Microtensile bond strength to dentin of 4 self-etching adhesives after thermociclyng

Objectives: To evaluate the microtensile bond strength to dentin of self-etching adhesives after thermociclyng
Methods: 24 recently extracted caries and restoration free, human molars, were section with a slow speed saw to expose superficial dentin. Self-etching adhesives All Bond Universal (BISCO), Tetric N Bond SE (Vivadent), Single Bond Universal (3M ESPE), and total etch dentin bonding agent Single Bond 2 (3M ESPE) were place and light-cured over dentin following manufacturer’s instructions, 6 teeth per adhesive. Composite resin (Brilliant, Coltene) was placed over DBA in two incrments, light-curing each one for 40 seconds. Specimens were then sectioned to make sticks of 0.9 mm on each side, and 20 sticks were randomly selected among all samples collected from each adhesive and divided into two groups (n=10), one group was stored in water at 37 C for 30 days, and the other was thermocycled form 5 to 55 degrees with 30 seconds dwell time, for 5000 cycles. Specimens were tested in tensile at 0.1 cm/min until break on an universal testing machine (Tinius Olsen H10K-S). Bond strength was calculated in MPa, data were analyzed with two-way ANOVA calculated at 0.05 significance level. Means were compared using Tukey-Kramer interval also calculated at 0.05 significance level.
Results: Means (Std Dev) are shown in table. Highest µTBS was for Tetric N Bond thermocycled. Only Tetric N Bond SE when compared to Single Bond 2 had statistical difference. All others had statistically the same µTBS. All bond Universal was the only one with statistical same µTBS in both storage conditions. Others had statistically higher µTBS after thermocycling.
Conclusions: Thermocycling increased microTBS in three of the adhesives tested in this study.