Dynamic versus static bond-strength testing of adhesive interfaces.
A static bond-strength test is often regarded as clinically less relevant, since such abrupt loading of the adhesive-tooth bond clinically never occurs. Therefore, dynamic fatigue testing is often claimed to better predict the clinical effectiveness of adhesives.


OBJECTIVE
To measure the micro-tensile fatigue resistance (μTFR) of adhesives bonded to dentin, and to compare their μTFR to their micro-tensile bond strength (μTBS).


METHODS
The bonding effectiveness (including fracture analysis) of three adhesives (OptiBond FL, Kerr: 3-step etch-and-rinse adhesive or 3-E&Ra; Clearfil SE, Kuraray: 2-step self-etch adhesive or 2-SEa; G-Bond, GC: 1-step self-etch adhesive or 1-SEa) was measured by means of both a dynamic μTFR and a static μTBS approach. Preparation and test set-up of the micro-specimens were identical for both tests. In fatigue, specimens were tested with a wide range of selected loads at 2Hz and at 10Hz until failure, or until 10(4) cycles were reached. At 2Hz, the μTFR was also measured after 3-month water storage. The μTFR was determined using a logistic regression model. Two-way ANOVA and Tukey HSD multiple comparisons test were used to determine statistical differences in μTBS.


RESULTS
The 1-SEa recorded significantly lower values in μTFR at 10Hz and in μTBS than the 2-SEa and 3-E&Ra. The 1-SEa and the 2-SEa performed significantly lower in μTFR than the 3-E&Ra, when tested at 2Hz after 3-month water storage. Fatigue testing at 2Hz after 1-week water storage did not reveal any differences in μTFR between the three adhesives.


CONCLUSIONS
The 3-E&Ra performed best in terms of bonding effectiveness, irrespective of the experimental condition or test used. The μTBS test proved once more to be a reliable laboratory test in ranking contemporary adhesives on their bonding effectiveness.
Poitevin
André
A
Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Belgium.
De Munck
Jan
J
Cardoso
Marcio Vivan
MV
Mine
Atsushi
A
Peumans
Marleen
M
Lambrechts
Paul
P
Van Meerbeek
Bart
B
D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry; 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; D014867:Water / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C498353:G-Bond; D008689:Methacrylates; C469607:OptiBond FL; D019279:Resin Cements; C083568:Z100 composite resin; D014867:Water; D012822:Silicon Dioxide; D015040:Zirconium