THE ACCURACY OF DENTAL RADIOGRAPHIC TECHNIQUES USED FOR EVALUATION OFIMPLANT FIXTURE PLACEMENT

Periapical, panoramic, linear tomographic, and computerized tomographi c radiographs were made of a partially dentate human mandible with fou r implants in place. Measurements taken from the radiographs and compu ter-generated images were compared to measurements made directly on th e cross-sectioned test specimen. Periapical radiographs produced the m ost accurate measurements. Computerized and linear tomographic images provided the unique advantage of cross-sectional views of anatomic str uctures, but image blurring inherent to linear tomography and volume-a veraging error inherent to computerized tomography affected the accura cy of measurements made from these images. The use of a dense dimensio nal reference object helped to compensate for radiographic distortion and is appropriate when projection radiographic techniques are used. T he CT reference scale provided the most accurate method for interpreti ng measurements made from the computerized tomogram. The use of a dens e dimensional reference object is inappropriate with CT because of ifs volume-averaging error.