Chipping of veneering ceramic is a frequent problem with all-ceramic restorations. The failure rate is reported to be up to 30%. Aim of the study was to test a veneering ceramic, which was developed in order to achieve improved bonding to the framework ceramic. Thus, failure due to chipping should be reduced.
Method:
Samples were made with cubes of investment material (aus IPS Empress Vest Speed, Ivoclar, Schaan, LI). An opening for ceramic cylinders was CNC milled into these cubes. Ten cylinders (Ø 7.9mm, hight 17mm) and 20 disks (Ø 10mm, hight 3mm) were made of Y-TZP zirconia (ce.novation, Hermsdorf/Thuringia, D). The experimental veneering ceramic was layered between cylinders and disks in an even layer of 2mm and assembled into the cubes. Afterwards, the compound was fired.
In addition to the two kinds of experimental veneering, 1. IPS e.max Ceram (Ivoclar, Schaan, LI), 2. Heraceram Zirkonia (Heraeus Kulzer GmbH, Hanau, D) and 3. VM9 (VITA Zahnfabrik H. Rauter GmbH & Co. KG, Bad Säckingen, D) were tested in comparison. The tensile strength was tested in a universal testing machine (Z010, Zwick/Roell, Ulm, D).
Results were analyzed with one-way ANOVA (IBM SPSS 20.0).
Result:
Kind of veneering |
Number of samples |
Groups at level of significance alpha = 0.05. |
|
1 |
2 |
||
IPS e.max ceram |
10 |
224.60 |
|
Vita VM9 |
9 |
289.33 |
|
HeraCeram Zirkonia |
10 |
362.90 |
|
Experimental veneering 1 |
11 |
|
919.45 |
Experimental veneering 2 |
10 |
|
1024.20 |
Significance |
|
0.357 |
0.300 |
The table shows the mean force values at the time of fracture.
Conclusion:
Compared to the three commercially available veneering ceramic materials, both experimental materials showed significantly higher tensile bond strength. When checked against one another, the average force measured at fracture was about 300 N higher for the experimental veneering materials.
The bond between framework and veneering material was considerably improved.