Bell R A, LeCompte E J
Am J Orthod. 1981 Feb;79(2):152-61. doi: 10.1016/0002-9416(81)90313-4.
Ten subjects, five in the deciduous dentition and five in the mixed dentition (mean age = 6 years 9 months), had functional posterior cross-bites successfully corrected with fixed lingual arch wire expansion appliances of the quad-helix design. The appliance, in the context of "early" treatment, produced midpalatal suture separation on each subject as evidenced on occlusal radiographs. While the relative orthopedic and orthodontic changes were not determined, the maxillary intermolar and intercanine transverse measurements showed significant increases in all subjects, with mean values of +5.3 mm. and +4.1 mm., respectively. The active phase of treatment averaged 30 days and 1.1 adjustments for the desired expansion to be achieved. Incorporating a standard 6-week retention period, the total appliance wear time had a mean value of 75 days. Following a 3-month postretention adjustment period, relapse of the intermolar and intercanine transverse dimensions presented mean decreases of -1.5 mm. and -1.9 mm., respectively. The relapse potential was successfully compensated for by overexpansion of 2 to 3 mm. during the active phase of treatment. No significant differences were demonstrated between the deciduous- and mixed-dentition groups during the course of maxillary expansion with the quad-helix appliance.
十名受试者，五名处于乳牙列期，五名处于混合牙列期（平均年龄6岁9个月），使用四螺旋设计的固定舌弓丝扩弓矫治器成功矫治了功能性后牙反合。在“早期”治疗的背景下，该矫治器使每个受试者的腭中缝分离，这在咬合X线片上得到了证实。虽然未确定相对的矫形和正畸变化，但所有受试者的上颌磨牙间和尖牙间横向测量值均显著增加，平均值分别为+5.3毫米和+4.1毫米。治疗的活跃期平均为30天，为实现预期的扩弓平均进行1.1次调整。纳入标准的6周保持期后，矫治器的总佩戴时间平均值为75天。在3个月的保持后调整期后，磨牙间和尖牙间横向尺寸的复发分别呈现出平均-1.5毫米和-1.9毫米的减小。在治疗的活跃期通过2至3毫米的过度扩弓成功补偿了复发潜力。在使用四螺旋矫治器进行上颌扩弓的过程中，乳牙列组和混合牙列组之间未显示出显著差异。
