Pandis Nikolaos, Polychronopoulou Argy, Eliades Theodore
Department of Community and Preventive Dentistry, School of Dentistry, University of Athens, Athens, Greece.
Am J Orthod Dentofacial Orthop. 2007 Aug;132(2):208-15. doi: 10.1016/j.ajodo.2006.01.030.
The aim of this study was to investigate the duration of mandibular-crowding alleviation with self-ligating brackets compared with conventional appliances and the accompanying dental effects.
Fifty-four subjects were selected from a pool of patients satisfying the following inclusion criteria: nonextraction treatment in the mandibular or maxillary arches; eruption of all mandibular teeth; no spaces in the mandibular arch; irregularity index greater than 2 in the mandibular arch; and no therapeutic intervention planned with any extraoral or intraoral appliance. The patients were randomly assigned to 2 groups: 1 group received treatment with a self-ligating bracket (Damon 2, Ormco, Glendora, Calif) and the other with a conventional edgewise appliance (Microarch, GAC, Central Islip, NY), both with 0.022-in slots. The irregularity index of the mandibular arch was normalized between the groups, and the time to alignment was estimated in days. Treatment duration was assessed by data modeling with the Cox proportional hazard regression. Lateral cephalometric radiographs were used to assess the alteration of mandibular incisor position before and after alignment. Measurements of intercanine and intermolar widths were also made on dental casts to determine changes associated with correction.
Overall, no difference in the time required to correct mandibular crowding with Damon 2 and conventional brackets was observed. For moderate crowding (irregularity index <5), however, the self-ligating group had 2.7 times faster correction. This difference was marginally insignificant for subjects with irregularity index scores greater than 5. Greater crowding prolonged treatment by an additional 20% for each irregularity index unit. Increases in intercanine and intermolar widths associated with crowding correction regardless of bracket group were noted. The self-ligating group showed a statistically greater intermolar width increase than the conventional group. Also, an alignment-induced increase in the proclination of the mandibular incisors was observed for both bracket groups, but no difference was found between Damon 2 and conventional brackets for this parameter.
本研究的目的是调查与传统矫治器相比，使用自锁托槽减轻下颌拥挤的持续时间以及伴随的牙齿效应。
从满足以下纳入标准的患者群体中选取54名受试者：下颌或上颌牙弓不拔牙矫治；所有下颌牙齿萌出；下颌牙弓无间隙；下颌牙弓不规则指数大于2；且未计划使用任何口外或口内矫治器进行治疗干预。患者被随机分为2组：1组接受自锁托槽（Damon 2，奥美科公司，加利福尼亚州格伦多拉）治疗，另一组接受传统方丝弓矫治器（Microarch，GAC公司，纽约州中央伊斯利普）治疗，两者均为0.022英寸槽沟。使两组之间下颌牙弓的不规则指数标准化，并以天数估计排齐时间。通过Cox比例风险回归的数据建模评估治疗持续时间。使用头颅侧位X线片评估排齐前后下颌切牙位置的改变。还在石膏模型上测量尖牙间和磨牙间宽度，以确定与矫治相关的变化。
总体而言，未观察到使用Damon 2自锁托槽和传统托槽矫治下颌拥挤所需时间的差异。然而，对于中度拥挤（不规则指数<5），自锁托槽组的矫治速度快2.7倍。对于不规则指数得分大于5的受试者，这种差异微乎其微。拥挤程度越高，每增加一个不规则指数单位，治疗时间延长20%。无论托槽类型如何，均注意到与拥挤矫治相关的尖牙间和磨牙间宽度增加。自锁托槽组磨牙间宽度增加在统计学上大于传统组。此外，两组托槽均观察到排齐导致下颌切牙前倾增加，但在该参数上Damon 2自锁托槽和传统托槽之间未发现差异。
