Full-Arch Trans-Sinus Implant Placement Using a Stackable Surgical Guide With Digitally Planned Antrostomy: A Case Report

Introduction: This report presents a fully digital workflow for maxillary full-arch rehabilitation that integrates trans-sinus implant placement into a stackable guided surgery system. The technique incorporates a digitally planned antrostomy guide to enable controlled lateral sinus access. Methods: A sequential stackable guide protocol was developed, including key, base, drive, and prosthetic templates, together with a custom antrostomy guide. The system was designed to translate the virtual plan into precise implant positioning and reproducible lateral window preparation for trans-sinus implant placement. Results: The digital workflow enabled accurate localization of the sinus window and guided insertion of a tilted trans-sinus implant along the planned trajectory. The combined guide system provided controlled sinus access and stable implant placement suitable for immediate loading. Conclusion: Integrating a digitally planned antrostomy guide within a stackable surgical system enhances precision in full-arch rehabilitations requiring trans-sinus implants. This digital technique expands the applicability of guided surgery to challenging posterior maxillary scenarios.