RESUMO
Aim: This in vitro study evaluated the effect of using a dental hypersensitivity treatment on thebond strength to dentin of etch-and-rinse and self-etching simplified adhesive systems. Methods:40 healthy molars were used. The crowns of teeth were removed at the dentinoenamel junction,and remaining roots were sectioned in the mesiodistal direction along their long axis, separatingthe buccal and lingual/palatal halves. The segments obtained were ground, keeping the buccalor lingual/palatal face turned downwards in order to flatten the surface and produce a standardizedsmear layer. Prepared specimens were randomly distributed into 4 groups (n=10), according tothe combination of surface treatment with the desensitizing dentifrice Colgate Sensitive Pro-Relief(Colgate Palmolive®) (test group - with dentifrice and control group - without dentifrice) and typeof simplified bonding agent (etch-and-rinse and self-etching agents). Resin composite blockswere fabricated on the dentin surfaces, after application of bonding agents, and specimens weresectioned into rectangular stick-shaped specimens with cross-sectional area of approximately0.8mm2. For microtensile bond strength tests, 4 sticks were randomly selected from the centralregion of specimens, and fixed to a universal test machine. Data were analyzed statistically by theMann-Whitney U test (a=0.05). Results: The bond strength obtained in the group withoutdesensitizer (control) + etch-and-rinse agent was significantly higher compared with the othergroups. Under both experimental conditions, the self-etching agent showed weak bond strengthto dentin. Conclusions: Change in the dentin substrate by obliteration of tubules in the processof relieving dentinal sensitivity could reduce the bond strength of simplified etch-and-rinse andself-etching bonding agents.