Division of Orthodontics, Faculty of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Division of Pediatric Dentistry, Faculty of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Am J Orthod Dentofacial Orthop. 2018 Oct;154(4):524-534. doi: 10.1016/j.ajodo.2018.01.011.
The purpose of this study was to evaluate the short-term impact of rapid maxillary expansion (RME) on the eruption paths of ectopically and normally erupting maxillary canines in the mixed dentition.
Thirty-two patients with 49 ectopically erupting canines (EEC group; age, 9.53 ± 1.10 years) and 18 patients with 27 normally erupting canines (NEC group; age, 9.25 ± 1.06 years) underwent RME. Thirty-six subjects with 54 normally erupting canines composed the untreated control group (UC group; age, 9.03 ± 0.72 years). Horizontal, vertical, and angular positions of canines and adjacent teeth were evaluated in the expanded (EEC and NEC groups) and unexpanded (UC group) patients using panoramic radiographs taken at 2 times with a 1-year interval. The radiographic evaluation methods included score ranking and proportional measurements to minimize panoramic radiograph limitations. Statistical comparisons were performed among the groups (P <0.05).
Before expansion, the EEC group's canines were significantly closer to the midline, more distant from the occlusal plane, and more mesially angulated than those in the UC group. After expansion, the canine positions in the EEC and UC groups were similar, whereas the NEC group had a more favorable canine position for eruption. The EEC and NEC groups showed similar canine positional changes, whereas the UC group had the smallest changes. The positions of teeth adjacent to the canine were also significantly affected by RME, and these changes may be associated with improvement of the ectopic canine position.
The changes produced by RME reduced the percentage of ectopic eruption paths and maintained the nonectopic eruption percentage.
本研究旨在评估快速上颌扩张（RME）对上颌恒尖牙在混合牙列中异位和正常萌出路径的短期影响。
32 名 49 颗异位萌出尖牙患者（EEC 组；年龄，9.53±1.10 岁）和 18 名 27 颗正常萌出尖牙患者（NEC 组；年龄，9.25±1.06 岁）接受 RME。36 名 54 颗正常萌出尖牙的受试者构成未治疗对照组（UC 组；年龄，9.03±0.72 岁）。使用间隔 1 年拍摄的 2 次全景片，在扩张（EEC 和 NEC 组）和未扩张（UC 组）患者中评估尖牙和相邻牙齿的水平、垂直和角度位置。放射学评估方法包括评分排名和比例测量，以最大程度减少全景片的局限性。在组间进行了统计学比较（P<0.05）。
在扩张前，EEC 组的尖牙更靠近中线，与牙合平面更远，更向近中倾斜，与 UC 组相比。扩张后，EEC 和 UC 组的尖牙位置相似，而 NEC 组的尖牙位置更有利于萌出。EEC 和 NEC 组的尖牙位置变化相似，而 UC 组的变化最小。尖牙相邻牙齿的位置也受到 RME 的显著影响，这些变化可能与异位尖牙位置的改善有关。
RME 产生的变化减少了异位萌出路径的百分比，并保持了非异位萌出的百分比。
