Subtraction radiography in oral implantology.

Radiographic examinations in connection with implant installation are important means to diagnose changes in the bone tissue following implantation. During the healing and early remodeling phases, a slight reduction of the marginal bone height occurs in the first year after implantation, which is followed by an even smaller annual mean loss in bone height. Conventional radiographs, however, are of limited value for reliable assessment of subtle alveolar bone changes, although methods were developed to standardize the projection geometry of serial radiographs from implants to improve the accuracy in detecting changes of the peri-implant bone height. Newer radiographic diagnostic methods should not only comprise the possibility of metric assessment of bone height but also further information on changes in density. This report emphasizes the potential of digital subtraction radiography as a sensitive diagnostic tool in peri-implant diagnosis. Minute peri-implant density changes may occur in the healing phase after implant installation, after loading, and during the maintenance phase.