Objective: To evaluate the effect of pre-treatment with different collagen cross-linkers in a clinically relevant time period on the immediate and delayed bond strength of two different etch and rinse adhesives to dentin.

Materials and methods: Flat coronal dentin surfaces were prepared in 132 extracted human molars. Teeth were randomly divided into six groups according to three different surface pre-treatments: (i)no pretreatment (ii)3% riboflavin pretreatment (iii) 2M EDC pretreatment and two adhesive systems (Prime & Bond NT and Optibond Solo Plus) used. Composite cylinder build ups were done in all the samples. Ten

samples from each group were subjected to immediate shear bond strength (SBS) evaluation and ten samples were stored for delayed (nine months) SBS evaluation. Additionally, two samples per group were subjected to scanning electron microscopic analysis for observation of resin-dentin interface.

Results: Treatment of acid etched dentin with 2M EDC or 3% riboflavin for one minutebefore adhesive application resulted in significantly higher SBS values of both the etch and rinse adhesives when compared to the control groups after nine months storage.

Conclusion: Dentin pretreatment with both the collagen cross-linkers resulted in significantly higher resin-dentin bond strength at nine months for both the adhesives tested.