Influence of Implant Angulation on the Accuracy of Complete Arch Digital Scans with Intraoral Photogrammetry

To evaluate the influence of implant angulation on the trueness, and precision of complete arch implant digital scans acquired using an intraoral photogrammetry system.

Two edentulous mandibular models with six implants each were fabricated and assigned to two groups based on implant angulation: parallel implants and posterior angulated implants. In the angulated group, posterior implants were angled (<30° relative to the reference axis), resulting in interimplant angulations of up to approximately 45° due to their spatial relationships. Each group was scanned 20 times (n=40) using an intraoral scanner incorporating intraoral photogrammetry technology under standardized ambient lighting conditions (1000 lux). Linear and angular deviations were calculated by comparing the test scans with reference datasets obtained using a calibrated laboratory scanner. The Shapiro-Wilk, Mann-Whitney U, and Levene tests were used to analyze differences in trueness and precision between groups (α=.05).

For trueness, the parallel group showed significantly lower linear deviations (median 0.066 mm; IQR 0.063-0.071) than the angulated group (median 0.159 mm; IQR 0.155-0.162) (P < 0.001). For angular deviations, the angulated group showed lower values (median 0.353°; IQR 0.347-0.380) than the parallel group (median 0.457°; IQR 0.450-0.467) (P < 0.001). No statistically significant differences in precision were found for either linear (P=.664) or angular (P=.070) measurements.

Implant angulation significantly influenced trueness, while precision remained unaffected. Higher angulation resulted in increased linear deviations, although angular deviations may not be clinically significant.