Method: Five adhesive groups: Bond Force (BF, self-etch 1step (SE1) with SR, Tokuyama), Bond Force no-SR (NSR, experimental SE1, Tokuyama), Optibond FL (OBFL, total-etch 3step Kerr), Clearfil SE (CSE, self-etch 2step, Kuraray) and Optibond All-in-One (OBA, SE1, Kerr) were tested. 150 Extracted human molars were randomly distributed into five adhesive groups. Dentine surfaces were prepared using CNC Specimen Former (University of Iowa). The adhesives were applied according to manufacturer's instructions. Resin-based composite (Z100, 3M-ESPE) ‘crowns’, approximately 5mm in height, were incrementally formed and light-cured. Each restored tooth was sectioned into 2x2mm square sticks with diamond blades then into dumbbell-shaped specimens with the CNC (0.5mm2 round cross-sectional area, 1mm gage-length, 0.6mm radius of curvature). The specimens were stored for two-years in artificial saliva containing sodium azide (changed monthly) at 37ºC. Specimens were tensile-tested at a crosshead speed of 1mm/min in a calibrated testing machine (Z2.5, Zwick). The data was analyzed by two-way ANOVA with post-hoc Turkey's test (alpha=0.05). Additional specimens per each group were subjected to a silver impregnation protocol and nanoleakage patterns were observed under TEM.
Result: The mTBS means and standard deviations are presented in the table below. Pre-test failures were included as 1MPa. Means followed by same letters (number for rows, character for columns) are not significantly different.
Material (n=30) |
24hr |
24mo |
Bond Force |
58.2(10.5) A,1 |
31.8(7.6) B,2 |
Bond Force no SR |
38.3(17.5) B,1 |
18.8(11.6) C,2 |
Optibond FL |
56.4(8.8) A,1 |
43.2(11.3) A,2 |
Clearfil SE |
55.9(12.7) A,1 |
44.7(13.8) A,2 |
Optibond All-in-one |
55.0(11.8) A,1 |
33.7(12.8) B,2 |
Conclusion: The bonding effectiveness of SR technology applied to a one bottled adhesive system for dentin bonding was confirmed.
Mr. Yamagawa was employed by Tokuyama Dental Corp. while a visiting scientist at the University of Iowa.