National Taiwan University Hospital Taipei, Taipei, Taiwan (Republic of China)
Introduction: When the implant area with an insufficient bone height of the maxillary sinus, transcrestal or lateral window sinus floor elevation is indicated. In reviews of previous studies, sinus membrane perforation is the most common intraoperative complication. However, the anatomical limit of the maxillary sinus makes antrostomy and membrane elevation riskier. Besides, the limitation of visualization during transcrestal sinus floor elevation makes sinus lifting more challenging. Therefore, our study aimed to evaluate the outcomes of sinus floor elevation by using dynamic navigation to assist in performing osteotomy and antrostomy.
Methods: Fifteen healthy patients needed implant reconstruction over the posterior maxilla with vertical bone height under 10 mm. Before surgery, checked cone-beam computerized tomography (CBCT) and digital planning were completed. Subjects were arranged into transcrestal sinus floor elevation group when the initial vertical bone height was from 6 to 10 mm or lateral window sinus floor elevation group when the initial vertical bone height was under 6 mm. One surgeon (T.-Y. Lin) used the same protocol of a dynamic navigation system to perform all surgeries. Bone height, implant primary stability, and visual analogue scale (VAS) at 1-day and 7-day follow-up for postoperative discomfort were assessed in both groups. Time of antrostomy with sinus membrane elevation and area of antrostomy was measured in the lateral window group.
Results: Sixteen sinus augmentations in fifteen patients were done uneventfully. Twelve sinuses were augmented by the lateral window approach and four sinuses were augmented by the transcrestal approach. No intra- and postoperative complications have occurred. In the transcrestal and lateral window group, the mean initial bone height was 8.0 and 3.4 mm (p < 0.01), augmented bone height was 4.1 and 11.7 mm (p < 0.01), insertion torque was 27.5 and 26.3 Ncm (p=0.67) respectively, and the mean VAS score was 3.1 and 4.1 (p=0.35) at 1-day follow-up, 1.2 and 1.3 (p=0.82) at 7-day follow-up respectively. The mean time of antrostomy with membrane elevation was 849 seconds and the area of the antrostomy was 48.2 mm2 in the lateral window group. VAS score and implant primary stability between the two groups were no significant differences. The lateral window group augmented bone height significantly more than the transcrestal group. Under dynamic navigation, the surgeon could precisely prepare osteotomy and carefully perforate sinus floor by transcrestal approach and efficiently bypass the anatomical limit without complications by lateral approach in real-time.
Conclusions: The dynamic navigation system was a practical tool to guide antrostomy and implant osteotomy by transcrestal and lateral window approach in real-time. The results demonstrated the navigation-assisted sinus floor elevation was accurate, efficient, and less painful.
Lead Author's Contributions to the Research Project. : The Lead Author was responsible for the data collection, performing clinical procedures, the data analysis and the composition of the abstract.
