Effects of solvent drying time on micro-shear bond strength and mechanical properties of two self-etching adhesive systems.
OBJECTIVE
The all-in-one adhesives are simplified forms of two-step self-etching adhesive systems that must be air dried to remove solvent and water before curing. It was investigated whether those two systems perform equally well and if their performance is affected by air-drying of the solvent containing agent.


METHODS
Two adhesive systems (both by Kuraray Medical) were evaluated; Clearfil Tri-S bond (TS) and Clearfil SE bond (SE). Micro-shear bond strengths to human dentin after solvent air-drying times of 2, 5 or 10 s for each group were measured (n=10). The indentation creep and hardness of the bonding layer were also determined for each group.


RESULTS
The lowest micro-shear bond strength, nano-indentation hardness and creep stress exponents were obtained for 2 s air dried specimens of each material. After 10 s air blowing, SE showed superior properties compared to TS groups (p<0.05).


CONCLUSIONS
When properly handled, two step self-etching material performs better than the all-in-one adhesive. Air-drying is a crucial step in the application of solvent containing adhesives and may affect the overall clinical performance of them, through changes in the bond strength and altering nano-scale mechanical properties.
Sadr
Alireza
A
Cariology and Operative Dentistry, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. alireza.ope@tmd.ac.jp
Shimada
Yasushi
Y
Tagami
Junji
J
D000134:Acid Etching, Dental / Q000379:methods*; D000388:Air; D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation; D004548:Elasticity; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012997:Solvents / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014783:Viscosity
C438313:Clearfil SE Bond; C515604:Clearfil Tri-S Bond; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D012997:Solvents