Influence of oil contamination on in vitro bond strength of bonding agents to dental substrates.
OBJECTIVE
To evaluate the influence of cleaning procedures (pumice, anionic detergent and both procedures together) on the tensile bond strength of etch-and-rinse and self-etch adhesive systems to bovine enamel and dentin in vitro.


METHODS
Eighty non-carious, bovine incisors were extracted, embedded in acrylic resin to obtain enamel/dentin specimens. Flat bonding surfaces were obtained by grinding. Groups were divided according to substrate (enamel or dentin), adhesive system [etch-and-rinse, Adper Single Bond 2 (SB) or self-etch, Clearfil Protect Bond (PB)]; and cleaning substances (pumice, anionic detergent and their combination). The teeth were randomly divided into 20 groups (n=8): G1--Enamel (E) + SB; G2--E + oil (O) + SB; G3--E + O + Pumice (P) + SB; G4--E + O + Tergentol (T) + SB; G5--E + O + P + T + SB; G6--E + PB; G7--E + O + PB; G8--E + O + P + PB; G9--E + O + T + PB; G10--E + O + P + T + PB; G11--Dentin (D) + SB; G12 D + SB + O; G13--D + SB + O + P; G14--D + SB + O + T;G15--D + SB + O + P + T; G16--D + PB; G17--D + O + PB +; G18--D + O + P + PB; G19--D + O + T + PB; G20--D + O + P + T + PB. Specimens were contaminated with handpiece oil for 5 seconds before bonding. Adhesive systems and resin composite were applied according to manufacturers' instructions. Specimens were tested in tension after 24 hours of immersion using a universal testing machine at a crosshead speed of 0.5 mm/minute. Bond strengths were analyzed with ANOVA. Failure sites were observed and recorded.


RESULTS
Tensile bond strength in MPa were: G1 (23.6 +/- 0.9); G2 (17.3 +/- 2.2); G3 (20.9 +/- 0.9); G4 (20.6 +/- 0.5); G5 (18.7 +/- 2.3); G6 (23.0 +/- 1.0); G7 (21.5 +/- 2.4); G8 (19.9 +/- 1.3); G9 (22.1 +/- 1.2); G10 (19.1 +/- 1.2); G11 (18.8 +/- 1.3); G12 (15.7 +/- 2.1); G13 (17.8 +/- 3.3); G14 (15.3 +/- 2.9); G15 (15.6 +/- 1.9); G16 (14.7 +/- 2.3); G17 (5.5 +/- 0.9); G18 (19.3 +/- 1.8); G19 (15.6 +/- 1.6); G20 (20.3 +/- 3.9). Statistical analysis showed that the main factors substrate and cleaning were statistically significant, as well as the triple interaction between factors of variance. However, the factor adhesive system did not show statistical difference. Oil contamination reduced bond strengths, being less detrimental to enamel than to dentin. Etch-and-rinse (SB) and two-step self-etch (PB) systems had similar bond strengths in the presence of oil contamination. For etch-and-rinse (SB), the cleaning procedures were able to clean enamel, but dentin was better cleaned by pumice. When self-etch (PB) system was used on enamel, anionic detergent was the best cleaning substance, while on dentin the tested procedures were similarly efficient.
Matos
Adriana Bona
AB
Department of Restoratve Dentistry, Faculty of Dentistry of the University of São Paulo, São Paulo, SP, Brazil. bona@usp.br
Oliveira
Denise Cerqueira
DC
Vieira
Samuel Nilo
SN
Netto
Narciso Garone
NG
Powers
John M
JM
D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003902:Detergents / Q000737:chemistry; D007219:Industrial Oils; D008422:Materials Testing; D011897:Random Allocation; D017640:Silicates / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
C503075:Clearfil Protect Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D003902:Detergents; C444701:Filtek Z250; D017640:Silicates; C115612:single bond; D014867:Water; D017438:Bisphenol A-Glycidyl Methacrylate; C005144:pumice