A novel Snap-FIT implant surgical guide design: a case report

To clinically evaluate the precision of a novel tooth-supported snap-FIT surgical guide (SF), inspired by the removable dentures clasp principle. Two patients with a single missing tooth underwent CBCT and optical scans, that were superimposed for implant virtual planning (BlueSkyBio, USA). A novel SF implant surgical guide for each case was designed and 3D printed (offset from the surface 0.07 mm, material thickness 2.3 mm, selective undercuts allowed). Under local anesthesia, a full-thickness flap was elevated and SF positioned. Drill sequence was partially guided, with profiling, taping of implant bed, and implant placement done free-hand. One narrow (NC) and one regular diameter (RC) bone-level implants were placed (Straumann, CH). Further, 5-0 non-resorbable sutures were used for wound closure. The duration of surgery was 24 min and 27 min, respectively. Healing was uneventful in both cases. After 4 months, implants were uncovered and implant position recorded with the intraoral scanner. Source files and the scanned data were aligned (error: 0.05 mm/0.02 mm, GOM inspect, Germany). A novel implant accuracy evaluation method was developed. The apical and neck point of the implant was determined as an intersection point of a plane and cylinder, generated from the scan body (Gaussian best-fit). Implant placement error at the implant neck was 0.67 mm/0.3 mm, at the apex 1.02 mm/0.32 mm and the angle deviation 3.28°/3.33° for NC and RC implant, respectively. The novel SF surgical guide is feasible with a simple modification of classical guide design, without requiring additional materials, devices, or procedures. It demonstrates high implant placement accuracy, similar to the fully guided protocol.