Korean J Orthod.  2014 Mar;44(2):69-76. 10.4041/kjod.2014.44.2.69.

Accuracy and precision of polyurethane dental arch models fabricated using a three-dimensional subtractive rapid prototyping method with an intraoral scanning technique

• Kim JH
• Kim KB
• Kim WC
• Kim JH
• Kim HY

• KMID: 2273429
• DOI: http://doi.org/10.4041/kjod.2014.44.2.69

Abstract

OBJECTIVE
This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models.
METHODS
Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of inter-examiner and inter-method variability.
RESULTS
The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement.
CONCLUSIONS
The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

Keyword

Three-dimensional subtractive rapid prototyping; Intraoral scanning; Accuracy; Precision

MeSH Terms

Dental Arch*
Dental Models
Polyurethanes*
Polyurethanes

Figure

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  Figure 1 Reference points and linear measurements on the upper full arch model. A, Upper view; B, oblique view from the right side; C, oblique view from left side. See Table 1 for the definition of the reference points.

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  Figure 2 Bland-Altman plot. A, Repeatability, intra-examiner variability; B, reproducibility, inter-examiner variability; C, reproducibility, inter-method variability. '95% limit of agreement (LoA)' represents mean difference ± 1.96 standard deviation.

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