Accuracy (Trueness and Precision) of the Calibrated Intraoral Scan Protocol: An In Vitro Comparison of Three Scan Calibrator Designs In an Edentulous Implant Model

Abstract

Objectives

To introduce a universal scan calibrator (SC) and to evaluate its accuracy in the calibrated intraoral scan protocol (CISP) by comparison with two previously published SCs.

Materials and Methods

Three SCs were evaluated on an edentulous implant model containing six scan bodies (SBs) positioned at the screw-retained abutment (SRA) level: (1) a universal SC with a C-shaped window (SC-CW), (2) an SC covering only the alveolar ridge (SC-R), and (3) an SC limited to the palatal region (SC-P). Each SC was attached to the model and scanned 10 times using an intraoral scanner (IOS). The intraoral scans were subsequently corrected using the corresponding desktop scans of the SCs as reference data. A desktop scan of the model served as the reference. The test scans were superimposed onto the reference scan by: (1) using all SBs to evaluate the overall fit, and (2) using the first and second SBs to simulate the virtual Sheffield test. Linear and angular deviations of SRAs were measured using Python scripts.

Results

When aligned by all SBs, all three groups exhibited significant improvements in trueness and linear precision following correction. In the virtual Sheffield test, no statistically significant differences were observed in post-correction trueness or angular precision at the ending SRA6. All three groups achieved clinically acceptable trueness and precision values following correction.

Conclusions

All three SCs yielded clinically acceptable impressions after correction under in vitro conditions. The novel SC represents a promising approach for CISP; however, further in vivo clinical evidence is required.