CALIBRATION OF DIGITAL PHOTOGRAPHY AND SPECIFIC SOFTWARE FOR MEASUREMENTS ON LOWER OVERDENTURES WITH TWO SPHERICAL ATTACHMENTS.

OBJECTIVE. To establish a system of measurement by analysis of standardized images to evaluate the equidistance between clips in models obtained with different clinical printing techniques. METHODS. A support structure was made for photographing by providing a fixed attachment medium for the Nikon SLR camera model 5200 and the cast models obtained with different clinical printing techniques. So that the photographs obtained had the same focal length and center or focus equidistant from Both pins. Then, two photographs were taken per model, on three different days, and the distances for each model were measured using the software imagetool of the univ of texas, making at the same time three measurements for each photo obtained. Then the averages of each photo were calculated and the measurements were purchased from each other. RESULTS. When analyzing the differences between the values ??obtained in the first 6 photos of each model, a significant and clinically relevant difference between them was found, with an intra-model difference amplitude of 1.53 mm. The measurements were then repeated by modifying the camera focus system, eliminating the autofocus, obtaining new photographs and measurements, and reducing the difference to 0.22 mm, a clinically acceptable value for the objectives of the study. CONCLUSION. Although the reference literature makes no mention of the influence of autofocus on photographic taking for linear measurements with imagetool, in this calibration work establishing the fixed focus provided reproducible and stable intra-model measurement values.