BLUR REDUCTION OF CONVENTIONAL FILM-BASED TOMOGRAMS FOR PRESURGICAL EVALUATION OF POTENTIAL MANDIBULAR IMPLANT SITES

THE USEFULNESS OF MOTION-BASED cross-sectional tomography to evaluate osseous support and adjacent anatomical structures for dental implant placement is limited by the inherent blurring in these images. The goa l of this study was to develop a method to remove blurring while permi tting accurate dimensional analysis of the potential implant site. Def ined regions (anterior, cuspid, premolar, molar) on two preserved huma n mandibles were imaged using cross-sectional linear tomography. Algor ithms were developed as a personal computer application to remove the blur and to aid in identification of the cortical plate borders and th e mandibular canal. The data set of eight tomograms was digitized and the blur reduced with the developed algorithm. An operator measured th e height and width of the mandible on each original tomogram and each deblurred tomogram in triplicate, Method error was calculated as the d ifference between direct caliper measurements of the respective skull regions and image measurements of height and width for both the origin al digitized tomograms and the deblurred tomograms. Method error using the original images (height: -2.72 +/- 2.15 mm; width: -0.58 +/- 1.36 mm) compared to the deblurred tomograms (height: -0.58 +/- 1.16 mm; w idth: 0.37 +/- 0.59 mm) was significantly greater for both height (t-t est level of significance, P = 0.0047) and width (t-test level of sign ificance, P = 0.0001). These findings suggest that the method develope d may greatly improve the ability of clinicians to accurately assess t he implant site using cross-sectional film-based linear tomograms.