Influence of Preparation Height on Digital Impression Trueness: A Comparative Study of 2 Intraoral Scanners

Abstract

Background: This study aims to evaluate the effect of crown preparation height on the trueness of intraoral scanners (IOS) by comparing 2 different scanners at varying preparation heights.

Methods: A typodont model was prepared with a chamfer finish line at 2 different crown heights (7 mm and 5 mm). A laboratory scanner (E1, 3Shape, Copenhagen, Denmark) was used to obtain a reference scan. Intraoral scanners, Trios 3 (3Shape, Copenhagen, Denmark) and iTero Element 5D Plus (Align Technologies, San Jose, USA), were used for digital impressions. Ten scans were taken for each preparation height per scanner, resulting in a total of 40 scans. The trueness was assessed using Geomagic Control X software by calculating root mean square (RMS) error values between IOS scans and the reference model. Statistical analysis was performed using IBM SPSS v29. An independent sample t-test was applied (α=0.05).

Results: The iTero scanner exhibited significantly lower RMS values (0.040 ± 0.005 mm) compared to the Trios 3 scanner (0.049 ± 0.006 mm, P < .001), indicating higher overall trueness. The Trios 3 scanner showed a significant difference in trueness between 5 mm (0.051 ± 0.005 mm) and 7 mm (0.046 ± 0.006 mm) preparations (P=.043), demonstrating improved trueness with greater preparation height. In contrast, the iTero scanner maintained consistent trueness across both preparation heights (P=.451).

Conclusion: The trueness varies depending on the intraoral scanner used. Crown height is a factor that affects trueness depending on the scanner.

Cite this article as: Özden YE, Yılmaz Z, Özkurt Kayahan Z, Kazazoğlu E. Influence of preparation height on digital impression trueness: a comparative study of 2 intraoral scanners. Essent Dent. 2025, 4, 0030, doi:10.5152/EssentDent.2025.25030.