Baccetti Tiziano, Franchi Lorenzo, Schulz Scott O, McNamara James A
Department of Orthodontics, University of Florence, Florence, Italy.
Am J Orthod Dentofacial Orthop. 2008 Jan;133(1):58-64. doi: 10.1016/j.ajodo.2006.01.048.
The aim of this study was to investigate the role of treatment timing on the effectiveness of vertical-pull chincup (V-PCC) therapy in conjunction with a bonded rapid maxillary expander (RME) in growing subjects with mild-to-severe hyperdivergent facial patterns.
The records of 39 subjects treated with a bonded RME combined with a V-PCC were compared with 29 untreated subjects with similar vertical skeletal disharmonies. Lateral cephalograms were analyzed before (T1) and after treatment or observation (T2). Both the treated and the untreated samples were divided into prepubertal and pubertal groups on the basis of cervical vertebral maturation (prepubertal treated group, 21 subjects; pubertal treated group, 18 subjects; prepubertal control group, 15 subjects; pubertal control group, 14 subjects). Mean change differences from T2 to T1 were compared in the 2 prepubertal and the 2 pubertal groups with independent-sample t tests.
No statistically significant differences between the 2 prepubertal groups were found for any cephalometric skeletal measures from T1 to T2. When compared with the untreated pubertal sample, the group treated with the RME and V-PCC at puberty showed a statistically significant reduction in the inclination of the mandibular plane to the Frankfort horizontal (-2.2 mm), a statistically significant reduction in the inclination of the condylar axis to the mandibular plane (-2.2 degrees), and statistically significant supplementary growth of the mandibular ramus (1.7 mm).
Treatment of increased vertical dimension with the RME and V-PCC protocol appears to produce better results during the pubertal growth spurt than before puberty, although the absolute amount of correction in the vertical skeletal parameters is limited.
本研究的目的是调查治疗时机对垂直牵引颏兜（V-PCC）疗法联合粘结式快速上颌扩弓器（RME）治疗轻度至重度高角面型生长发育期患者疗效的影响。
将39例接受粘结式RME联合V-PCC治疗的患者记录与29例具有相似垂直骨骼不协调的未治疗患者记录进行比较。在治疗前（T1）以及治疗或观察后（T2）分析头颅侧位片。根据颈椎成熟度将治疗组和未治疗组均分为青春期前组和青春期组（青春期前治疗组，21例患者；青春期治疗组，18例患者；青春期前对照组，15例患者；青春期对照组，14例患者）。采用独立样本t检验比较两个青春期前组和两个青春期组从T2到T1的平均变化差异。
从T1到T2，两个青春期前组在任何头影测量骨骼指标上均未发现统计学显著差异。与未治疗的青春期样本相比，青春期接受RME和V-PCC治疗的组在下颌平面相对于Frankfort平面的倾斜度上有统计学显著降低（-2.2mm），髁突轴相对于下颌平面的倾斜度有统计学显著降低（-2.2°），下颌升支有统计学显著的额外生长（1.7mm）。
尽管垂直骨骼参数的绝对矫正量有限，但采用RME和V-PCC方案治疗垂直维度增加在青春期生长突增期似乎比青春期前能产生更好的效果。
