Kang Yunlong, Franchi Lorenzo, Manton David J, Schneider Paul M
Melbourne Dental School, University of Melbourne, Australia.
Department of Surgery and Translational Medicine, Unit of Orthodontics, Università degli Studi di Firenze, Firenze, Italy.
Eur J Orthod. 2018 Apr 6;40(2):164-175. doi: 10.1093/ejo/cjx044.
To analyse the skeletal and dento-alveolar effects of the modified Louisiana State University activator (MLSUA) in Class II treatment.
A test group of 46 participants (25 females, 21 males) with Class II malocclusion treated with MLSUA followed by fixed appliances was compared with a matched Class II control group. Lateral cephalograms were taken at T1 (initial records), T2 (completion of MLSUA treatment), and T3 (before deband). The participants were also divided into two groups: pre-pubertal and pubertal according to skeletal maturity and three groups of different vertical facial patterns at the start of the treatment: brachyfacial, mesofacial, and dolichofacial. Statistical comparisons were performed with t-tests and analysis of variance (ANOVA).
Statistically significant supplementary mandibular growth (Co-Gn) in the test group (2.6 mm) was associated with improvement of overjet (OJ), overbite (OB), and molar relationship. Short-term mandibular growth was greater in pubertal than pre-pubertal groups (2.4 mm, P < 0.05). Mandibular incisors retroclined by 2.1 degrees after MLSUA treatment. The brachyfacial group showed greater reduction in the ANB angle and forward movement of pogonion. Mandibular, palatal, and occlusal plane angles showed insignificant change regardless of the facial type.
MLSUA treatment corrected the Class II malocclusion by accelerating mandibular growth in the short-term with minimal dento-alveolar compensation, and the correction was maintained before deband. The treatment may be more effective if started at puberty. The mandibular, palatal, and occlusal planes remained stable throughout the treatment. Brachyfacial patients showed more favourable horizontal growth.
分析改良路易斯安那州立大学矫治器（MLSUA）在安氏II类错颌治疗中的骨骼和牙-牙槽效应。
将46例接受MLSUA治疗后再使用固定矫治器的安氏II类错颌患者（25例女性，21例男性）组成的试验组与匹配的安氏II类对照组进行比较。在T1（初始记录）、T2（MLSUA治疗完成时）和T3（拆除矫治器前）拍摄头颅侧位片。根据骨骼成熟度将患者分为两组：青春期前和青春期，治疗开始时根据不同垂直面型分为三组：短面型、平均面型和长面型。采用t检验和方差分析（ANOVA）进行统计学比较。
试验组下颌有统计学意义的额外生长（Co-Gn为2.6mm）与覆盖（OJ）、覆合（OB）和磨牙关系的改善相关。青春期组的短期下颌生长大于青春期前组（2.4mm，P<0.05）。MLSUA治疗后下颌切牙向后倾斜2.1度。短面型组ANB角减小和颏点前移更明显。无论面型如何，下颌、腭和咬合平面角变化不显著。
MLSUA治疗通过在短期内加速下颌生长并以最小的牙-牙槽代偿来纠正安氏II类错颌，且在拆除矫治器前矫治效果得以维持。如果在青春期开始治疗可能更有效。整个治疗过程中下颌、腭和咬合平面保持稳定。短面型患者水平向生长更有利。
