Effect of Drying Technique on Bond Strength

Instructions for adhesive drying are commonly vague in nature. The purpose of this study was to determine the effect on bond strength of four different adhesive drying techniques on 3 dentin adhesives.

Methods:

120 human dentin specimens were mounted in acrylic cylinders with a 1 inch diameter. Three dentin bonding adhesives were used; Single Bond (S-3M), Excite (E-Vivadent), and OneStep (O-Bisco). The etchant gel used was Ultra-etch (Ultradent). Activation light was an Ultralume 5 (Ultradent). Resin composite was Z100 (3M).Dentin was treated with the Ultra-etch gel for 15 seconds and rinsed for five seconds with air-water spray. The excess water was blotted with a cotton roll. Three microbrushfuls of each adhesive were applied to the etched dentin. The adhesives were dried in the following manner: 1.air syringe 0.5 inches distance, 5 seconds duration, 90 degrees to bonded surface, full pressure, 2. syringe 2 inches distance, 5 seconds, 90 degrees, full, 3. syringe 0.5 inches distance, 45 degrees to surface, 5 seconds, full pressure, 4. syringe 2 inches, 5 seconds, 45 degrees, full. 40 lbs pressure was the pressure set in the syringe. The adhesives were then light-activated for 10 seconds. 10 teeth each group. Composite posts ( 2.38 mm diameter) were attached. Samples were tested immediately in a Universal testing machine with a crosshead speed of 1 mm.minute.

Results:

Mean (S.D.)

S1: 22.8(2.2) S2: 29.0(2.3) S3: 22.9(1.7) S4: 26.0(1.3)

E1: 10.5(3.2) E2: 25.5(1.2) E3: 11.7(2.6) E4: 25.0(2.1)

OS1: 18.0(0.6) OS2: 29.5(1.9) OS3:8.7(3.3) OS4:20.9(1.5)

Conclusions:

Drying Technique 2 yielded the highest bond strengths for each adhesive. Techniques 2 and 4 were significantly higher than 1 and 3. (p < .05) Drying technique can have a significant effect on adhesive bond strength. Well-defined, repeatable instructions are highly desirable in seeking consistent performance.