evidence: There were no significant differences in SBS values among groups one, two and three (10.7 ± 2.24, 10.09 ± 2.39 and 8.94 ± 2.17 MPa, respectively) (P>0.05), but group four (6.12 ± 2.04 MPa) showed significantly lower value compared to others (P < 0.05)
intervention: pH 3.8 saliva 
comparator: pH 6.8 saliva
outcome: Shear bond strength