Accuracy of intraoral scanners and photogrammetry for full-arch implant-supported rehabilitations: an in vitro study

Abstract

Objectives: This in vitro study aimed to compare the accuracy of intraoral scanning and photogrammetry-based acquisition methods for full-arch implant-supported rehabilitations involving four and six implants. Methods: An acrylic edentulous mandible was used to simulate the clinical setting. Implant positions were acquired 20 times per condition using five intraoral scanners with polyetheretherketone (PEEK) and titanium scan bodies, one photogrammetry-capable intraoral scanner, and three dedicated photogrammetry systems. Implant replicas were generated and analyzed using reverse-engineering software. Linear (µm) and angular (°) discrepancies were calculated to assess trueness and precision. Linear mixed-effects models were applied separately for linear and angular discrepancies, with impression method, implant configuration, and their interaction as fixed effects. Results: Mean linear trueness discrepancies ranged from 35.76 to 403.51 µm. Impression method significantly influenced linear and angular discrepancies (p < 0.001). Implant configuration had a significant effect, with higher discrepancies observed with six implants. No significant interaction was detected between impression method and implant configuration. Most photogrammetry-based systems showed lower discrepancies than the intraoral scanners, although substantial device-specific variability was observed. No consistent trend favoring PEEK or titanium scan bodies was observed. Conclusions: Impression method and implant configuration significantly influenced impression accuracy. Photogrammetry-based systems generally showed lower discrepancies, although device-specific performance should be considered when interpreting accuracy. Six-implant configurations, which involved a greater scanning span, were associated with lower accuracy. Further clinical studies are needed to determine whether these differences are clinically relevant.