Impact of Level of Guidance on the Accuracy of Static Computer‐Assisted Implant Surgery (s‐CAIS): An In Vitro Study

ABSTRACT Background Accurate implant placement is essential for predictable functional and esthetic outcomes. Although static computer‐assisted implant surgery (s‐CAIS) is more accurate than freehand placement, the effects of increasing guidance within partially guided workflows and on adjacent‐implant relationships remain unclear. This in vitro study compared accuracy across six workflows and assessed inter‐implant parallelism and vertical platform discrepancy. Methods Twenty mandibular models were used per workflow, with two implants placed in each model (40 implants per workflow). Workflows comprised non‐guided placement, universal and system‐specific pilot‐drill guidance, intermediate‐drill guidance, and two fully guided systems. Planned positions were compared with postoperative STL datasets. Outcomes included 3D platform and apical deviations, angular and directional deviations, precision, and adjacent‐implant vertical and angular discrepancies. Two‐way ANOVA and a linear mixed model were applied. Results Workflows differed significantly across parameters. Fully guided systems showed the lowest 3D and angular deviations and highest precision, with deviations as low as 0.23 ± 0.10 mm and 1.25° ± 0.61°. Greater guidance was associated with reduced linear and angular deviation. Vertical platform discrepancy was lowest with fully guided workflows (0.05–0.06 mm), followed by partially guided workflows (0.08–0.09 mm) and freehand placement (0.15 mm). Conversely, fully guided workflows showed numerically greater inter‐implant angular discrepancy (1.37°–1.69°) than partially guided workflows (1.00°–1.13°). Conclusions Accuracy varied by guidance level. Fully guided workflows provided the highest trueness and precision and most consistent vertical platform positioning. Greater plan‐to‐implant accuracy was not accompanied by improved inter‐implant parallelism, indicating that these outcomes should be evaluated separately.