Effect of simulated pulpal pressure on dentin bond strength of self-etching bonding systems.

ABSTRACT

PURPOSE: To evaluate in vitro the influence of dentin perfusion on dentin bond strengths of etch and rinse and self-etch adhesives. METHODS: 64 extracted human molars were ground flat and resin composite (Brilliant) was bonded using the following bonding systems (each n=16) OptiBond FL including phosphoric acid etching (OFL+), OptiBond FL without phosphoric acid etching (OFL-), Clearfil SE-Bond (CSE) and Prompt L-Pop (LP). In each bonding system, half of the specimens (n=8) were bonded without (PP-) and half with (PP+) simulated intrapulpal pressure. After water storage (37 degrees C, 24 hours), a 1 mm thick slice was cut vertically from the middle of each sample. Microtensile bond strength (microTBS) was determined and the debonded surfaces were investigated in SEM for the mode of failure. Statistical significance was determined by ANOVA, Tukey-test, and t-test (P= 0.05). RESULTS: Mean microTBS measured were (MPa +/- SD) OFL+/PP- 58.6 (5.8), OFL+/PP+ 38.1 (3.8), OFL-/PP- 37.9 (3.7), OFL-/PP+ 33.3 (3.5), CSE/PP- 41.1 (4.1), CSE/PP+ 39.0 (4.4), LP/PP- 35.8 (6.4), LP/PP+ 29.0 (4.8). The presence of PP resulted in a decrease of microTBS in all bonding systems, which reached significance in OFL+ (P< 0.0001), OFL- (P= 0.023) and LP (P= 0.032). Both, with and without PP, the bonding systems showed significant differences in bond strength (ANOVA P< 0.0001).