J Adv Prosthodont.  2018 Oct;10(5):354-360. 10.4047/jap.2018.10.5.354.

Accuracy of provisional crowns made using stereolithography apparatus and subtractive technique

• Kang SY
• Park JH
• Kim JH
• Kim WC

• KMID: 2422871
• DOI: http://doi.org/10.4047/jap.2018.10.5.354

Abstract

PURPOSE
To compare and analyze trueness and precision of provisional crowns made using stereolithography apparatus and subtractive technology.
MATERIALS AND METHODS
Digital impressions were made using a master model and an intraoral scanner and the crowns were designed with CAD software; in total, 22 crowns were produced. After superimposing CAD design data and scan data using a 3D program, quantitative and qualitative data were obtained for analysis of trueness and precision. Statistical analysis was performed using normality test combined with Levene test for equal variance analysis and independent sample t-test. Type 1 error was set at 0.05.
RESULTS
Trueness for the outer and inner surfaces of the SLA crown (SLAC) were 49.6±9.3 µm and 22.5±5.1 µm, respectively, and those of the subtractive crown (SUBC) were 31.8±7.5 µm and 14.6±1.2 µm, respectively. Precision values for the outer and inner surfaces of the SLAC were 18.7±6.2 µm and 26.9±8.5 µm, and those of the SUBC were 25.4±3.1 µm and 13.8±0.6 µm, respectively. Trueness values for the outer and inner surfaces of the SLAC and SUBC showed statistically significant differences (P < .001). Precision for the inner surface showed significance (P < .03), whereas that for the outer surface showed no significance (P < .58).
CONCLUSION
The study demonstrates that provisional crowns produced by subtractive technology are superior to crowns fabricated by stereolithography in terms of accuracy.

Keyword

Stereolithography apparatus; Subtractive technology; Provisional crown; CAD/CAM system

MeSH Terms

Crowns*

Figure

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  Fig. 1 Trueness of outer surface using color difference map. Green represents good fit, red represents positive error, and blue represents negative error. (A) Stereolithography apparatus Crown, (B) Subtractive crown.

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  Fig. 2 Trueness of the inner surface using color difference map. Green represents good fit, red represents positive error, and blue represents negative error. (A) Stereolithography apparatus Crown, (B) Subtractive crown.

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  Fig. 3 Precision of the outer surface using color difference map. Green represent good fit, red represents positive error, and blue represents negative error. (A) Stereolithography apparatus crown, (B) Subtractive crown.

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  Fig. 4 Precision of the inner surface using color difference map. Green represents good fit, red represents positive error, and blue represents negative error. (A) Stereolithography apparatus crown, (B) Subtractive crown.

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  Fig. 5 Digital microscopy images of the crowns made through stereolithography and subtractive techniques. (A) Stereolithography apparatus crown, (B) Subtractive crown.

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  Fig. 6 Digital microscopy images of the provisional crowns made by means of: (A) stereolithography apparatus surface, (B) subtractive crown surface.

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