Radiographic analysis of the transcrestal sinus floor elevation: Short-term observations

Background: There are some limitations for implant placement in the posterior maxilla when there is an extended sinus. Various techniques for sinus floor elevation allow an increase in implant length. Purpose: The aim of the present radiographic study was to assess the augmented site in the sinus around implants that were installed by means of an osteotome-mediated transcrestal sinus floor elevation. Materials and Methods: Thirty-three patients with 44 implants were available. In 39% of the implants the sinus floor elevation was performed exclusively with bone chips. Bone fill material (Bio-Oss(R), Geistlich Sohne AG, Wolhusen, Switzerland) was additionally used to increase the volume and stability of the lifted area at 61% of the implants. The visibility and morphology of the augmentation were assessed and compared by means of intraoral radiography (long-cone technique). Results: All implants were stable and were considered to be successful when they were reexamined in the context of the present study. The mean residual bone height was 5.78 +/- 1.4 mm. The increase of the implant length as compared to the original bone height resulted in a mean value of 3.87 +/- 2.0 mm. The volume and density of the lifted area were more visible if Bio-Oss was added. A shrinkage and/or condensation of the grafted material was visible at 37% of the implants after a minimum loaded period of 200 days. Equally, a decreased visibility of the original sinus floor was noted at 61% of implants. The formation of a cortical bone layer at the apex of the implants was detected at 35% of implants. Conclusions: The surgical procedure appears to be a safe method with rare complications. Radiographic assessment of the augmentation procedure proved to be difficult, and measurements are not fully reliable.