Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 13 4 2016 12 31 252 260 Hoorieh Bashizadeh Fakhar Assistant Professor, Department of Oral and Maxillofacial Radiology, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Elham Sadat Emadian Razavi Assistant Professor, Department of Orthodontics, Dental Faculty, Arak University of Medical Sciences, Arak, Iran Sepideh Soheilifar Assistant Professor, Department of Orthodontics, Dental Faculty, Hamedan University of Medical Sciences, Hamedan, Iran Mohammad Javad Kharazifard Statistical Consultant, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran 2016 11 08 Objectives: The purpose of this study was to develop and test a new tool for radiographic densitometry by combining periapical films and aluminum step wedge. Materials and Methods: We reviewed 50 Kodak E-speed intraoral films. An aluminum step wedge consisting of 16 steps was constructed. Each step was 1mmx3mx10mm. The step wedge was exposed to varying exposure times, ranging from 0.05 second to 0.5 second, increasing in 0.05 second increments. Films were digitalized after processing and the MATLAB software algorithm was ran subsequently. Density of the films was measured again using a digital densitometer. In order to compare the two imaging techniques, three steps were selected. Output data from the MATLAB algorithm were compared with data obtained from the digital densitometer. Results: The new method could detect significant differences between subsequent exposure times in step 7, while the densitometer did that in steps 7 and 12. The new method’s sensitivity in determining density changes was 5.26%, 84.1% and 93.02% in steps 2, 7, and 12 respectively. Conclusions: Our new method has an acceptable sensitivity for determining density changes of at least 7 mmEq/Al.   https://fid.tums.ac.ir/index.php/fid/article/view/1611 https://fid.tums.ac.ir/index.php/fid/article/download/1611/905