Objectives <p>To quantify the trueness of fully guided static computer-assisted implant surgery (s-CAIS) for immediate implant placement in premolar and molar sites, and to explore whether implant and workflow parameters are associated with angular deviation.</p> Materials and methods <p>In this observational analysis of a cohort derived from a previously randomized clinical trial, 49 implants were placed immediately after extraction using a fully guided s-CAIS workflow. Preoperative planning data were compared with a 3-month postoperative cone-beam computed tomography (CBCT) scan using a manufacturer-developed analysis module. Trueness was assessed as 3D, vertical, and lateral deviation at the implant platform, as well as angular deviation. Between group comparisons were interpreted as exploratory.</p> Results <p>In 49 implants (25 maxilla, 24 mandible; 34 molars, 15 premolars), mean (standard deviation, SD) platform deviations were 0.92 (0.40) mm for 3D deviation, − 0.26 (0.63) mm for vertical deviation (negative indicates shallower placement), and 0.66 (0.33) mm for lateral deviation. Mean (SD) angular deviation was 3.77 (2.28) degrees. In exploratory analyses, angular deviation differed between implant length groups (<i>p</i> = 0.010). Categories with a single implant in sleeve height (H2) and drill length (16&#xa0;mm) were reported descriptively only.</p> Conclusions <p>In this observational cohort, fully guided s-CAIS yielded platform-based trueness and angular deviation values for immediate implant placement in premolar and molar sites that were within ranges reported in the guided surgery literature. Findings on factors associated with angular deviation should be interpreted as exploratory and require confirmation in further studies.</p> Clinical relevance <p>Provides in vivo trueness estimates for fully guided implant placement performed immediately after extraction in premolar and molar sites.</p>