Defraia Efisio, Marinelli Andrea, Baroni Giulia, Tollaro Isabella
Department of Orthodontics, University of Florence, Italy.
Prog Orthod. 2007;8(2):260-7.
The aim of this article was to analyze the changes in the transverse dimensions of the dental arches produced by a removable expansion plate (Removable Spring Expander, RSE) in subjects with unilateral posterior crossbite.
The treated group (TG) comprised of 17 subjects (5 males and 12 female) with unilateral posterior crossbites. Dental casts were available at pre-treatment (T1) and at a post-retention observation period (T2). The mean age at T1 was 6 years +/- 1 year and 4 months, and 7 years 11 months +/- 1 year and 5 months at T2. Seventeen subjects (7 males, 10 females) with an untreated unilateral posterior crossbite were used as the control group (CG). The mean age was 5 years 11 months +/- 1 year and 2 months at T1 and 7 years 9 months +/- 1 year and 4 months at T2. Post-retention changes in the transverse dimensions of the dental arches were evaluated statistically by means of a t-test for independent samples.
The TG showed statistically significant increments when compared with untreated controls in maxillary intermolar widths (4.5 mm), intercanine widths (3.6 mm), and there were significant improvements in the posterior transverse interarch discrepancy (4.2 mm) and in the anterior transverse interarch discrepancy (3.3 mm). No statistically significant differences were found for the mandibular intermolar and intercanine widths between TG and CG.
The expansion plate is a simple and effective device for the expansion of the upper arch in the deciduous and early mixed dentitions.
本文旨在分析可摘式扩弓板（可摘弹簧扩弓器，RSE）对单侧后牙反合患者牙弓横向尺寸的改变。
治疗组（TG）由17例单侧后牙反合患者组成（5例男性，12例女性）。在治疗前（T1）和保持后观察期（T2）均获取了石膏模型。T1时的平均年龄为6岁±1岁4个月，T2时为7岁11个月±1岁5个月。17例未经治疗的单侧后牙反合患者（7例男性，10例女性）作为对照组（CG）。T1时的平均年龄为5岁11个月±1岁2个月，T2时为7岁9个月±1岁4个月。通过独立样本t检验对保持后牙弓横向尺寸的变化进行统计学评估。
与未治疗的对照组相比，治疗组上颌磨牙间宽度（4.5mm）、尖牙间宽度（3.6mm）有统计学显著增加，后牙弓横向差异（4.2mm）和前牙弓横向差异（3.3mm）有显著改善。治疗组与对照组在下颌磨牙间和尖牙间宽度上未发现统计学显著差异。
扩弓板是乳牙列和早期混合牙列中扩大上颌牙弓的一种简单有效的装置。
