Ugolini Alessandro, Doldo Tiziana, Ghislanzoni Luis T Huanca, Mapelli Andrea, Giorgetti Roberto, Sforza Chiarella
Department of Orthodontics, University of Siena, Siena, Italy.
Functional Anatomy Research Center (FARC), Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatico (LAFAS), Dipartimento di Scienze Biomediche per la Salute, Facoltà di Medicina e Chirurgia, Università degli Studi di Milano, Milan, Italy.
Prog Orthod. 2016;17:1. doi: 10.1186/s40510-015-0114-9. Epub 2016 Jan 8.
The purpose of this controlled study was to investigate indirect effects on mandibular arch dimensions, 1 year after rapid palatal expansion (RPE) therapy.
Thirty-three patients in mixed dentition (mean age 8.8 years) showing unilateral posterior crossbite and maxillary deficiency were treated with a RPE (Haas type) cemented on the first permanent molars. Treatment protocol consisted of two turns per day until slight overcorrection of the molar transverse relationship occurred. The Haas expander was kept on the teeth as a passive retainer for an average of 6 months. Study models were taken prior (T1) and 15 months on average (T2) after expansion. A control group of 15 untreated subjects with maxillary deficiency (mean age 8.3 years) was also recorded with a 12-month interval. Stone casts were digitized with a 3D scanner (3Shape, DK).
In the treated group, both mandibular intermolar distance (+1.9 mm) and mandibular molar angulation (+9°) increased. Mandibular incisor angulation showed an increase of 1.9°. There was little effect on intercanine distance and canine angulation. Controls showed a reduction in transverse arch dimension and a decrease in molar and canine angulation values.
RPE protocol has indirect widening effects on the mandibular incisors and first molars.
本对照研究的目的是调查快速腭扩展（RPE）治疗1年后对下颌牙弓尺寸的间接影响。
33例处于混合牙列期（平均年龄8.8岁）、表现为单侧后牙反合及上颌发育不足的患者，采用粘结于第一恒磨牙上的RPE（哈斯型）进行治疗。治疗方案为每天转动2次，直至磨牙横向关系出现轻微过矫正。哈斯扩弓器作为被动保持器平均保留在牙齿上6个月。在扩弓前（T1）和扩弓后平均15个月（T2）制取研究模型。还对15例未经治疗的上颌发育不足受试者（平均年龄8.3岁）组成的对照组每隔12个月进行记录。用三维扫描仪（3Shape，丹麦）对石膏模型进行数字化处理。
治疗组下颌磨牙间距离增加了1.9mm，下颌磨牙倾斜度增加了9°。下颌切牙倾斜度增加了1.9°。对尖牙间距离和尖牙倾斜度影响较小。对照组的横向牙弓尺寸减小，磨牙和尖牙倾斜度值降低。
RPE治疗方案对下颌切牙和第一磨牙有间接的扩宽作用。
