Related Experiment Video
Updated: Jun 14, 2026
Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision
Published on: April 29, 2014
Accuracy of full-arch digital implant impression and bite registration: effect of different reference object
Vygandas Rutkūnas1, Andrius Kubilius2, Mykolas Akulauskas3
1Professor, Department of Prosthodontics, Institute of Odontology, Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
Objectives:
This in vitro study evaluated the accuracy of digital impressions for full-arch implantsupported restorations by assessing scan body (SB) positional accuracy and inter-arch registration under different intraoral scanners (IOS) and scan protocol conditions.
Methods:
Two IOSs (Medit i700 and Trios 5) were evaluated across multiple protocols. In Part A, SB trueness and precision were investigated using three inter-implant distances (1-2, 1-3, 1-4) and angulations across five groups (n = 10 each), with and without reference objects (ROs) on an edentulous maxillary model. In Part B, inter-arch distance accuracy was evaluated with the help of four sphere pairs used in the same upper edentulous arch with implants and a dentated mandibular model in an articulator using six scanning protocols, including one- and two-step bite registration. Trueness and precision were analyzed using linear mixed-effects models for each data type.
Results:
In Part A, Medit i700 with ROs (A-M700-RO) showed the highest trueness and precision in both linear and angular SB measurements. RO use significantly improved performance, particularly for Trios 5. Angular deviation was lowest in A-M700-RO, especially in distal segments (mean difference -0.24°, p < 0.05). In Part B, Trios 5 with a two-step RO bite registration (B-T5-RO-1) had the highest inter-arch accuracy, especially in molar regions. Accuracy in this group was significantly higher than all other groups (p < 0.01).
Conclusions:
Digital impression accuracy is influenced by both the scanner type and scanning protocol. Additional reference objects improved the accuracy of distance measurements but did not significantly affect measurements of angulation. Medit i700 outperforms in SB accuracy, while Trios 5 excels in inter-arch registration when combined with ROs and a two-step protocol.
Clinical Significance:
Additional reference objects may improve the digital implant impressions' distance accuracy, although they do not significantly affect angulation outcomes.
