A Dynamic Navigation-Assisted Transcrestal Sinus Floor Elevation in Severely Atrophic Maxillae: A Descriptive Case Series.

BACKGROUND: Transcrestal sinus floor elevation (tSFE) and lateral window sinus floor elevation (lSFE) are established techniques for implant placement in the atrophic posterior maxilla. While lSFE is traditionally indicated for residual bone height (RBH) < 5 mm, tSFE offers the advantage of reduced surgical trauma but is typically limited to cases with RBH > 5 mm due to the lack of direct visualization, which can compromise membrane integrity and implant positioning accuracy. Dynamic computer-aided implant surgery (dCAIS) has been introduced to address these limitations, but its effectiveness in tSFE, particularly in severely resorbed ridges, requires further investigation. PURPOSE: The purpose of this study was to evaluate the accuracy of a dynamic navigation system for implant placement when performing simultaneous transcrestal sinus floor elevation in patients with severely atrophic posterior maxillae (RBH < 5 mm). MATERIALS AND METHODS: This study evaluated 24 implants placed in 12 patients who underwent simultaneous tSFE and implant placement using a dynamic navigation system. All patients presented with an RBH of less than 5 mm in the posterior maxilla. Implant accuracy was assessed by comparing the planned and final implant positions. Descriptive analysis was performed to calculate the mean global platform deviation, global apex deviation, angular deviation, and platform depth deviation. RESULTS: The descriptive analysis yielded the following mean accuracy values: global platform deviation (5.04 ± 2.06 mm), global apex deviation (4.71 ± 2.13 mm), angular deviation (2.24 ± 0.36°), and platform depth deviation (4.59 ± 2.16 mm). All 24 implants achieved successful osseointegration. CONCLUSION: Within the limitations of this study, the results suggest that tSFE with simultaneous implant placement using dynamic navigation is a feasible technique even in severely resorbed maxillae with RBH less than 5 mm. All implants osseointegrated successfully. However, the positional deviations observed were higher than those typically reported for dynamically navigated implant placement in less complex clinical scenarios, highlighting the significant technical challenges associated with combining tSFE and dCAIS in compromised bone.