J Dent Rehabil Appl Sci.  2018 Jun;34(2):104-115. 10.14368/jdras.2018.34.2.104.

Comparative study on quality of scanned images from varying materials and surface conditions of standardized model for dental scanner evaluation

• Park JH
• Seol JH
• Lee JJ
• Lee SP
• Lim YJ

• KMID: 2422652
• DOI: http://doi.org/10.14368/jdras.2018.34.2.104

Abstract

PURPOSE
The purpose of this study is to evaluate the image acquisition ability of intraoral scanners by analyzing the comprehensiveness of scanned images from standardized model, and to identify problems of the model.
MATERIALS AND METHODS
Cast models and 3D-printed models were prepared according to international standards set by ISO12836 and ANSI/ADA no. 132, which were then scanned by model scanner and two different intraoral scanners (TRIOS3 and CS3500). The image acquisition performance of the scanners was classified into three grades, and the study was repeated with varying surface conditions of the models.
RESULTS
Model scanner produced the most accurate images in all models. Meanwhile, CS3500 showed good image reproducibility for angled structures and TRIOS3 showed good image reproducibility for rounded structures. As for model ingredients, improved plaster model best reproduced scan images regardless of the type of scanner used. When limited to 3D-printed model, powdered surface condition resulted in higher image quality.
CONCLUSION
When scanning structures beyond FOV (field of view) in standardized models (following ISO12836 and ANSI/ADA 132), lack of reference points to help distinguish different faces confuses the scanning and matching process, resulting in inaccurate display of images. These results imply the need to develop a new standard model not confined to simple pattern repetition and symmetric structure.

Keyword

international standard model; intraoral scanner; model scanner; accuracy; digital impression

Figure

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  Fig. 1 The standard model image made with the 3D printer. (A) Crown model of ANSI/ADA 132, (B) inlay model of ANSI/ADA 132, (C) inlay model of ISO 12836 and (D) crown/bridge model of ISO 12836.

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  Fig. 2 The standard model image made with the improved stone. (A) Crown model of ANSI/ADA 132, (B) inlay model of ANSI/ADA 132, (C) inlay model of ISO 12836 and (D) crown/bridge model of ISO 12836.

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  Fig. 3 A schematic diagram of the image acquisition of various scanners according to materials and surface conditions of the standard models.

Reference

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