Tong Qian, Yang Xue, Fei Yue, Wang Jun
Department of Pediatric Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, China.
College of Stomatology, Shanghai Jiao Tong University, Shanghai 200125, China.
Children (Basel). 2025 May 19;12(5):653. doi: 10.3390/children12050653.
This retrospective study evaluated the short-term effects of removable slow maxillary expansion (SME) on eruption patterns of labially ectopic canines in a Chinese pediatric population, comparing treated patients with untreated controls. Seventy-six patients (mean age 8.38 ± 0.88 years) underwent SME treatment for 11.04 ± 4.44 months. Canine positions were categorized as labial ectopic (TE: = 40) or normally positioned (TN: 112). The TE group was stratified vertically: superior (TES; 15, canines above lateral incisors' roots or adjacent to unerupted incisors) and inferior (TEI; 25, canines adjacent to erupted lateral incisors' roots). Untreated controls ( 58; mean age 8.46 ± 0.78 years) included labial ectopic (CE group; 32) and normal canines (CN group; 84), with CE further divided vertically into CES ( 24) and CEI ( 8). Panoramic radiographs at baseline (T0) and follow-up (T1) evaluated sector distribution, midline proximity (3c-ML: canine cusp to midline distance), vertical position (3c-OP: cusp to occlusal plane distance), and angular (3^ML: canine-midline angle). SME significantly improved midline proximity (3c-ML increased) while reducing vertical height (3c-OP decreased) and angulation (3^ML reduced) in the TE group. Notably, TE patients revealed a significantly greater increase in 3c-ML compared to CE. Subgroup analysis showed that TEI canines exhibited significant improvements in all three parameters (3c-OP, 3c-ML, and 3^ML), whereas TES canines displayed minimal changes. The shifts in sector distribution were similar between the treatment and control groups. SME demonstrated short-term efficacy in guiding labially ectopic canines toward more favorable eruption trajectories, particularly when erupted beyond the roots of the lateral incisor. The observed positional improvements underscore SME's potential to optimize eruption outcomes during early orthodontic intervention.
这项回顾性研究评估了可摘式慢速上颌扩弓（SME）对中国儿童人群中唇侧异位尖牙萌出模式的短期影响，并将治疗患者与未治疗的对照组进行了比较。76名患者（平均年龄8.38±0.88岁）接受了11.04±4.44个月的SME治疗。尖牙位置分为唇侧异位（TE：=40）或正常位置（TN：112）。TE组按垂直方向分层：上位（TES；15，尖牙位于侧切牙根上方或与未萌出的切牙相邻）和下位（TEI；25，尖牙与已萌出的侧切牙根相邻）。未治疗的对照组（58名；平均年龄8.46±0.78岁）包括唇侧异位尖牙（CE组；32）和正常尖牙（CN组；84），CE组再按垂直方向分为CES（24）和CEI（8）。在基线（T0）和随访（T1）时的全景X线片评估了扇形分布、中线接近度（3c-ML：尖牙牙尖到中线的距离）、垂直位置（3c-OP：牙尖到咬合平面的距离）和角度（3^ML：尖牙-中线角度）。SME显著改善了TE组的中线接近度（3c-ML增加），同时降低了垂直高度（3c-OP降低）和角度（3^ML减小）。值得注意的是，与CE组相比，TE组患者的3c-ML增加显著更大。亚组分析表明，TEI尖牙在所有三个参数（3c-OP、3c-ML和3^ML）上均有显著改善，而TES尖牙变化最小。治疗组和对照组之间扇形分布的变化相似。SME在引导唇侧异位尖牙向更有利的萌出轨迹方面显示出短期疗效，特别是当尖牙萌出超过侧切牙根时。观察到的位置改善强调了SME在早期正畸干预期间优化萌出结果的潜力。
