PURPOSE: To evaluate the effect of etching time on the nanoleakage and microtensile bond strength (microTBS) at the interface between etch-and-rise adhesives and dentin. METHODS: Eighty molars were sectioned to expose the superficial dentin and randomly divided into four groups according to the adhesives used: OptiBond Solo (OB), Single Bond (SB), One-Step (OS), and Prime&Bond NT (PB). Within each group, a total-etching technique was applied, and the dentin surfaces were etched for 0, 15, 30 or 60 seconds. Each treated tooth was then sectioned into sticks. A non-trimming microTBS test and TEM observation for nanoleakage were sequentially performed. RESULTS: The degree of nanoleakage increased as etching time increased (P < 0.05). For the OS and PB groups, the highest microTBS values were achieved with 15 seconds of etching, followed by 30, 60 and 0 seconds. For the OB and SB groups, the microTBS values for 15- and 30-second etching times were similar and were both significantly higher than those of 0 and 60 seconds (P < 0.05).
PURPOSE: To evaluate the effect of etching time on the nanoleakage and microtensile bond strength (microTBS) at the interface between etch-and-rise adhesives and dentin. METHODS: Eighty molars were sectioned to expose the superficial dentin and randomly divided into four groups according to the adhesives used: OptiBond Solo (OB), Single Bond (SB), One-Step (OS), and Prime&Bond NT (PB). Within each group, a total-etching technique was applied, and the dentin surfaces were etched for 0, 15, 30 or 60 seconds. Each treated tooth was then sectioned into sticks. A non-trimming microTBS test and TEM observation for nanoleakage were sequentially performed. RESULTS: The degree of nanoleakage increased as etching time increased (P < 0.05). For the OS and PB groups, the highest microTBS values were achieved with 15 seconds of etching, followed by 30, 60 and 0 seconds. For the OB and SB groups, the microTBS values for 15- and 30-second etching times were similar and were both significantly higher than those of 0 and 60 seconds (P < 0.05).