Film-based and Digital Imaging for Detection of Restorative Defects

Objective: To compare the accuracy of digital radiography systems with conventional techniques. There is little research comparing F-speed film with phosphor storage plates and CMOS sensors. Methods: Sixteen cadaver half-mandibles and maxillae were obtained from the Oral Biology department at UNMC College of Dentistry. Mesio-occlusal or disto-occlusal preparations were made in posterior teeth in each quadrant. A coin was flipped to determine whether or not a defect would be simulated under the restoration. Defects were created through the placement of approximately 0.5 mm of Aluwax in the gingival seat of the preparation. All preparations were filled with Sybralloy. The half-mandibles and maxillae were then imaged using D and F-speed film (Eastman Kodak), Optime phosphor storage plates (DIGORA), and a CMOS sensor (Kodak). The spatial geometry was held constant and the exposure times varied to obtain equalized densities. The images and denoted sites were read by dentists to diagnose the presence of defects. Evaluators read images of each respective technology in separate sittings, at least one week apart. The results for each quadrant were compared to determine the relative diagnostic success. Statistical analyses were performed using the MIXED procedure. Results: The percent accuracy in determining the presence of a defect was 78.2% for D-speed film, 74.4% for F-speed film, 74.4% for the CMOS sensor, and 84.6% for the phosphor storage plates. The percent accuracy in determining the absence of a defect was 66.7% for D-speed film, 83.3% for F-speed film, 94.7% for the CMOS sensor, and 64.9% for the phosphor storage plates. There was no statistical difference in diagnostic accuracy of these technologies (p=0.1625). Conclusion: When different technologies provide equal diagnostic accuracy, the decision between them can be based on the practitioner's preference in terms of comfort, confidence, or cost. Supported by UNMC COD Summer Student Research Fellowship grant FY07-07.