A Novel Eccentric Surgical Guide Strategy for Immediate Implant Placement: An In Vitro Study.

This study aims to evaluate the implantation accuracy of a novel eccentric surgical guide strategy for immediate implant placement (IIP). Two hundred CBCTs were used to measure anatomical parameters, and the obtained data were used to create an anatomical extra-oral model for IIP. Eccentric guides are specialized guides that position the drills or implant eccentrically toward the high-density side. Thirty implants were placed into fifteen anatomical models utilizing three different computer-assisted static implant surgery (sCAIS) protocols: the conventional, the one-step, and the step-by-step methods. Postoperative CBCTs were superimposed on the preoperative virtual placement plan to assess 3D and 2D deviations at the implant entry and apex point. The average angle between the model's inclined plane and the implant's central axis was 18.3°, ranging from 10° to 39°. The one-step eccentric method (Group B) had the smallest 3D deviation at the entry point (mean = 0.41 ± 0.14 mm), apex (mean = 0.68 ± 0.20 mm), and angular deviation (mean = 1.74 ± 0.68°). The 2D deviation analysis showed Group B had the lowest labial deviations at the entry (mean = 0.37 ± 0.16 mm) and apex (mean = 0.36 ± 0.29 mm). The step-by-step eccentric method (Group C) resulted in a considerable reduction in labial deviation at the apex (mean = 0.35 ± 0.39 mm). The novel eccentric surgical guide strategy increased implantation accuracy in IIP, particularly by lowering labio-palatal discrepancies. Implant position can be affected by the anatomical structure of the tooth extraction socket. Therefore, it is critical to find a novel eccentric surgical guide strategy to address labial deflection during implant site preparation for IIP.