Ferrario Virgilio F, Garattini Giovanna, Colombo Anna, Filippi Vittorio, Pozzoli Silvio, Sforza Chiarella
Functional Anatomy Research Center, Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatico, Dipartimento di Anatomia Umana, Facoltà di Medicina e Chirurgia, Università degli Studi di Milano, Italy.
Eur J Orthod. 2003 Aug;25(4):401-10. doi: 10.1093/ejo/25.4.401.
The present study analysed the six-month effects of a nickel-titanium (NiTi) palatal expander on the dental and palatal structures of four primary (mean age 5.8 years) and nine mixed dentition children (mean age 8.7 years), with a posterior unilateral crossbite. Standardized dental and palatal landmarks were digitized using a three-dimensional (3D) electromagnetic instrument. Collected data were analysed with geometric-mathematical models. During a six-month interval, the natural growth and development of the dental arches and hard tissue palate was negligible, as assessed in seven control children (two in the primary dentition, mean age 4.4 years; five in the mixed dentition, mean age 7.7 years). In all children the crossbite was completely corrected. Indeed, dental expansion was always more than or corresponded to the palatal expansion. A smoothing of the size-independent (shape) palatal curvature in the transverse plane was observed. No differences in maximum palatal height were noted. Symmetrical derotation of the anchorage teeth in a distal direction occurred in almost all children. The inclination of the facial axis of the clinical crown (FACC) in the anatomical transverse plane of those teeth with differences between dental and palatal expansion always showed significant modifications (vestibular inclination up to 16.7 degrees). The clinical crown height of anchorage teeth remained nearly the same in all patients. No significant modifications in mandibular arch size were observed. The increase in maxillary arch width, especially in younger children, was probably due to a combination of different effects: opening of the midpalatal suture, tipping of the alveolar process, and molar tipping.
本研究分析了镍钛（NiTi）腭扩展器对4名乳牙期儿童（平均年龄5.8岁）和9名混合牙列期儿童（平均年龄8.7岁）的牙齿和腭部结构的六个月影响，这些儿童均患有后牙单侧反牙合。使用三维（3D）电磁仪器对标准化的牙齿和腭部标志点进行数字化处理。收集的数据采用几何数学模型进行分析。在六个月的时间间隔内，通过对7名对照儿童（2名乳牙期儿童，平均年龄4.4岁；5名混合牙列期儿童，平均年龄7.7岁）的评估发现，牙弓和硬腭组织的自然生长发育可忽略不计。在所有儿童中，反牙合均得到完全矫正。事实上，牙齿扩展总是大于或等同于腭部扩展。观察到腭部在横向平面上与大小无关的（形状）曲率变得平滑。未发现腭部最大高度有差异。几乎所有儿童的支抗牙均向远中方向发生对称旋转。在牙齿扩展和腭部扩展存在差异的那些牙齿的解剖横向平面中，临床冠面部轴（FACC）的倾斜度总是显示出显著变化（前庭倾斜度高达16.7度）。所有患者中支抗牙的临床冠高度几乎保持不变。未观察到下颌牙弓大小有显著变化。上颌牙弓宽度的增加，尤其是在较年幼的儿童中，可能是由于多种不同作用的组合：腭中缝打开、牙槽突倾斜和磨牙倾斜。
