A Comparison between Shear Bond Strength of VMK Master Porcelain with Three Base-metal Alloys (Ni-cr-T3, VeraBond, Super Cast) and One Noble Alloy (X-33) in Metal-ceramic Restorations.
BACKGROUND
The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain.


METHODS
Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble alloy (X-33) were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-by-two by adopting Tukey test.


RESULTS
The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys (94 MPa or 330 N). Super Cast alloy had the second greatest shear bond strength (80. 87Mpa or 283.87 N). Both VeraBond (69.66 MPa or 245 N) and x-33 alloys (66.53 MPa or 234 N) took the third place.


CONCLUSIONS
Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metal-ceramic restorations.
Dept. of Prosthodontics, School of Dentistry, Ahwaz University of Medical Sciences, Ahwaz, Iran.
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A
Ahmadzadeh
Resident of Prosthodontics, School of Dentistry, Ahwaz University of Medical Sciences, Ahwaz, Iran.
A
A
Neshati
Resident of Prosthodontics, School of Dentistry, Ahwaz University of Medical Sciences, Ahwaz, Iran.
N
N
Mousavi
Resident of Prosthodontics, School of Dentistry, Ahwaz University of Medical Sciences, Ahwaz, Iran.
S
S
Epakchi
Resident of Operative Dentistry, School of Dentistry, Ahwaz University of Medical Sciences, Ahwaz, Iran.
F
F
Dabaghi Tabriz
Prosthodontic Specialist.
Ah
A
Sarbazi
Base-metal Alloy; Noble Alloy; Porcelain; Shear bond