J Adv Prosthodont.  2018 Aug;10(4):321-327. 10.4047/jap.2018.10.4.321.

A study on the machining accuracy of dental digital method focusing on dental inlay

• Bae EJ
• Jeong ID
• Kim WC
• Kim JH

• KMID: 2418639
• DOI: http://doi.org/10.4047/jap.2018.10.4.321

Abstract

PURPOSE
The purpose of this study was to compare the cutting method and the lamination method to investigate whether the CAD data of the proposed inlay shape are machined correctly.
MATERIALS AND METHODS
The Mesial-Occlusal shape of the inlay was modeled by changing the stereolithography (STL). Each group used SLS (metal powder) or SLA (photocurable resin) in the additive method, and wax or zirconia in the subtractive method (n=10 per group, total n=40). Three-dimensional (3D) analysis program (Geomagic Control X inspection software; 3D systems) was used for the alignment and analysis. The root mean square (RMS) in the 2D plane state was measured within 50 µm radius of eight comparison measuring points (CMP). Differences were analyzed using one-way analysis of variance and post-hoc Tukey's test were used (α=.05).
RESULTS
There was a significant difference in RMS only in SLA and SLS of 2D section (P < .05). In CMP mean, CMP 4 (−5.3±46.7 µm) had a value closest to 0, while CMP 6 (20.1±42.4 µm) and CMP 1 (−89.2±61.4 µm) had the greatest positive value and the greatest negative value, respectively.
CONCLUSION
Since the errors obtained from the study do not exceed the clinically acceptable values, the lamination method and the cutting method can be used clinically.

Keyword

Additive manufacturing; Subtractive manufacturing; Three-dimensional analysis; Inlay

MeSH Terms

Inlays*
Methods*
Radius

Figure

• 

  Fig. 1 Schematic of the inlay geometry three-dimensional modeling.

• 

  Fig. 2 Experimental procedure for 3D accuracy analysis. (A) Virtual reference data. Inlay shape of the Mesial-Occlusal cavity using CAD software. (B) The manufactured specimens were scanned through a dental scanner. (C) Analyze of align the CAD data and the scanned data. And eight comparison measuring points positioning. (D) 2D plane for cross section analysis.

• 

  Fig. 3 Error values of virtual reference data and scan data measured in a two-dimensional cross section. Orange box; Maximum error value of scan data. Blue box; Minimum error value of scan data. (A) SLA (photocurable resin), (B) SLS (metal powder), (C) WAX (wax), (D) ZIR (zirconia).

• 

  Fig. 4 Box plot for mean values of comparison measuring points.

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