Bond strength of different veneering ceramics to zirconia and their susceptibility to thermocycling.
OBJECTIVE
To evaluate the bond strength of recently developed feldspathic veneering ceramics to zirconium-oxide ceramic core material (Y-TZP). In addition, the effect of thermocycling on the bond strength was investigated.


METHODS
90 square Lava framework Y-TZP specimens were randomly assigned to three groups (n = 30) and veneered with one of the three zirconia veneering ceramics Cerabien ZR (CZR), GC Initial (GCI), or Lava Ceram (LC). 30 additional metal-ceramic specimens served as the control (VO). 15 specimens per group were stored in a saline solution for 3 days. To test the durability of the bond, 15 specimens per group were thermocycled for 10,000 cycles between 5 degrees to 60 degrees C with a 15-second dwell time. Shear strength was tested with an Instron universal testing system. A two-way ANOVA model and Tukey's HSD were applied for statistical analyses (alpha = 0.05).


RESULTS
The different material combinations revealed significantly different shear bond strength values (CZR > GCI > LC > VO). All veneering ceramic/zirconia combinations showed significantly higher bond strength than the metal-ceramic control VO. Bond strength values were not affected by thermocycling, except for CZR, which had significantly higher bond strength after thermocycling. Microscopic evaluation of failure modes revealed 100% cohesive failures in the veneering ceramic for all specimens.
Dept. of Preventive and Restorative Sciences, Robert Schattner Center, University of Pennsylvania, School of Dental Medicine, 240 S. 40th Street, Philadelphia, PA 19104, USA. mblatz@dental.upenn.edu
Markus B
MB
Blatz
Michael
M
Bergler
Fusun
F
Ozer
Stefan
S
Holst
Jin-Ho
JH
Phark
Gerard J
GJ
Chiche
D000538:Aluminum Silicates / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003801:Dental Veneers; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D016876:Metal Ceramic Alloys / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D033081:Shear Strength; D012965:Sodium Chloride / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
D000538:Aluminum Silicates; D003764:Dental Materials; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D017680:Potassium Compounds; C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; C016447:feldspar; D012965:Sodium Chloride; D015019:Yttrium; D015040:Zirconium; C028541:zirconium oxide