Sinus inlay bone augmentation: comparison of implant positioning after one- or two-staged procedures

PURPOSE: This study was undertaken to compare implant angulation and position after one- or two-stage sinus inlay bone augmentation. PATIENTS AND METHODS: Twenty patients were retrospectively selected; group 1 (n = 10) was operated on with a one-stage procedure, and group 2 (n = 10) with a two-stage operation. Casts processed for the final permanent or temporary bridgework were collected and photographed from an oblique anterior view paralleling the alveolar crest on the right and left sides, as well as from an occlusal view. The angle between impression pins inserted in the abutments relative to the true vertical was recorded. In the occlusal view, the midpoints of the abutments were related to an individual computerized superimposed parabola. RESULTS: The implants inserted during the one-stage procedure were generally placed more palatally (Wilcoxon rank sum test, P = .0101) and angled more palatally (P = .0009) compared with those placed with the two-stage operation. CONCLUSION: This study showed that the two methods of treating patients by sinus inlay bone augmentation differed significantly with regard to placement and angulation of the implants. A two-stage procedure seems to offer the surgeon more optimal conditions for positioning the implants.