Wenzel A
Department of Oral Radiology, Royal Dental College, University of Aarhus, Denmark.
Dentomaxillofac Radiol. 1998 Jan;27(1):3-11. doi: 10.1038/sj.dmfr.4600321.
Direct digital acquisition of intra-oral radiographs has been possible only in the last decade. Several studies have shown that, theoretically, there are a number of advantages of direct digital radiography compared with conventional film. Laboratory as well as controlled clinical studies are needed to determine whether new digital imaging systems alter diagnosis, treatment and prognosis compared with conventional methods. Most studies so far have evaluated their diagnostic performance only in laboratory settings. This review concentrates on what evidence we have for the diagnostic efficacy of digital systems for caries detection. Digital systems are compared with film and those studies which have evaluated the effects on diagnostic accuracy of contrast and edge enhancement, image size, variations in radiation dose and image compression are reviewed together with the use of automated image analysis for caries diagnosis. Digital intra-oral radiographic systems seem to be as accurate as the currently available dental films for the detection of caries. Sensitivities are relatively high (0.6-0.8) for detection of occlusal lesions into dentine with false positive fractions of 5-10%. A radiolucency in dentine is recognised as a good predictor for demineralisation. Radiography is of no value for the detection of initial (enamel) occlusal lesions. For detection of approximal dentinal lesions, sensitivities, specificities as well as the predictive values are fair, but are very poor for lesions known to be confined to enamel. Very little documented information exists, however, on the utilization of digital systems in the clinic. It is not known whether dose is actually reduced with the storage phosphor system, or whether collimator size is adjusted to fit sensor size in the CCD-based systems. There is no evidence that the number of retakes have been reduced. It is not known how many images are needed with the various CCD systems when compared with a conventional bitewing, nor how stable these systems are in the daily clinical use or whether proper cross-infection control can be maintained in relation to scanning the storage phosphor plates and the sensors and the cable. There is only sparse evidence that the enhancement facilities are used when interpreting images, and none that this has changed working practices or treatment decisions. The economic consequences for the patient, dentist and society require examination.
口腔内X光片的直接数字采集仅在过去十年才成为可能。多项研究表明，从理论上讲，直接数字放射成像与传统胶片相比有许多优势。需要进行实验室研究以及对照临床研究，以确定与传统方法相比，新的数字成像系统是否会改变诊断、治疗和预后。到目前为止，大多数研究仅在实验室环境中评估了它们的诊断性能。本综述集中于我们所拥有的关于数字系统在龋齿检测方面诊断效力的证据。将数字系统与胶片进行比较，并对那些评估了对比度和边缘增强、图像大小、辐射剂量变化以及图像压缩对诊断准确性的影响的研究，以及使用自动图像分析进行龋齿诊断的研究进行综述。数字口腔内X光成像系统在检测龋齿方面似乎与目前可用的牙科胶片一样准确。对于检测到牙本质中的咬合面病变，灵敏度相对较高（0.6 - 0.8），假阳性率为5 - 10%。牙本质中的透射区被认为是脱矿的良好预测指标。X光摄影对于检测初始（釉质）咬合面病变没有价值。对于检测邻面牙本质病变，灵敏度、特异性以及预测值都尚可，但对于已知局限于釉质的病变则非常差。然而，关于数字系统在临床中的应用，记录在案的信息很少。尚不清楚存储磷光体系统是否真的降低了剂量，或者基于电荷耦合器件（CCD）的系统中准直器大小是否根据传感器大小进行了调整。没有证据表明重拍次数有所减少。与传统咬合翼片相比，不同的CCD系统需要拍摄多少张图像尚不清楚，这些系统在日常临床使用中的稳定性如何，以及在扫描存储磷光板、传感器和电缆时能否维持适当的交叉感染控制也不清楚。仅有稀少的证据表明在解读图像时使用了增强设施，而且没有证据表明这改变了工作方式或治疗决策。对患者、牙医和社会的经济影响需要进行研究。
