Fatigue resistance of the bond of a glass-infiltrated alumina ceramic to human dentin.
OBJECTIVE
To evaluate the fatigue resistance of the bond between dentin and glass-infiltrated alumina ceramic, using different luting protocols.


METHODS
The null hypothesis is that the fatigue resistance varies with the luting strategy. Forty blocks of In-Ceram Alumina were prepared, and one surface of each block was abraded with 110-microm aluminum oxide particles. Then, the blocks were luted to flat dentin surfaces of 40 human third molars, using 4 different luting strategies (luting system [LS]/ceramic surface conditioning [CSC]) (n=10): (G1) [LS] RelyX-Unicem/[CSC] airborne abrasion with 110-microm Al2O3 particles; (G2) [LS] One-Step + Duo-Link (bis-GMA-based resin)/[CSC] etching with 4% hydrofluoric acid + silane agent; (G3) [LS] ED-Primer + Panavia F (MDP-based resin)/[CSC] Al2O3; (G4) [LS] Scotchbond1+RelyX-ARC (bis-GMA-based resin)/[CSC] chairside tribochemical silica coating (air abrasion with 30-microm SiOx particles + silane). After 24 h of water storage at 37 degrees C, the specimens were subjected to 106 fatigue cycles in shear with a sinusoidal load (0 to 21 N, 8 Hz frequency, 37 degrees C water). A fatigue survivor score was given, considering the number of the fatigue cycles until fracture. The failure modes of failed specimens were observed in a SEM.


RESULTS
G3 (score = 5.9, 1 failure) and G4 (score = 6, no failures) were statistically similar (p = 0.33) and had significantly higher fatigue resistance than G1 (score = 3.9, 5 failures) and G2 (score = 3.7, 6 failures) (p < 0.03). SEM analysis of fractured specimens of G1 and G2 showed that almost all the failures were between ceramic and cement.


CONCLUSIONS
The MDP-based resin cement + sandblasting with Al2O3 particles (G3) and bis-GMA-based resin cement + tribochemical silica coating (G4), both using the respective dentin bonding systems, were the best luting protocols for the alumina ceramic. The null hypothesis was confirmed.
Baldissara
Paolo
P
Department of Oral Science, University of Bologna, Italy.
Valandro
Luiz Felipe
LF
Monaco
Carlo
C
Ferrari
Marco
M
Bottino
Marco Antonio
MA
Scotti
Roberto
R
D000134:Acid Etching, Dental; D020906:Air Abrasion, Dental; D000537:Aluminum Oxide / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D003738:Dental Cements; D017220:Dentin-Bonding Agents; C431350:Duo-Link; C500742:ED Primer II; D008689:Methacrylates; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; D012821:Silanes; D003776:Dental Porcelain; C070870:In-Ceram; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; C041330:Scotchbond; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid