Baumrind S, Korn E L, West E E
Am J Orthod. 1984 Nov;86(5):371-85. doi: 10.1016/s0002-9416(84)90029-0.
An experiment was conducted in an attempt to determine empirically how effective a number of expert clinicians were at differentiating "backward rotators" from "forward rotators" on the basis of head-film information which might reasonably have been available to them prior to instituting treatment for the correction of Class II malocclusion. As a result of a previously reported ongoing study, pre- and posttreatment head films were available for 188 patients treated in the mixed dentition for the correction of Class II malocclusion and for 50 untreated Class II subjects. These subjects were divided into 14 groups (average size of group, 17; range, 6 to 23) solely on the basis of type of treatment and the clinician from whose clinic the records had originated. From within each group, we selected the two or three subjects who had exhibited the most extreme backward rotation and the two or three subjects who had exhibited the most extreme forward rotation of the mandible during the interval between films. The sole criterion for classification was magnitude of change in the mandibular plane angle of Downs between the pre- and posttreatment films of each patient. The resulting sample contained 32 backward-rotator subjects and 32 forward-rotator subjects. Five expert judges (mean clinical experience, 28 years) were asked to identify the backward-rotator subjects by examination of the pretreatment films. The findings may be summarized as follows: (1) No judge performed significantly better than chance. (2) There was strong evidence that the judges used a shared, though relatively ineffective, set of rules in making their discriminations between forward and backward rotators. (3) Statistical analysis of the predictive power of a set of standard cephalometric measurements which had previously been made for this set of subjects indicated that the numerical data also failed to identify potential backward rotators at a rate significantly better than chance. We infer from these findings that the ability of clinicians to identify backward rotators on the basis of information available at the outset of treatment is poor. Hence, we believe that it is unlikely that such predictions play any consequential operational role in the planning of successful orthodontic therapy at the present state of the art.
进行了一项实验，旨在根据在开始治疗Ⅱ类错牙合畸形之前临床医生合理可得的头影测量信息，通过实证研究确定一些专家临床医生在区分“向后旋转者”和“向前旋转者”方面的效果如何。作为之前一项正在进行的研究的结果，有188名在混合牙列期接受Ⅱ类错牙合畸形矫正治疗的患者以及50名未经治疗的Ⅱ类错牙合畸形受试者的治疗前和治疗后头影测量片。这些受试者仅根据治疗类型和记录来源的诊所医生分为14组（每组平均人数为17人；范围为6至23人）。从每组中，我们挑选出在两张头影测量片间隔期间下颌骨表现出最极端向后旋转的两三名受试者以及下颌骨表现出最极端向前旋转的两三名受试者。分类的唯一标准是每位患者治疗前和治疗后头影测量片中唐斯下颌平面角的变化幅度。最终样本包含32名向后旋转者和32名向前旋转者。邀请了五名专家评判员（平均临床经验28年）通过检查治疗前头影测量片来识别向后旋转者。研究结果总结如下：（1）没有一位评判员的表现显著优于随机水平。（2）有强有力的证据表明，评判员在区分向前旋转者和向后旋转者时使用了一套共同但相对无效的规则。（3）对之前针对这组受试者进行的一组标准头影测量指标的预测能力进行统计分析表明，数值数据识别潜在向后旋转者的比率也未显著优于随机水平。我们从这些研究结果推断，临床医生根据治疗开始时可得的信息识别向后旋转者的能力很差。因此，我们认为在目前的技术水平下，此类预测在成功的正畸治疗计划中不太可能发挥任何重要的实际作用。
