Department of Orthodontics, São Paulo Methodist University, São Bernardo do Campo, Brazil.
Eur J Orthod. 2014 Apr;36(2):192-9. doi: 10.1093/ejo/cjt026. Epub 2013 Jun 4.
To examine the long-term effects induced by treatment with the function regulator (FR-2) appliance 7 years post-treatment compared with untreated class II subjects.
The FR-2 sample was collected prospectively and comprised 17 subjects (10 boys and 7 girls, mean age 10.8 years) who were treated with the FR-2 appliance for 1.7 years and re-evaluated 7.1 years after treatment. The step-by-step mandibular advancement was performed gradually (increments up to 3-4 mm), until a 'super class I' molar relationship was obtained. The control group consisted of 17 class II subjects (9 boys and 8 girls, mean age 11.3 years) with class II malocclusion, excessive overjet, and class II molar relationship, matched to the treated group as to ages at all times, gender distribution, and stages of skeletal maturity (evaluated by the cervical vertebral maturation method). The lateral cephalograms were analysed at T1 (initial), T2 (final), and T3 (7.1 years post-treatment). The compatibility between the groups and the comparisons of their changes at T1-T2, T2-T3, and T1-T3 intervals were examined by independent sample t-tests (P < 0.05).
FR-2 treatment provided a significant improvement in the maxillomandibular relationship due to an increase in mandibular length compared with controls, which remained stable over time. Also overjet, overbite, and molar relationship corrections demonstrated stability. Among dentoalveolar changes, only the increased mesial movement of the mandibular molars in the FR-2 group demonstrated stability.
Correction of class II malocclusion remained stable 7 years after FR-2 treatment mainly due to the stability of the skeletal changes.
比较 FR-2 功能调节器治疗 7 年后与未经治疗的 II 类错（牙合）患者的长期疗效。
FR-2 样本为前瞻性收集，包括 17 名受试者（10 名男孩，7 名女孩，平均年龄 10.8 岁），用 FR-2 矫治器治疗 1.7 年，治疗后 7.1 年重新评估。下颌逐步前伸，逐渐增加（增量达 3-4mm），直到获得“超 I 类”磨牙关系。对照组包括 17 名 II 类错（牙合）患者（9 名男孩，8 名女孩，平均年龄 11.3 岁），具有 II 类错（牙合）、过度覆（牙合）、II 类磨牙关系，与治疗组在各时间点的年龄、性别分布和骨骼成熟度（颈椎成熟度法评估）相匹配。在 T1（初始）、T2（最终）和 T3（治疗后 7.1 年）拍摄侧位头颅侧位片。通过独立样本 t 检验（P<0.05）比较两组的可比性和 T1-T2、T2-T3 和 T1-T3 时间间隔的变化。
FR-2 治疗通过增加下颌长度使上下颌关系得到显著改善，与对照组相比，这一效果在随访中保持稳定。同时，覆（牙合）、覆盖和磨牙关系的矫正也保持稳定。在牙颌变化中，只有 FR-2 组下颌磨牙的近中移动增加保持稳定。
FR-2 治疗 7 年后 II 类错（牙合）的矫正保持稳定，主要是由于骨骼变化的稳定性。
