A Prosthetically Coupled Tripod Fixation Concept for Edentulous Surgical Guides: A Three-Case Proof-of-Concept Study

Background: Stabilization of surgical guides in fully edentulous patients remains a clinical challenge due to mucosal resilience and potential micromovement, even when fixation pins are used. Guide instability may affect drilling accuracy and overall workflow predictability. This proof-of-concept case series describes a stabilization approach based on pre-placed tripod reference implants with multi-unit coupling, designed to create a mechanically defined prosthetic docking platform for fully guided implant surgery. Methods: Three fully edentulous patients requiring implant-supported rehabilitation were treated using a two-stage protocol. Three temporary reference implants were inserted in a tripod configuration 7-10 days prior to definitive surgery. Multi-unit abutments were mounted on the reference implants, and intraoral scanning was performed to design a surgical guide indexed to the prosthetic interfaces. During implant placement, the guide was screw-retained to the reference implants via the multi-unit connections. Postoperative implant positions were evaluated radiographically by superimposing postoperative datasets onto the preoperative planning model. Intraoperative guide stability, surgical events, and early postoperative outcomes were recorded. Results: Stable guide fixation was achieved in all three cases without detectable intraoperative displacement. Implant placement was completed as planned in each patient, and removal of the temporary reference implants was uneventful. No intraoperative or early postoperative complications were observed. Mean coronal, apical, and angular deviations between planned and achieved implant positions were 0.70 ± 0.16 mm, 0.39 ± 0.13 mm, and 3.30 ± 0.59°, respectively. These preliminary findings, derived from four treated arches, were comparable to ranges reported in selected studies on fully guided implant surgery; however, no direct statistical comparison with previously published datasets was performed. Conclusions: Within the limitations of this proof-of-concept case series, temporary reference implants arranged in a tripod configuration provided a stable and reproducible prosthetic indexing platform for guided implant surgery in fully edentulous patients. Further prospective studies involving larger patient cohorts and controlled comparative designs with conventional mucosa-supported or fixation-pin-supported surgical guides are required to evaluate the reproducibility, clinical performance, and long-term applicability of this stabilization concept.