Effects of Ethanol-wet Dentin Bonding to Total-etch and All-in-One Adhesives

Objectives: The current study compared the effect of 50% and 90% ethanol to dentin bond strength with four different types of bonding agents. Immediate dentin shear bond strength (SBS) of three-step total-etch adhesive, Scotchbond Multi-purpose(SBMP), two-step total-etch, PeakLC(PLC), ethanol based all-in-one, Adper Easy Bond(EB) and acetone based all-in-one, iBOND(IB) were tested.

Methods: Caries-free extracted human molars were used to make occlusal dentin samples. Flat dentin surfaces were prepared using SiC paper to 320 grit. Filtek Supreme Ultra composite was used for all samples to make buttons using an Ultradent jig. SBMP: Dentin surface was etched, 50% or 90% ethanol was used to wet the surface, primed then a layer of adhesive was applied. PL: dentin surface was etched, re-wetted with ethanol followed by an adhesive layer. EB and IB: dentin surface was air-dried, wetted with ethanol then the adhesive was applied. Samples were stored in 37°C for 48 hours prior to occlusal shear bond testing using an Instron at a crosshead speed of 0.5mm/min.  

Results: Ethanol-wet bonding had no effect on hydrophobic SBMP (p >0.05) and acetone based hydrophilic IB (p >0.05). 50% ethanol wetting showed significantly higher SBS with ethanol based hydrophilic PLC (p=0.023) and EB (p=0.05). However, 90% ethanol wetting showed significantly lower SBS compared to 50% ethanol with PLC (p=0.0117) and EB (p=0.0209) and no difference with control groups (p >0.05). 

Mean Bond Strength (MPa ± SD)

	Control	50% EtOH	90% EtOH
SBMP	33.033 (±7.778)	29.415 (±8.199)	26.492 (±6.823)
PLC	19.838 (±2.589)	25.118 (±3.243)	17.460 (±4.762)
EB	25.547 (±3.382)	29.131 (±2.612)	23.984 (±3.823)
IB	11.752 (±2.195)	14.250 (±3.760)	13.415 (±2.457)

Conclusions: 50% ethanol wetting showed significantly higher SBS with ethanol based hydrophilic bonding agents, however, 90% ethanol wetting showed no benefits. Ethanol also did not show any effects with hydrophobic and acetone based hydrophilic adhesives.