['The purpose of this study was to evaluate the efficacy of conventional cross-sectional tomography in predicting the appropriate implant size.', 'The implant length and width of 46 patients referred for single tooth implant treatment were determined presurgically by periapical + panoramic images (record 1) and after surgery by periapical + panoramic images + tomograms (record 2). These dimensions were compared with the dimensions of the implants actually installed (record 3), as well as the dimensions assessed to be the "appropriate" ones according to defined criteria for success (record 4).', 'In 70% of the cases, the implant length or width, or both, was changed after the tomogram was available. The implant dimensions determined with tomography were maintained at surgery in 87% of the cases. In only 33% of the cases did the implant size predicted without tomography correspond with the size of the installed implants. The agreement between records 2 and 3 was significantly higher than between records 1 and 3 (P < .001). Similarly, the agreement between records 2 and 4 was significantly higher than between records 1 and 4 (P < .001).'] Do impact of conventional tomography on prediction of the appropriate implant size?