Influence of surface treatments and resin cement selection on bonding to densely-sintered zirconium-oxide ceramic.
OBJECTIVE
To evaluate the effect of surface conditioning on the microtensile bond strength of zirconium-oxide ceramic to dual-cured resin cements.


METHODS
Eighteen cylinder-shaped zirconium-oxide ceramic blocks (Cercon Zirconia, Dentsply) were treated as follows: (1) Sandblasting with 125 microm aluminum-oxide (Al(2)O(3)) particles; (2) tribochemical silica coating using 50 microm Al(2)O(3) particles modified by silica; (3) no treatment. Each ceramic cylinder was duplicated in composite resin (Tetric Evo Ceram, Ivoclar-Vivadent) using a silicon mold. Composite cylinders were bonded to conditioned ceramics using: (1) Calibra (Densply Caulk); (2) Clearfil Esthetic Cement (Kuraray); (3) Rely x Unicem (3M ESPE). After 24h bonded specimens were cut into microtensile sticks that were loaded in tension until failure. Data were analyzed using two-way ANOVA and Student-Newman-Keuls test for multiple comparisons (p<0.05). Failure mode was recorded and the interfacial morphology of debonded specimens was observed using a scanning electron microscope (SEM). Surface topography and ceramic average surface roughness were analyzed under an atomic force microscope (AFM).


RESULTS
Significant changes in zirconia surface roughness occurred after sandblasting (p<0.001). Bond strength of Clearfil cement to zirconia was significantly higher than that of Rely x Unicem and Calibra, regardless of the surface treatment (p<0.001). When using Calibra, premature failures occurred in non-treated and silica coated zirconia surfaces.


CONCLUSIONS
The phosphate monomer-containing luting system (Clearfil Esthetic Cement) is recommended to bond zirconia ceramics and surface treatments are not necessary.
de Oyagüe
Raquel Castillo
RC
Department of Prosthodontics, Faculty of Dentistry, University Complutense of Madrid, Madrid, Spain.
Monticelli
Francesca
F
Toledano
Manuel
M
Osorio
Estrella
E
Ferrari
Marco
M
Osorio
Raquel
R
D000537:Aluminum Oxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D045662:Dental Etching; D003776:Dental Porcelain / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry*
C433205:Calibra; D003188:Composite Resins; C483701:Rely X Unicem; D019279:Resin Cements; C501891:Tetric EvoCeram; C530542:clearfil esthetic cement; D003776:Dental Porcelain; D012822:Silicon Dioxide; D015040:Zirconium; D000537:Aluminum Oxide; C028541:zirconium oxide