Detection of peri-implant bone changes with axial tomosynthesis

Tuned aperture computed tomography was used to assess bone defects at implant sites that are normally obscured in conventional periapical projections. Titanium implants were placed in incisor, premolar, and molar areas of an edentulous dry human mandible. The alveolar crest adjacent to each implant was circumferentially grooved with progressively larger round burs (no. 1/4 to no. 6). After each increment of bone removal, axial tuned aperture computed tomography slice images were produced. From these, digital subtraction images were generated with incremental and baseline slices. A panel of eight dentists reviewed randomized pairs of images that showed defects that differed by a single bur size. Images were masked to limit observation to mesial, distal, facial, or lingual regions. Observers accurately identified larger lesions in 76% of the unsubtracted tuned aperture computed tomography images and in 90% of the subtracted images. Logistic regression analysis suggested significant differences as a result of lesion size (p < 0.036) and imaging modality (p < 0.020).