EARLY VS LATE TREATMENT IN CLASS II MALOCCLUSION

10%的美国儿童患有II类咬合不正（“buck 牙齿”），近一半的正畸患者接受治疗， 这类问题。原因通常是下巴不成比例的生长， 最好的治疗方法仍然未知。选择还很早 治疗（青春期前），试图修改生长和纠正 下颌关系，或以后的治疗（在青春期）重新定位 牙齿，以弥补不正确的下巴位置。重要 问题是是否可以实现生长修饰，如果可以， 是否会对后续治疗和结果产生影响。一 前瞻性随机临床试验（RCT），我们现在正在进行 比较头帽与功能矫治器早期治疗的方法 与没有早期治疗相比，需要获得公正的答案。 我们 也在解决更多的问题和更广泛的年龄覆盖面 通过更大的回顾性-前瞻性观察样本， II类患者。 目前，最初指定的150名儿童已在 RCT; 107已经完成了第一阶段，其余的将在年底完成 的当前时期。初步数据表明，这两种类型的 早期治疗影响生长。 所有这些孩子都需要第二阶段 已开始对68名患者进行治疗，但迄今已完成 只有两个。该项目目前的一个主要目标是完成第二阶段 RCT患者的治疗，比较2期结束时的结局 与那些没有接受早期治疗的人相比。长期 结果很大程度上受到如何管理治疗后保留的影响， 在RCT患者中，我们将比较常规 单牙弓正畸固位器和改进的功能性矫治器 保持器。最后，使用更大的观察组来获得更广泛的 患者覆盖率，用于与RCT结果进行比较，并提供数据 至于需要较长时间回答的问题，我们会评估 II类治疗的有效性和治疗后骨骼和 治疗后的牙齿变化没有类似的研究 进行。这些数据将阐明解决这些问题的最佳方法， 将在国内和国际上决定治疗方法 方式。

Ten percent of American children have Class II malocclusion ("buck teeth"), and nearly half of all orthodontic patients are treated for a problem of this type. The cause usually is disproportionate jaw growth, and the best treatment approach remains unknown. The choices are early treatment (prior to adolescence) to try to modify growth and correct the jaw relationship, or later treatment (in adolescence) to reposition the teeth to compensate for the incorrect jaw position. The important questions are whether growth modification can be accomplished, and if so, whether it makes any difference to subsequent treatment and outcomes. A prospective randomized clinical trial (RCT), which we now have in progress to compare headgear and functional appliance methods of early treatment versus no early treatment, is necessary to obtain unbiased answers. We also are addressing additional questions and a broader coverage of age groups through a larger retrospective-prospective observational sample of Class II patients. At this point, the 150 children specified initially have been enrolled in the RCT; 107 have finished phase 1 and the remainder will do so by the end of the current period. The preliminary data indicate that both types of early treatment affect growth. All these children require phase 2 treatment, which has begun for 68 patients but has been completed so far for only two. A major goal of the project now is to complete phase 2 treatment for RCT patients, comparing the outcomes at the end of phase 2 for those who had early treatment versus those who did not. Long-term outcomes are greatly affected by how posttreatment retention is managed, and in the RCT patients, we will compare the effectiveness of conventional uni-arch orthodontic retainers and a modified functional appliance as a retainer. Finally, using the larger observational group to obtain broader patient coverage for comparison with the RCT results and to provide data on questions that require a longer time span, we will evaluate the effectiveness of Class II treatment and the posttreatment skeletal and dental changes following treatment. No similar study has ever been undertaken. The data will clarify the best approach to these problems, and will be important nationally and internationally in determining treatment modalities.