Objective: The aim of this study was to evaluate the effect of two surface contaminants and different cleansing agents on the resin bond strength of partially stabilized zirconia.

Method: 80 partially stabilized zirconia samples were randomly divided into two groups (n=40) according to the surface contaminant into Group (S): saliva, Group (D): disclosing agent. Each group was subdivided into three subgroups (n=10) according to the cleansing method into group (V): Ivoclean agent, group (A): air abrasion, group (W): water, and then Groups (SC) and (DC): (surface contamination and no cleaning) (n=20). Bonding was done by applying resin cement to the treated surfaces in all groups. After that, all prepared specimens were thermocycler 5000 cycles, followed by an SBS test and then an assessment of the mode of failure.

Results: Images showed that adhesive failure in the resin interface was more predominant in contaminated groups with no surface cleaning and in groups where water was used as a cleaning agent, while mixed failures were found in groups that used Ivoclean, and Airborne particle abrasion, was more predominant in the latter.

Conclusion: Contaminants adversely affected the shear bond strength of resin cement to the zirconia surface. Airborne particle abrasion appears to be the most effective among the different cleansing methods (SBS 32.25 MPa), followed by Ivoclean (SBS 18.28 MPa), exceeding the minimally acceptable range of SBS for clinical use (15 to 21 MPa). However, SBS was lower in the contaminated non-cleansed or water-cleansed groups, suggesting that cleansing is necessary.