Objectives: To test the working hypothesis that higher strain rates influence bond values in Microtensile testing. Methods: Twenty-four extracted non-carious human molars were selected, and the occlusal enamel of those teeth removed perpendicular to the tooth. The flattened teeth were randomly separated into groups for Single Bond (3M-ESPE Co) and Clearfil SE Bond (Kuraray Co) adhesive systems (12 teeth per system) with the bonding procedures performed following the manufacturer's directions. Subsequently, Z100 restorative composite resin (3M-ESPE Co.) of at least 4mm in total height was built up on top of each bonded substrate. Microtensile method was performed using the testing rates of 1mm/min (control), 12.7mm/min, 25.4mm/min, and 50mm/min for both adhesive systems (n=3). The bond strength data were analyzed by Two-Way ANOVA and Tukey test. Results: The table shows the MTBS mean (M), standard deviation (SD) and number of specimens (N) from each group (M+SD (N)). The statistical significance was defined a=0.5.
|
Groups |
1mm/min (Control) |
12.7mm/min |
25.4mm/min |
50.8mm/min |
|
Single Bond |
35.27±10.30 (31)xy |
40.27±15.16(51)yz |
33.34±15.15(86)x |
47.25±12.46(31)z |
|
P<0.05 |
no |
no |
no |
no |
|
Clearfil SE Bond |
38.05±13.59 (40)ab |
36.52±14.13(62)a |
31.81±9.59(69)a |
44.86±14.28(46)b |
Conclusion: The bond values were not significantly different for Single Bond and Clearfil SE Bond and were not strongly influenced by the strain rates employed. Supported by The Department of Biomaterials at New York University College of Dentistry and CNPq 201471/2003-5.