Fifty primary molars were grinded on the occlusal surface to obtain flat dentin substrate and randomly divided into 5 groups ( n = 10 ) : OFL : Phosphoric Acid/Optibond FL/Premise Flow ; OAO : Optibond All-In-One/Premise Flowable ; II : Polyacrylic Acid/Fuji II ; IX : Polyacrylic Acid/Fuji IX ; V : Vertise Flow .