Accuracy of Complete-Arch Implant Scans Using Non Calibrated Splinting Scanbodies

Complete-arch implant scanning can be challenging because errors during image acquisition and stitching may accumulate across the arch. Non-calibrated splinting techniques have been introduced to stabilize implant scan bodies and improve the reliability of complete-arch digital implant impressions without requiring scanner-specific calibration.

This randomized crossover clinical study will evaluate and compare two non-calibrated splinting systems, IoConnect and Scan Pro, for complete-arch implant scanning in completely edentulous patients rehabilitated with implant-supported prostheses.

Eligible participants will have a completely edentulous maxilla or mandible and four well-integrated implants connected to multiunit abutments. Patients with fewer or more than four implants, failed implants, active peri-implant infection or suppuration, or limited mouth opening will be excluded.

A verified conventional splinted implant impression will first be obtained to establish a reference cast. Open-tray impression copings will be splinted intraorally using chemically polymerized acrylic resin, and the definitive impression will be made using polyvinyl siloxane impression material. A verification jig will be fabricated and used to confirm the passive fit of the reference cast. The verified reference cast will subsequently be digitized using a calibrated laboratory scanner to generate the reference digital model.

Each participant will undergo both digital scanning protocols. The order of the two protocols will be randomized using a computer-generated randomization sequence to minimize potential order and operator learning effects.

For the Scan Pro workflow, implant scan bodies will be connected to the multiunit abutments, and adjustable arms will be added to provide optical splinting. The complete-arch implant scan will then be obtained using an intraoral scanner.

For the IoConnect workflow, peri-implant soft-tissue anatomy will first be captured using healing abutments. Following removal of the healing abutments, horizontal IoConnect scan bodies will be attached to the multiunit abutments and a complete-arch implant scan will be obtained using the same intraoral scanner. The soft-tissue scan and optical marker scan will subsequently be merged using the dedicated software to generate the final digital implant impression.

To standardize the datasets and minimize the influence of differences in scan-body geometry and digital mesh reconstruction, the scan bodies captured during scanning will be replaced with the corresponding manufacturer-provided CAD library files. An identical implant-supported bar framework will then be virtually designed for each dataset. The resulting STL files will be analyzed using three-dimensional reverse-engineering software.

Accuracy will be assessed by comparing the experimental datasets with the reference digital model. Linear discrepancy will be determined as the three-dimensional Euclidean distance between corresponding implant measurement points, while angular discrepancy will be determined as the angle between corresponding implant longitudinal axes. Measurements will be obtained for all four implants in each dataset, and mean linear and angular discrepancies will be calculated.

Chairside time associated with the digital scanning procedures will also be evaluated. Statistical analysis will include assessment of data normality and comparison of the paired linear and angular deviations between the two scanning protocols using a paired t-test, with statistical significance set at α = .05.