Establishment of prognostic evaluation of dental implants by standardized digital radiography

本研究的目的是确定使用数字放射照相系统进行放射照相的最佳辐射剂量和图像处理条件，开发辅助仪器，允许使用该数字放射照相系统进行安全、简单和几何上可重复的放射照相，以评估使用该数字放射照相系统的植入结果，并评估数字减影的可能性。将种植体固定在尸体下颌骨的磨牙缺陷中，在固定体周围产生1-3 mm的骨缺损，使用数字x线摄影系统（Digora）和牙科x线片（Ektaspeed Plus）进行x线摄影检查。Digora可以在0.5秒的放射时间内检测到2mm或以上的骨缺损，并且在灵敏度、特异性和准确性方面优于Ektaspeed Plus。即使在将辐射剂量减少到1/5后，检测能力也没有明显下降，这表明可能会减少剂量。作为标准x线摄影的辅助工具，面弓转移用于咬合配准得到了改进，并且可重复x线摄影成为可能。x线摄影采用直接数字系统（CDR），在干燥颅骨的磨牙区放置一些类型的骨片，以增加骨变化。使用具有自动叠加功能的数字减法软件（Emago）对每张图像进行减法。图像评价显示CDR比常规牙片准确度更高。该方法采用数字减法软件（Emago）和我们的新辅助仪器，可用于连续观察种植体的结果。

The purpose of this study was to determine the optimal radiation dose and image processing conditions for radiography using a digital radiographic system, develop auxiliary instruments allowing safe, simple, and geometrically reproducible radiography for the assessment of implant outcomes using this digital radiographic system and evaluate the possibility of digital subtraction. Implant fixtures were inserted into molar defects of cadaver mandibular bone, and bone defects (1-3 mm) were produced around the fixture and examined by radiography using a digital radiographic system (Digora) and dental X-ray films (Ektaspeed Plus). The Digora allowed detection of bone defects of 2 mm or more with a radiation time of 0.5 seconds and was superior to the Ektaspeed Plus in terms of sensitivity, specificity, and accuracy. Even after a reduction of the radiation dose to 1/5, the detection ability did not markedly decrease, suggesting that a reduction in dose is possible. As auxiliary instruments for standard radiography, the face-bow transfer used for occlusal registration was improved, and reproducible radiography became possible. For radiography, a direct digital system (CDR) was used, and some types of bone chips were placed in the molar area of dry skulls so as to add bone changes. On each image, subtraction was performed using software for digital subtraction (Emago) with automatic superposition function. Evaluation of images showed a higher accuracy of the CDR than conventional dental films. This method using software for digital subtraction (Emago ) and our new auxiliary instrument may be useful for serial observation of implant outcomes.