Department of Oral Diagnosis and Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey.
Dent Traumatol. 2010 Feb;26(1):47-51. doi: 10.1111/j.1600-9657.2009.00841.x.
To determine the effects of digital image enhancement on observer ability to detect experimentally induced vertical root fractures (VRF).
A total of 64 extracted human mandibular premolar teeth were used in this study. In 32 teeth, VRFs were created in the bucco-lingual planes by gently tapping with screw-type root-canal pins. The remaining 32 intact teeth served as a control group. Digital images were obtained using a charge coupled device sensor. Three observers separately examined the original and four types of digitally enhanced images (enhanced using sharpness, zoom-in, reverse-contrast, and pseudo-3D functions) at 1-week intervals. All teeth were evaluated using a 5-point scale for the presence/absence of VRF. Evaluations of each image set were repeated 1 month after the initial viewings. Kappa coefficients were calculated to investigate the degree of intra- and inter-observer agreement. The areas under the receiver operating characteristic (ROC) curves (Az values) were calculated using the MedCalc statistical software. ROC values for each image type, observer and viewing were compared using t-tests. A level of alpha = 0.05 was considered significant.
Kappa coefficients for intra-observer agreement ranged from 0.304 to 0.679. Inter-observer agreement kappa values ranged from 0.109 to 0.399 for the first reading and from 0.106 to 0.380 for the second reading. Statistical comparisons between Az values for each observer showed no significant differences (P > 0.05) among image types.
There were no differences in diagnostic outcomes among differently enhanced images in the in vitro detection of VRF.
确定数字图像增强对检测实验诱导的垂直根折（VRF）的观察者能力的影响。
本研究共使用 64 颗离体下颌前磨牙。在 32 颗牙齿中，通过轻轻敲击螺丝式根管针在颊舌平面上创建 VRF。其余 32 颗完整的牙齿作为对照组。使用电荷耦合器件传感器获得数字图像。三位观察者分别在 1 周的间隔时间内检查原始图像和四种类型的数字增强图像（使用锐度、放大、反转对比度和伪 3D 功能增强）。所有牙齿均使用 5 分制评估 VRF 的存在/缺失。在初始查看后 1 个月重复评估每个图像集。计算kappa 系数以研究观察者内和观察者间的一致性程度。使用 MedCalc 统计软件计算接收器操作特性（ROC）曲线下的面积（Az 值）。使用 t 检验比较每种图像类型、观察者和观察的 ROC 值。将 alpha 水平设为 0.05 认为具有统计学意义。
观察者内一致性的 kappa 系数范围为 0.304 至 0.679。第一次阅读的观察者间一致性 kappa 值范围为 0.109 至 0.399，第二次阅读的 kappa 值范围为 0.106 至 0.380。每位观察者的 Az 值之间的统计比较显示，图像类型之间的诊断结果没有差异（P > 0.05）。
在体外检测 VRF 中，不同增强的图像在诊断结果上没有差异。
