Abstract
PURPOSE: This study aimed to evaluate the effect of implant angulation on the trueness and precision of intraoral scanning (IOS) using different prefabricated auxiliary device (PAD) designs and to compare the results with two photogrammetry (PG) systems. MATERIALS AND METHODS: Three master models with 5 implants were fabricated to simulate edentulous maxillary arches, featuring implant configurations including all implants parallel, one implant angulated 25° mesially, and one implant angulated 25° distally. Five digital impression techniques were evaluated: IOS (Cerec Primescan) without PADs (IOS), with crown-shaped PADs (IOS-C), with laterally extended PADs (IOS-LE), and two PG systems (ICam4D G3: PG-I, OxoCore: PG-O). Reference data were acquired using a laboratory scanner, and implant center coordinates in both reference and test datasets were determined in Geomagic Control X for deviation calculations. Linear deviations (LD), angular deviations (AD), and root mean squared error (RMS) values were calculated to assess trueness and precision, and were statistically analyzed. RESULTS: Significant accuracy differences were observed between the PG systems, with PG-I exhibiting the lowest RMS values (18 ± 3.27 μm) across all models and maintaining deviations within clinically acceptable thresholds (P<0.01). IOS-LE showed significantly lower RMS and AD values compared to IOS and IOS-C. Implant angulation negatively affected the trueness of IOS, IOS-C, and PG-O, particularly with distal angulation (P<0.01), while PG-I and IOS-LE remained unaffected (P > 0.05). Implant angulation did not significantly affect precision (P = 0.328). CONCLUSION: PG-I demonstrated the highest accuracy. Implant angulation compromised IOS trueness, but laterally extended PADs improved accuracy, making IOS comparable to PG systems. CLINICAL SIGNIFICANCE: These findings indicate that, even in angulated full‑arch implant cases, photogrammetry (PG‑I) and IOS with laterally extended PADs provide clinically acceptable accuracy and may serve as reliable digital impression techniques in practice.