Microtensile strength of composite bonded to hot-pressed ceramics.
OBJECTIVE
The objective of this in vitro study employing the microtensile test was to test the hypothesis that the tensile bond strength of hot-pressed ceramics to composite is controlled by the ceramic microstructure and the ceramic surface treatment.


METHODS
Hot-pressed IPS Empress (E1) and IPS Empress 2 (E2) ceramic blocks were polished with 1-micron alumina abrasive and treated as follows: group 1: 9.6% hydrofluoric acid (HF) on E1; group 2: 4% acidulated phosphate fluoride (APF) on E1; group 3: silane (S) on E1; group 4: HF + S on E1; group 5: APF + S on E1; group 6: HF on E2; group 7: APF on E2; group 8: S on E2; group 9: HF + S on E2; group 10: APF + S on E2. The surfaces as described above were then treated with Scotchbond Multi-Purpose Plus and covered with composite (Z-100). From the blocks obtained in this manner, specimens for microtensile testing were created by sectioning. Twenty bar specimens for each group were loaded to failure under tension using an Instron testing machine.


RESULTS
Mean tensile bond strength (MPa) and standard deviation values are as follows: (1) 9.9 +/- 1.2; (2) 0; (3) 27.2 +/- 4.8; (4) 20.6 +/- 3.0; (5) 13.6 +/- 4.5; (6) 41.7 +/- 6.7; (7) 19.1 +/- 2.6; (8) 30.1 +/- 5.3; (9) 56.1 +/- 4.1; (10) 36.9 +/- 3.9. All fractures occurred within the adhesion zone. SEM images of chemically etched specimens revealed that HF produced greater surface degradation and greater bond strength than APF for both E1 and E2 ceramics. The mean bond strength of groups 6 through 10 (E2) was significantly greater than that of groups 1 through 5 (E1) for each treatment condition.


CONCLUSIONS
The tensile fracture resistance of the composite-ceramic adhesion zones is controlled primarily by ceramic microstructure and ceramic surface treatment.
Della Bona
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A
Department of Dental Biomaterials, University of Florida, PO Box: 100446, Gainesville, FL 32610-0446, USA. adellabona@dental.ufl.edu
Anusavice
K J
KJ
Shen
C
C
D000134:Acid Etching, Dental; D000149:Acidulated Phosphate Fluoride / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry*; D002516:Ceramics / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide; D013499:Surface Properties; D013718:Tensile Strength; D015040:Zirconium
D000538:Aluminum Silicates; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C075815:IPS-Empress ceramic; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; D012821:Silanes; C083568:Z100 composite resin; D003776:Dental Porcelain; D000149:Acidulated Phosphate Fluoride; D012822:Silicon Dioxide; D015040:Zirconium; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid