J Adv Prosthodont.  2014 Aug;6(4):266-271. 10.4047/jap.2014.6.4.266.

Bond and fracture strength of metal-ceramic restorations formed by selective laser sintering

• Bae EJ
• Kim JH
• Kim WC
• Kim HY

• KMID: 1974845
• DOI: http://doi.org/10.4047/jap.2014.6.4.266

Abstract

PURPOSE
The purpose of this study was to compare the fracture strength of the metal and the bond strength in metal-ceramic restorations produced by selective laser sintering (SLS) and by conventional casting (CAST).
MATERIALS AND METHODS
Non-precious alloy (StarLoy C, DeguDent, Hanau, Germany) was used in CAST group and metal powder (SP2, EOS GmbH, Munich, Germany) in SLS group. Metal specimens in the form of sheets (25.0 x 3.0 x 0.5 mm) were produced in accordance with ISO 9693:1999 standards (n=30). To measure the bond strength, ceramic was fired on a metal specimen and then three-point bending test was performed. In addition, the metal fracture strength was measured by continuing the application of the load. The values were statistically analyzed by performing independent t-tests (alpha=0.05).
RESULTS
The mean bond strength of the SLS group (50.60 MPa) was higher than that of the CAST group (46.29 MPa), but there was no statistically significant difference. The metal fracture strength of the SLS group (1087.2 MPa) was lower than that of the CAST group (2399.1 MPa), and this difference was statistically significant.
CONCLUSION
In conclusion the balling phenomenon and the gap formation of the SLS process may increase the metal-ceramic bond strength.

Keyword

Selective laser sintering; Metal-ceramic restoration; Bond strength; Fracture strength; Balling phenomenon

MeSH Terms

Alloys
Ceramics
Fires
Alloys
Ceramics

Figure

• 

  Fig. 1 SEM images of SLS specimens magnified at ×33 (A), ×100 (B), and ×500 (C) and of CAST specimens at ×33 (D) and ×100 (E). The black arrow was the spacing between the layers (about 10-20 µm).

• 

  Fig. 2 SEM images of an SLS specimen magnified at ×650 (A) and ×3,000 (B).

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