME）阶段最有效，在固定矫治器阶段益处不大。
