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Objective: The purpose of this study was to investigate the immediate and three-month water storage behavior of adhesives when used for immediate dentin sealing (IDS)., Methods and Materials: Four adhesive systems were used to perform IDS: a one-step self-etch (Xeno V), a two-step self-etch (Clearfil SE Bond), a two-step etch-and-rinse (XP Bond), and a three-step etch-and-rinse (Optibond FL). For the control group, IDS was not performed. The self-adhesive resin cement RelyX Unicem was used for the luting procedures. After seven days of water storage, specimens (n=6) were sectioned into beams (n=5) with an approximately 1-mm 2 cross-sectional area. Half of the specimens were tested in tension after seven days of water storage at 37°C, while the other half was stored for three months prior to testing in tension using a universal testing machine (1 mm/min). The failure pattern was determined using a stereomicroscope and scanning electron microscopy. Microtensile bond strength (μTBS) data were statistically analyzed by two-way analysis of variance and Tukey post hoc test (α=0.05)., Results: After seven days, the control group presented the lowest μTBS but did not differ from XP Bond and Clearfil SE Bond. After three months, there was no μTBS difference between the IDS groups and the control., Conclusions: After seven days of water storage, the groups with IDS presented higher μTBS values than the control group, although XP Bond and Clearfil SE Bond did not present significant differences. However, after three months of storage in water, IDS groups did not differ significantly from control group, which did not receive IDS.

Objectives: This study evaluated the effect of the application mode on the microtensile resin-dentin bond strength (microTBS) and silver nitrate uptake (SNU) of three one-step self-etch adhesives systems (Clearfil S3 Bond [S3], Xeno III [XE] and Adper Prompt L-Pop [AD])., Materials and Methods: The occlusal enamel of 30 caries-free extracted molars was removed with a slow-speed diamond saw under copious water-cooling in order to expose a flat dentin surface. The adhesives were applied passively or with agitation. After light-curing (600 mW/cm2 for 10 seconds), composite buildups were constructed incrementally and the specimens were stored in water (37 degrees C/24 hours). The specimens were longitudinally sectioned in the "x" and "'y" direction to obtain bonded sticks (0.8 mm2) to be tested immediately in tension at 0.5 mm/minute. For SNU, two bonded sticks from each tooth were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. The microTBS and SNU data were submitted to two-way ANOVA and Tukey's test (alpha=0.05)., Results: Regarding the microTBS, only the main factor mode of application was statistically significant (p = 0.01). All adhesives showed higher microTBS when applied with agitation. Regarding SNU, only the main factor adhesive was statistically significant (p = 0.001). A higher amount of silver nitrate uptake, located in both the hybrid and adhesive layer, occurred for AD, regardless of the mode of application., Conclusions: Application with agitation on the dentin surface is a clinical tool capable of improving the resin-dentin bond strength of one-step self-etch adhesives; however, this clinical approach does not improve the hybrid layer resistance to silver nitrate uptake.

The current study evaluated the effect of 2% chlorhexidine digluconate (CHX) on the immediate and six-month resin-dentin bond strength (BS) and nanoleakage pattern (NL) of etch-and-rinse adhesives when applied in aqueous or associated to the phosphoric acid conditioner. The occlusal enamel of 42 caries-free extracted molars was removed in order to expose a flat dentin surface. In groups 1 and 2 (control-C), the surfaces were acid etched with conventional phosphoric acid, and the adhesives Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied after rinsing, drying and rewetting with water. In groups 3 and 4 (Ac/CHX), the adhesives were applied in a similar manner, however, a 2% CHX-containing acid was previously applied. In groups 5 and 6 (CHX), the adhesives were applied according to the control group; however, the rewetting procedure was performed with an aqueous solution of 2% CHX for 60 seconds. Composite buildups (Opallis, FGM) were constructed incrementally, and the specimens were longitudinally sectioned in the "x" and "y" directions to obtain bonded sticks (0.8 mm2) to be tested in tension at 0.5 mm/minute immediately or after six months of water storage. For NL, two bonded sticks from each tooth were coated with nail varnish, placed in silver nitrate and polished down with SiC paper. Resin-dentin interfaces were analyzed by EDX-SEM. The BS and NL data from each adhesive was submitted to two-way repeated measures ANOVA and Tukey's test (alpha=0.05). After six months of water storage, significant reductions in BS were observed for both adhesives in the control group (p<0.05). When Ac/CHX or CHX was used, no significant reductions in BS were observed for both systems. Nanoleakage was more evident in the control group than in the experimental groups (p<0.05), even after six months. The use of CHX in an aqueous solution or associated with the acid conditioner was effective for reducing degradation of resin-dentin bonds after six months of water storage.