Influence of surface pretreatment on the short-term bond strength of resin composite to a zirconia-based material.
OBJECTIVE
To evaluate the influence of airborne-particle abrasion of zirconia before and after sintering, on the bond strength between a zirconia core and an indirect resin composite material.


METHODS
9 disks of Y-TZP zirconia core were prepared and divided into three equal groups. In Group 1 pre-sintered Y-TZP zirconia was airborne-particle abraded with 120 microm alumina oxide. In Group 2 sintered Y-TZP zirconia was airborne-particle abraded with 120 microm alumina oxide. In Group 3 sintered Y-TZP zirconia was not treated and thus served as the control group. A 10-methacryloylooxydecyldihydrogenphosphate (MDP) containing bonding agent and silane coupling agent mixture was applied to the disks in all three experimental groups. Resin composite for indirect restorations was incrementally layered in a plastic mold to a final thickness of 3 mm. Specimens were sectioned under water cooling to obtain microsticks 6 x 1 x 1 mm in dimension. 30 microsticks per experimental group were generated. Microtensile bond strength test was conducted with a universal testing machine. Fractured microsticks and sections from each group were also examined under an optical microscope and a scanning electron microscope to evaluate respectively the mode of failure and the zirconia-composite interface. T-test for independent samples was selected to analyze the data. The level of significance was set at P < 0.05.


RESULTS
Airborne-particle abraded groups resulted in mean (SD) bond strength values of 25.65 (7.23) MPa for Group 1 and 24.65 (12.33) MPa for Group 2. Bond failures were mainly interfacial. In the control group a high number of premature failures occurred during cutting process and the mean (SD) bond strength recorded was 3.36 (4.17) MPa. It was concluded that airborne-particle abrasion of a zirconia substrate combined with application of a MDP-containing bonding/silane coupling agent mixture resulted in an adequate resin composite bond. Airborne-particle abrasion performed before sintering zirconia did not produce any significant differences.
Department of Dental Materials, University of Siena, Italy. fazi_90211@yahoo.com
Giovanni
G
Fazi
Alessandro
A
Vichi
Marco
M
Ferrari
D000537:Aluminum Oxide / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
D003188:Composite Resins; D003764:Dental Materials; C470230:Gradia; D008689:Methacrylates; D019279:Resin Cements; D012821:Silanes; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; C069749:methacryloyloxydecyl dihydrogen phosphate; D015040:Zirconium; D000537:Aluminum Oxide