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Updated: Jul 11, 2026
Accuracy in Dental Medicine, A New Way to Measure Trueness and Precision
Published on: April 29, 2014
Influence of enamel and dentin roughness on intraoral scanner accuracy
Guilherme F Moura1, Gustavo Mendonça2, Fabio A P Rizzante3
1Assistant Professor, Department of Reconstructive and Rehabilitation Science, James B. Edwards College of Dental Medicine, Medical University of South Carolina, Charleston, SC.
Statement Of Problem:
The accuracy of intraoral scanning is crucial for the long-term survival of indirect restorations. It remains unclear if preparation protocols, surface characteristics, and humidity play a role in the quality of an intraoral scan.
Purpose:
The purpose of this in vitro study was to assess the impact of margin preparation on both dentin and enamel using different finishing protocols. These assessments were conducted on specimens stored in both dry and wet environments, with a specific focus on evaluating their influence on the accuracy of intraoral scans.
Material And Methods:
Six maxillary canines were prepared using three different sequences. In the first sequence, a coarse diamond rotary instrument (DC) was used. In the second, DC was followed by a fine grit diamond rotary instrument (DCDF). In the third, the DC was followed by a tungsten carbide rotary instrument. Margins were scanned 10 times using an intraoral scanner (TRIOS 3; 3Shape A/S) compared to a laboratory scanner (D2000; 3Shape A/S). Accuracy was determined by measuring precision and trueness (Geomagic Control; Hexagon). To assess the impact of 3-dimensional (3D) topography on accuracy, roughness was measured using a laser microscope (Lext OLS 4000; Olympus). The data were analyzed using the Levene test, followed by a 3-way ANOVA with Bonferroni post hoc testing to assess the effects and interactions of surface finish, environment, and tissue on the outcomes (α=.05).
Results:
Improved precision was observed in enamel (15.7 µm) compared to dentin (24.3 µm) specimens (P<.001). Furthermore, the environment had a significant impact on accuracy (P<.001). Higher precision and trueness (P<.001) were observed for dentin in dry (18.3 µm) compared to wet (37.3 µm) conditions. The use of fine grit diamond rotary instruments improved precision and trueness for dry dentin (DC/DCDF P=.017; DC/DCCF P=.005; DCDF/DCCF P>.999), while no difference was detected for dry enamel (DC/DCDF P=.966; DC/DCCF P=.822; DCDF/DCCF P=.519). The use of a second finishing rotary instrument decreased Sa (µm) for dentin (DC/DCDF/DCCF) (7.11/5.63/4.53), whereas enamel values were similar (7.94/8.53/9.97).
Conclusions:
Surface roughness, tooth substrate, and scanning environment (or humidity conditions) were found to influence the accuracy of intraoral scans.
